Physics Challenge英国物理挑战杯-2013-QuestionPaper问卷
译事三难信达雅
国际青年物理锦标赛（IYPT）历届竞赛题（1988-2016）译事三难信达雅翻译，从来都是一件困难的事情。
比如说，International Young Physicists'Tournament(IYPT)似乎应当翻译为“国际青年物理学家锦标赛”，可是，在中国，物理学家是个很大的词儿，甚至物理学工作者这个谦虚得多的词儿，都不太适合，因为这个竞赛面对的是中学生，而physicist不过就是个“做物理的人”，甚至只是个“做物理题的人”。
所以呢，把它称为“国际青年物理锦标赛”，也许更符合中国国情。
当年把IYPT移植到国内的那些人，想必也考虑过这个问题。
IYPT 在中国的对应物是中国大学生物理学术竞赛（CUPT）和中国高中生物理创新竞赛（CYPT）：T还是同样的T，同样的Tournament，但已经不强调“锦标主义”了；P还是同样的P，但是英文里的Phyisicist 已经变为Physics了。
或许基于类似的考虑，虽然CUPT和CYPT采用的都是IYPT的问题，但是从来都没有正式的中文译本。
参加竞赛的人，当然能读懂英文试题，但是，我确实看到有些人读错了题意，还有更多的人在学术问答阶段争辩具体问题里的微言大义，我觉得这都是白白浪费了时间。
IYPT的问题不同于普通的习题。
普通的习题，你总可以在五分钟里找到思路；IYPT的问题，也许需要你几天乃至更长的时间。
另外，在我看来，IYPT的题目，只是给你个出发点而已，让你大致了解所谓的科研是怎么回事。
真的把它当成习题来做，就浪费了。
解决这些问题，也不需要从文献入手。
IYPT的作用，更主要的是吸引更多的学生对物理感兴趣，让他们了解从哪里下手解决问题。
很多低年级的大学生面临的问题是，他们其实并不一定相信自己学到的知识：答题的时候，尽可以头头是道；真正要自己分析问题的时候，就懵了。
中学生就更不用说了。
还有一个很严重的问题是：现在其实没有什么真正的问题，要么太难，要么太没有意思。
学生会干部职务竞赛奖项等英文表达
精品文档一、学生会干部职务（中英文）分管秘书处、()、内务副主席主席团[主席、外务副主席(分管宣传部、公关部、文体部 1.)]校风部、社团部Presidium: Chairman, Vice President(External)(In charge of Publicity Department, PublicRelations Department, Recreation and Sports Department ), Vice President(Internal) (in charge ofSecretariat, School Spirit Department, Clubs Department))]分管文书、人事、副秘书长(秘书长、副秘书长(分管财政、庶务) 2. 秘书处[Secretariat [Secretary General, Assistant Secretary General (in charge of Finance and businessmatters), Assistant Secretary General (in charge of writ and personnel)]兼学、副部长(、副部长(兼广播站站长)3. 宣传部[部长、副部长(分管海报、黑板报工作))](兼学生会报刊社长生会网网主)、副部长Publicity Department[Minister, Assistant Minister(in charge of Poster and Blackboardnewspaper),Assistant Minister(also Radio Station Master ),Assistant Minister(also Executive ofInternet for Student Union), Assistant Minister(also Proprietor of Newspaper of Student Union)]勤工俭、副部长(分管学生生活、住宿、[4. 校风部部长、副部长(分管学生纪律、权益)Minister, Assistant Minister (in charge of ：(分管学术交流)] School Spirit Department学)、副部长efits), Assistant Minister (in charge of students' daily life, lodging, discipline, rights and benpart-work and part-study system), Assistant Minister (in charge of ))] Public (兼礼仪队队长、副部长、副部长(分管外联)部长、副部长5. 公关部[(分管内联) ：Minister, Assistant Minister (in charge of academic exchange) Relations Department分管实()(分管文体、学术类社团工作、副部长6. 社团部(又称社团联合会)[部长、副部长]践、理论类社团工作Minister, Assistant Minister (in charge of recreations and ：Clubs Association DepartmentSports activities, responsible for the liaison of clubs for academic exchange,), Assistant Minister(responsible for the liaison of clubs for theories and practices ))](分管体育类工作(分管文艺工作)、副部长文体部7. [部长、副部长Recreation and Sports Department: Minister, Assistant Minister (in charge of literature and art), Assistant Minister (in charge of sports)外加：8.外联部:Diplomacy Department: Recreation Department 娱乐部: Executive Vice President 执行副主席二、班干部（中英文）班长monitor精品文档．精品文档副班长vice-monitorCommissary in charge of studies 学习委员Commissary in charge of entertainment 文娱委员体育委员Commissary in charge of sports劳动委员Commissary in charge of physical laborParty branch secretary 党支部书记League branch secretary 团支部书记Commissary in charge of organization组织委员宣传委员Commissary in charge of publicityCommissary in charge of subsistence 生活委员心理委员Commissary in charge of psychological三、竞赛（中英文）“Challenge Cup”Undergraduate Curricular Academic 大学生课外学术科技作品竞赛“挑战杯”Science and Technology Works Contest Mathematical Undergraduate Cup”Contemporary 高教社杯全国大学生数学建模竞赛“HEPContest in ModelingThe Mathematical Contest in Modeling (MCM)美国数学建模比赛Plus”College Students' “Internet 大学生创新创业大赛The 1st China 首届中国互联网+Innovation and Entrepreneurship CompetitionNational Undergraduate Electronic Design Contest全国大学生电子设计竞赛st China Collegiate Computing 2018 the 1首届中国高校计算机大赛—人工智能创意赛2018Contest - Artificial Intelligence Innovation Contest“FLTRP Cup”National English Writing Contest “外研社杯”全国英语写作大赛“FLTRP Cup”English Public Speaking Contest 全国英语演讲大赛外研社杯”“National English Competition for College Students (Band C) C类）全国大学生英语竞赛（stst Daily 21“21 China The 全国英语演讲比赛世纪第二十一届中国日报社“21?可口可乐杯”-Cola Cup”National English Speaking CompetitionCentury?Coca th All China Interpreting Contest (Henan Division) （河南赛区）The 7第七届全国英语口译大赛in Competition College China Students' Entrepreneurship 全国大学生创业大赛创青春2016“”2016National 3D Innovation Design Competition全国三维数字化创新设计大赛精品文档．精品文档JD Finance Campus Marketing Competition 京东金融校园营销挑战赛5th The +西”大学生国际海报双年展（中国／武汉）入围奖Candidate Award of 第五届“东“East + West”College Students' International Poster Biennale Works Collection (China·Wuhan)Digital 上海大学生文化创意作品展The 2nd Think Youth Shanghai 第二届“汇创青春”——Creation, Innovation, and Entrepreneurship Contest2018 Chinese Trademark Creative Design Contest 2018中华商标创意设计大赛Shanghai International College Students Advertising Festival上海国际大学生广告节Arts Dance Performing Cup”Music and Academy “学院杯”黑龙江省中学生艺术节“Competition in Heilongjiang Province四、资格证书（中英文）Business English Certificate Vantage 中级BECCertificate of Accounting Profession 会计从业资格证书Financial Planning Certificate 理财规划师证The Securities Qualification Certificate证券从业资格证National Computer Rank Examination Certificate (Grade 1)全国高等学校计算机一级证书Teacher Certification 教师资格证Senior Purchasing Manager高级采购经理National Psychological Counselor Certificate (Level 3) 国家三级心理咨询师证书Human Resource Professional (Level-3) 国家三级企业人力资源管理师Enterprise Training Specialist 国家企业培训师证National Assistant Social Worker国家助理社会工作师ocational Qualification Certificate Dietitian V 营养师职业人员资格证书五、奖学金、奖励和荣誉称号（中英文）National Encouragement Scholarship 国家励志奖学金Individual Scholarship 单项奖学金人民奖学金People's Scholarship精品文档．精品文档Special Grade Scholarship 特等奖学金Comprehensive Scholarship 综合奖学金一等奖学金First-class ScholarshipAcademic Progress Award 学习进步奖The First/Second/Third Prize//一二/三等奖Excellent Student for Academic Performance 学习特优生Merit Student 三好学生Excellent Student Cadre优秀学生干部Excellent Cadre of Communist Youth League (CYL) of China 优秀团干部Outstanding Graduate 优秀毕业生Group Champion 团体冠军精品文档．。
第35届国际物理奥林匹克竞赛实验试题及解答(英文)
Mechanical “Black Box” and rotation stage
Rotating stub
Weight with a string
京翰教育中心/
高中物理辅导网/
Mechanical “Black Box”
1. 2. 3. 4. 5. 6. The time available is 5 hours. Use only the pen provided. Use only the front side of the writing sheets. Write only inside the boxed area. In addition to the blank writing sheets, there are Answer Forms where you must summarize the results you have obtained. Write on the blank writing sheets the results of your measurements and whatever else you consider is required for the solution to the question. Please, use as little text as possible; express yourself primarily in equations, numbers, fixes at the top of each sheet of paper write down your country code (Country Code) and student number (Student Code). In addition, on each blank writing sheets, write down the progressive number of each sheet (Page Number) and the total number of writing sheets used (Total Number of Pages). If you use some blank writing sheets for notes that you do not wish to be marked, put a large X across the entire sheet and do not include it in your numbering. At the end of the experiment, arrange all sheets in the following order: • Answer forms (top) • used writing sheets in order • the sheets you do not wish to be marked • unused writing sheets • the printed question (bottom) It is not necessary to specify the error range of your values. However, their deviations from the actual values will determine your mark. Place the papers inside the envelope and leave everything on your desk. You are not allowed to take any sheet of paper or any material used in the experiment out of the room.
2013英国奥林匹亚化学竞赛
45th INTERNATIONALCHEMISTRY OLYMPIAD2013UK Round OneSTUDENT QUESTION BOOKLET* * * * *■The time allowed is 2 hours.■Attempt all 5 questions.■Write your answers in the special answer booklet.■In your calculations, please write only the essential steps in the answer booklet.■Always give the appropriate units and number of significant figures.■You are provided with a copy of the Periodic Table.■Do NOT write anything in the right hand margin of the answer booklet.■The marks available for each question are shown below; this may be helpful when dividing your time between questions.Question 1 2 3 4 5 TotalMarksAvailable9 13 9 15 17 63Some of the questions will contain material you will not be familiar with. However, by logically applying the skills you have learnt as a chemist, you should be able to work through the problems. There are different ways to approach the tasks – even if you cannot complete certain parts of a question, you may still find subsequent parts straightforward.H180 0 . 1 eH 230 0 . 4 i L 3 4 9 . 6 e B 4 10 . 9 lo b m y s r e b m u n c i m o t a r e l a t i v e a t o m i c m a s sB 5 1 8 . 0 1C 6 1 0 . 2 1 N 7 1 0 . 4 1 O 8 00 . 6 1 F90 . 9 1 eN 01 81 . 02 a N 1 1 9 9 . 2 2 g M 2 1 13 .4 2 l A 31 89 . 6 2 iS 41 9 0 . 82 P 5 1 79 . 0 3 S6 1 60 . 2 3 lC 7 1 54 .5 3 rA 8 1 59 . 9 3 K 9 1 2 0 1 . 9 3 a C 0 2 8 0 . 0 4 c S 1 2 6 9 . 4 4 i T 2 2 0 9 . 7 4 V 3 2 49 . 0 5 rC 42 0 0 . 2 5 n M 5 2 4 9 . 4 5 e F 6 2 5 8 . 5 5 oC 7 2 3 9 . 8 5 i N 8 2 1 7 . 8 5 u C 9 2 5 5 . 3 6 n Z 0 3 7 3 . 5 6 a G 1 3 2 7 . 9 6 e G 2 3 95 . 2 7 sA 33 29 . 4 7 eS 4 3 69 . 8 7 rB 5 3 40 9 . 9 7 rK 6 3 08 . 3 8 b R 7 3 7 4 . 5 8 r S 8 3 2 6 . 7 8 Y 9 3 1 9 . 8 8 r Z 0 4 2 2 . 1 9 b N 1 4 1 9 . 2 9 oM 24 4 9 .5 9 c T 3 4 u R 4 4 7 0 . 1 0 1 h R 5 4 1 9 . 2 0 1 d P6 4 4. 6 0 1 g A 7 4 7 8 . 7 0 1 d C 8 4 0 4 . 2 1 1 n I 9 4 2 8 . 4 1 1n S 0 5 9 6 . 8 1 1 b S 1 5 5 7 . 1 2 1 e T 2 5 0 6 . 7 2 1 I 3 5 0 9 . 6 2 1 eX 4 5 0 3 . 1 3 1 sC 5 5 1 9 . 2 3 1 a B 6 5 4 3 . 7 3 1 * a L 7 5 1 9 . 8 3 1 f H 2 7 9 4 . 8 7 1 a T 3 7 5 9 . 0 8 1 W 4 7 5 8 . 3 8 1 e R 57 2 . 6 8 1 s O 6 7 2 . 0 9 1 r I 7 7 2. 2 9 1 t P 8 7 9 0 . 5 9 1 u A 9 7 7 9 . 6 9 1 g H 0 8 9 5 . 0 0 2 l T 1 8 73 .4 0 2 bP 2 8 2. 7 0 2 iB 3 8 89 . 8 0 2 oP 48 tA 58 nR 68 r F 7 8 aR 8 8 cA + 98 se d i n a h t n a L * e C 8 5 2 1 . 0 4 1 r P 9 5 1 9 . 0 4 1 d N 0 6 42 . 4 4 1 mP 16 m S 26 4. 0 5 1 u E 3 6 6 9 . 1 5 1 d G 4 6 5 2 . 7 5 1 b T 5 6 3 9 . 8 5 1 y D 6 6 0 5 . 2 6 1 o H 7 6 3 9 . 4 6 1 r E 8 6 6 2 . 7 6 1 m T 9 6 3 9 . 8 6 1 b Y 0 7 4 0 . 3 7 1uL 1 7 7 9 . 4 7 1 + s e d i n i t c A h T 0 9 10 . 2 3 2 aP 1 9 U 29 30 . 8 3 2 p N 39 uP 49 mA 59 mC 69 kB 79 fC 89 sE 99 mF 00 1 dM 10 1 oN 20 1 rL 30 1 121314 15 16 17345 6 7 8 9 10 11 1218The Mars Curiosity rover’s landing in August 2012 was achievedusing variable thrust mono propellant hydrazine rocket thrusters.Hydrazine, N2H4, is popular with NASA as it produces no carbondioxide.The hydrazine is passed over a suitable catalyst and decomposes toits elements. The rapid production of the hot gaseous elements iswhat provides the thrust. Ammonia can be formed as an intermediateduring the decomposition.(a) Write a balanced equation for hydrazine decomposing to ammonia and nitrogen gas.(b) Hydrazine may be obtained from the reaction between ammonia and hydrogen peroxide.2NH3(g) + H2O2(l) → N2H4(l) + 2H2O(l) ∆r H o = −241.0 kJ mol−1Work out the standard enthalpy change for the decomposition of hydrazine to its elements.The standard enthalpy changes of formation in kJ mol−1 are:NH3: −46.1; H2O2: −187.8; H2O: −285.8(c) The first ever rocket-powered fighter plane, the Messerschmitt Me 163, was powered by the reactionbetween a hydrazine-methanol mixture, known as ‘C-Stoff’, and hydrogen peroxide (‘T-Stoff’).(i)Hydrogen peroxide reacts with the hydrazine as shown in the equation.N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(l)State the oxidation number of nitrogen and oxygen in the reactants and products.(ii) Hydrogen peroxide oxidises the methanol to carbon dioxide and water.Write a balanced equation for this reaction.(iii) The fighter plane would hold 225 litres of hydrazine and 862 litres of methanol. Use the following standard enthalpy changes and densities to calculate the heat energy evolved under standardconditions for the combustion of this quantity of rocket fuel. Assume that all the hydrazine andmethanol are fully combusted.∆c H o (N2H4) = −622.2 kJ mol−1 Density of N2H4 = 1.021 g cm−3∆c H o (CH3OH) = −726.0 kJ mol−1 Density of CH3OH = 0.7918 g cm−3(d) Hydrazine is also commonly combined with dinitrogen tetroxide, N2O4, in rocket fuels. This forms ahypergolic mixture, i.e. the reactants ignite spontaneously on contact. NASA used N2H4 / N2O4 in many space vehicles and it is likely to be used in next-generation vehicles.(i) Reactions used in rocketry produce chemically stable products (making the reaction exothermic)that are formed as gases (which provide thrust). Suggest the reaction products that are formed in the reaction between N2H4 and N2O4.(ii) Pure N2O4, when warmed, initially decomposes not into its elements but instead forms a brown gas. Suggest the identity of this brown gas.(e) A derivative of hydrazine with formula C2H8N2 was used in rocket fuels in the Apollo missions. It hastwo nitrogen atoms that are in different chemical environments and two carbon atoms that are in thesame chemical environment. Draw the structure of C2H8N2.2. This question is about Great Britain being better than any other country at cyclingOne of the most successful British sportsat the London 2012 Olympics was cycling.British cyclists won eight gold, two silverand two bronze medals. In addition,Bradley Wiggins became the first everBriton to win the Tour de France.(a) Bronze medals contain copper. A 0.800 g sample of a bronze medal was dissolved in hotconcentrated nitric acid. After cooling and dilution, an excess of potassium iodide solution was added and the solution was made up to 250.0 cm3. A 25.00 cm3 aliquot of this solution required 12.20 cm3 of0.100 mol dm−3 sodium thiosulfate solution in the presence of starch indicator.Calculate the percentage by mass of copper in the bronze medal.2Cu2+(aq) + 4I−(aq) → 2CuI(s) + I2(aq)I2(aq) + 2S2O32−(aq) → 2I−(aq) + S4O62−(aq)(b) All medals that were won at London 2012 had a diameter of 85 mm and were 7 mm thick. The silvermedal was made up of 92.5% silver and 7.5% copper, by mass.Calculate the mass of a silver medal. Assume that the density of the alloy varies proportionally to its composition by mass.Densities in g cm−3: Ag, 10.49; Cu, 8.96(c) Gold medals are made of gold, silver and copper. A 5.000 g sample of a gold medal was warmed withexcess concentrated nitric acid. An undissolved residue was separated by filtration, washed, dried and weighed. Its mass was 0.067 g. Then an excess of dilute hydrochloric acid was added to the solution in nitric acid. The precipitate formed was separated by filtration, washed, dried and weighed.Its mass was 6.144 g.Calculate the percentage by mass of gold, silver and copper in the gold medal.The GB cyclists have individually designed bikes, which have to cope with the demands placed on them whilst being as light as possible. One way a light bike could be achieved is by altering the gas used to inflate the bike tyres.You may assume that for the remainder of this question that gases behave as ideal gases and that they follow the ideal gas law:pV = nRTwhere p = pressure in PaV = volume in m3n = number of molesR (the gas constant) = 8.31 J K−1 mol−1T = temperature in KelvinThe tyres on a bike are approximately theshape of a torus. The equation for thevolume of a torus, V, is given below.V = π2rd2 2r = distance from centre of torus tocentre of tyre tubed = diameter of tyre tube(d) A typical bike may have a wheel diameter of 66 cm and a tyre diameter of 23 mm.Calculate the volume of a tyre, in m3.If you are unable to calculate the volume of a tyre, you may use the value of 0.001 m3 in the subsequent parts of this question.(e) (i) The air pressure used in the tyres is typically 120 psi, much higher than atmospheric pressure.1 psi = 6895 Pa.Calculate the number of moles of gas in a tyre, at 25 °C.(ii) Assuming air is a mixture of 80 % nitrogen gas and 20 % oxygen gas, calculate the total mass of air in both tyres on a bike.(iii) In cycling the smallest of changes can make the difference between winning and losing. The small reduction in mass upon inflating tyres with helium instead of air would be worth considering if it was not for that fact that the very small helium atoms escape through the rubber of tyres much more rapidly.Calculate the reduction in mass of the bike if both tyres were inflated with helium instead of air.(iv) SF6 is one of the densest substances that would still remain in the gas phase at this pressure.What would be the increase in mass if the bike tyres were filled with SF6?3. This question is about chemistry general knowledge based on coloured compoundsChemists recognise many substances by their colour.This question tests your knowledge about the colour of arange of chemicals that you will have come across aspart of your studies of chemistry.(a) In the answer booklet, a number of colours are listed. For each colour, if one of the substances belowis that colour, give its letter. If that colour cannot be made using a single substance, give the letters of two substances that will produce this colour when mixed. A substance may be used more than once.Choose from A = CaCl2(s) F = FeSO4.7H2O(s)B = CuO(s) G = K2Cr2O7(s)C = Cu2O(s) H = NaOH(aq)D = CuSO4(s) I = VSO4.7H2O(s)E = Al2O3(s) J = ZnCl2(s)(b) A student was provided with 7 unknown aqueous solutions. Each solution contained only onesubstance and all solutions were different.The student mixed pairs of solutions in an attempt to identify each of the substances. The results from these tests are shown below. A blank cell shows where no observable results were obtained.Analyse the results and assign the following substances as solutions T-Z.barium chloride dissolved chlorine gas(i.e. chlorine water)iron(II) sulfate lead(II) nitrate silver nitrate sodium carbonate sodium iodideT U V W X Y ZT Bright yellowprecipitate formed White precipitateformed–White precipitateformedWhite precipitateformedWhite precipitateformedU Bright yellowprecipitate formed –Yellow precipitateformed– – Brown solutionV White precipitateformed –White precipitateformed (darkenedin daylight)White precipitateformedWhite precipitateformed–W – Yellow precipitateformed White precipitateformed (darkenedin daylight)Off-whiteprecipitate formedWhite precipitateformedWhite precipitateformed (darkenedin daylight)X White precipitateformed –White precipitateformedOff-whiteprecipitate formedDirty greenprecipitate formed(turned brown onstanding)–Y White precipitateformed –White precipitateformedWhite precipitateformedDirty greenprecipitate formed(turned brown onstanding)Pale yellowsolutionZ White precipitateformed Brown solution –White precipitateformed (darkenedin daylight)–Pale yellowsolution4. This question is about GPs giving out too many drugsThe drugs diazepam (Valium®) and alprazolam (Xanax®)belong to a family of compounds called benzodiazepineswhich were once hailed as the answer to many ailments. In1988, The Committee on Safety of Medicines advised GPs tolimit their prescriptions of these drugs due to their overuse;however, in England in 2010 more than 6.6 millionbenzodiazepine prescriptions for anxiety were dispensed.Heath Ledger, Michael Jackson and Whitney Houston areamong some of the many people that are believed to havedied from drug overdoses that involved benzodiazepines.The synthesis of diazepam from 4-chloroaniline is shown below. The percentage yield for each step is also shown. By-products are not always shown.(a) (i) Calculate the overall percentage yield for the conversion of 4-chloroaniline to diazepam.(ii) A patient was prescribed diazepam for three years at a dose of 5 mg, four times a day.Calculate the mass of diazepam this was, and hence the mass of 4-chloroaniline needed to make the drug for this patient.(b) Draw the structures of intermediates A – H in the synthesis of diazepam.In the liver it was found that diazepam underwent a demethylation reaction. The product of this demethylation reaction was used as inspiration for the synthesis of the drug alprazolam.(c) The synthesis of alprazolam is shown below. Draw the structures of intermediates I , J and K(d) In the final stage of the synthesis, compound L is treated with achemical called ‘DEAD’ to convert it into alprazolam. DEAD stands for diethyl azodicarboxylate.How would you classify the reaction of L to alprazolam using one of the terms below?Tick the correct answer in your answer booklet.Isomerisation Hydrolysis Condensation Oxidation Reduction5. This question is about getting big musclesCreatine has recently become one of the most widely used nutritional supplements among athletes. Although there is much debate aboutwhich of the advertised beneficial effects of creatine are actually true, the use of creatine is generally believed to lead to a short-term gain in body mass/muscle size. The structure of creatine is shown below.In the body, creatine is converted into phosphocreatine which is used as an energy reserve in the muscles that can be rapidly mobilised toconvert adenosine diphosphate (ADP) back into adenosine triphosphate (ATP) – the body’s energy currency – in times of need.(a) Creatine is often sold in capsules labelled as ‘Pure Creatine Monohydrate’.Write the molecular formula of creatine monohydrate.(b) Creatine is synthesised naturally in organisms from three amino acids: glycine, methionine andarginine.In your answer booklet, for each of the carbon atoms in creatine (labelled as 1-4), suggest which carbon atom of the three amino acids it came from (labelled as A-M )(c) Like amino acids, creatine exists in different ionised forms depending on the pH of the solution it is in.This causes the overall charge on the molecule to vary. Draw the most common form of creatine at each of the following pHs (the overall charge on the molecule at each pH is given).(i) pH 1 (overall charge = + 1) (ii) pH 7 (overall charge = neutral)(iii) pH 12(overall charge = − 1)The chemical structure of creatine and these amino acids can be analysed by 1H NMR.As these are polar molecules, the NMR spectra are run in D 2O solvent. In D 2O, protons attached tonitrogen or oxygen atoms undergo rapid exchange with deuteriums from the solvent. This means that by the time the NMR is run, all N-H bonds have been replaced by N-D bonds and all O-H bonds by O-Dbonds. As signals from deuterium atoms are not observed in 1H NMR spectra, no signals from N-H or O-H groups in the molecule are seen in the spectrum.The number of signals observed depends on the symmetry of the molecule. Each hydrogen atom in a unique environment gives rise to a signal at a different chemical shift in the spectrum. Occasionally,signals from two different environments can appear on top of one another when the difference in chemical shifts between the environments is very small.The area under each signal is proportional to the number of protons in that environment. This is shown by an integral trace (the stepped line on the spectrum). The height of each step is proportional to the areaunder that signal.The appearance of the signals can be complicated by coupling. If thehydrogen atom(s) are within three bonds of another hydrogen which is in adifferent environment, instead of appearing as a single peak, its signal issplit into a number of peaks. If the hydrogen under consideration is withinthree bonds of n hydrogens in a different environment from itself, it will be split into (n + 1) equally spaced peaks. The ratio of the area under the peaks is given by the number in Pascal’s triangle (shown on the right). Due to rapid exchange of any protons/deuteriums bonded to oxygen or nitrogen atoms with the solvent, no coupling is seen to protons/deuteriums bonded to oxygen or nitrogen atoms.n Intensities of peaks 0 1 1 1 : 1 2 1 : 2 : 1 3 1 : 3 : 3 : 1 4 1 : 4 : 6 : 4 : 1 (d) Consider the amino acid methionine.Complete the table in the answer booklet for carbons C , D and F inmethionine to suggest the appearance of the overall signal from the protons bonded to that carbon atom.(e) Usually all protons attached to the same carbon atom are in the same chemical environment;however, this is not always the case. Two protons on the same carbon atom that are in different chemical environments are called diastereotopic protons.These are most often observed where the carbon under consideration is bonded to an asymmetric carbon atom. An asymmetric carbon atom has four different chemical groups attached to it.Consider glycine, methionine and arginine. In these three amino acids, write the letters of all such carbons whose diastereotopic protons would be observed as different signals in their spectra.In the body, creatine is in equilibrium with a cyclic molecule called creatinine, by the following equation. The position of equilibrium varies with pH.Creatinine is a metabolic waste product that is not used by the body. It is filtered out in the kidneys.The 1H NMR spectrum in D 2O of a creatine/creatinine solution is shown below. Three signals areobserved. Creatinine gives rise to signal A. Creatine gives rise to signal B. Both creatine and creatinine give rise to signal C.(f) Suggest a structure for creatinine.(g) Assuming this sample has reached equilibrium, calculate a value for the equilibrium constant, K, atthis pH and temperature. Show clearly how you worked this out. You may ignore the concentration of water in your calculation.(h) A problem with creatine supplementation is that a lot of the creatine taken does not get absorbed bythe body. Recently, supplements containing derivatives of creatine have been marketed. These are usually more lipophilic (dissolve more easily in fats) in an effort to improve uptake into the body.The 1H NMR spectrum in D2O of one of these supplements is shown below. Some regions of the spectrum have been expanded on the left hand side of the figure to help with your analysis.This supplement exists in an ionised form at pH 1 but does not exist in an ionised form at pH 12.Suggest a structure for this supplement.Acknowledgements & ReferencesQ1The Curiosity Mars rover image is courtesy of NASA.Q2Information on the composition of the medals was taken from .The Bradley Wiggins image is courtesy of Getty Images.Q3The image of the test tubes is courtesy of iStockphoto.Q4The Independent Thursday 29th December 2011 Doctors sued for creating 'Valium addicts'Nina Lakhani The image of diazepam is courtesy of Paul Brown and Alamy.Heterocycles 198116 1491-1494Journal of Medicinal Chemistry 197720 1694-1697Journal of Medicinal Chemistry 197922 1-7Journal of Organic Chemistry 198045 1675-1681Tetrahedron Letters 197112 1609-1612Q5John Gallacher is thanked for providing an image of his arm.The University of Oxford is thanked for use of their NMR facilities.The creatine supplements analysed were from Precision Engineered Ltd.Biochemical Journal 192822 920-929Journal of the Chemical Society, Perkin Transactions II 1985 1465-1467The UK Chemistry Olympiad is supported by INEOS. INEOS is a leadingglobal manufacturer of petrochemicals, specialty chemicals and oilproducts. It comprises 19 businesses each with a major chemical companyheritage. The production network spans 73 manufacturing facilities in 19countries throughout the world. The chemicals INEOS produce enhancealmost every aspect of modern life.。
物理学专业英语
华中师范大学物理学院物理学专业英语仅供内部学习参考！2014一、课程的任务和教学目的通过学习《物理学专业英语》，学生将掌握物理学领域使用频率较高的专业词汇和表达方法，进而具备基本的阅读理解物理学专业文献的能力。
通过分析《物理学专业英语》课程教材中的范文，学生还将从英语角度理解物理学中个学科的研究内容和主要思想，提高学生的专业英语能力和了解物理学研究前沿的能力。
培养专业英语阅读能力，了解科技英语的特点，提高专业外语的阅读质量和阅读速度；掌握一定量的本专业英文词汇，基本达到能够独立完成一般性本专业外文资料的阅读；达到一定的笔译水平。
要求译文通顺、准确和专业化。
要求译文通顺、准确和专业化。
二、课程内容课程内容包括以下章节：物理学、经典力学、热力学、电磁学、光学、原子物理、统计力学、量子力学和狭义相对论三、基本要求1.充分利用课内时间保证充足的阅读量（约1200~1500词/学时），要求正确理解原文。
2.泛读适量课外相关英文读物，要求基本理解原文主要内容。
3.掌握基本专业词汇（不少于200词）。
4.应具有流利阅读、翻译及赏析专业英语文献，并能简单地进行写作的能力。
四、参考书目录1 Physics 物理学 (1)Introduction to physics (1)Classical and modern physics (2)Research fields (4)V ocabulary (7)2 Classical mechanics 经典力学 (10)Introduction (10)Description of classical mechanics (10)Momentum and collisions (14)Angular momentum (15)V ocabulary (16)3 Thermodynamics 热力学 (18)Introduction (18)Laws of thermodynamics (21)System models (22)Thermodynamic processes (27)Scope of thermodynamics (29)V ocabulary (30)4 Electromagnetism 电磁学 (33)Introduction (33)Electrostatics (33)Magnetostatics (35)Electromagnetic induction (40)V ocabulary (43)5 Optics 光学 (45)Introduction (45)Geometrical optics (45)Physical optics (47)Polarization (50)V ocabulary (51)6 Atomic physics 原子物理 (52)Introduction (52)Electronic configuration (52)Excitation and ionization (56)V ocabulary (59)7 Statistical mechanics 统计力学 (60)Overview (60)Fundamentals (60)Statistical ensembles (63)V ocabulary (65)8 Quantum mechanics 量子力学 (67)Introduction (67)Mathematical formulations (68)Quantization (71)Wave-particle duality (72)Quantum entanglement (75)V ocabulary (77)9 Special relativity 狭义相对论 (79)Introduction (79)Relativity of simultaneity (80)Lorentz transformations (80)Time dilation and length contraction (81)Mass-energy equivalence (82)Relativistic energy-momentum relation (86)V ocabulary (89)正文标记说明：蓝色Arial字体（例如energy）：已知的专业词汇蓝色Arial字体加下划线（例如electromagnetism）：新学的专业词汇黑色Times New Roman字体加下划线（例如postulate）：新学的普通词汇1 Physics 物理学1 Physics 物理学Introduction to physicsPhysics is a part of natural philosophy and a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy. Over the last two millennia, physics was a part of natural philosophy along with chemistry, certain branches of mathematics, and biology, but during the Scientific Revolution in the 17th century, the natural sciences emerged as unique research programs in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry,and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms of other sciences, while opening new avenues of research in areas such as mathematics and philosophy.Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs. For example, advances in the understanding of electromagnetism or nuclear physics led directly to the development of new products which have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.Core theoriesThough physics deals with a wide variety of systems, certain theories are used by all physicists. Each of these theories were experimentally tested numerous times and found correct as an approximation of nature (within a certain domain of validity).For instance, the theory of classical mechanics accurately describes the motion of objects, provided they are much larger than atoms and moving at much less than the speed of light. These theories continue to be areas of active research, and a remarkable aspect of classical mechanics known as chaos was discovered in the 20th century, three centuries after the original formulation of classical mechanics by Isaac Newton (1642–1727) 【艾萨克·牛顿】.University PhysicsThese central theories are important tools for research into more specialized topics, and any physicist, regardless of his or her specialization, is expected to be literate in them. These include classical mechanics, quantum mechanics, thermodynamics and statistical mechanics, electromagnetism, and special relativity.Classical and modern physicsClassical mechanicsClassical physics includes the traditional branches and topics that were recognized and well-developed before the beginning of the 20th century—classical mechanics, acoustics, optics, thermodynamics, and electromagnetism.Classical mechanics is concerned with bodies acted on by forces and bodies in motion and may be divided into statics (study of the forces on a body or bodies at rest), kinematics (study of motion without regard to its causes), and dynamics (study of motion and the forces that affect it); mechanics may also be divided into solid mechanics and fluid mechanics (known together as continuum mechanics), the latter including such branches as hydrostatics, hydrodynamics, aerodynamics, and pneumatics.Acoustics is the study of how sound is produced, controlled, transmitted and received. Important modern branches of acoustics include ultrasonics, the study of sound waves of very high frequency beyond the range of human hearing; bioacoustics the physics of animal calls and hearing, and electroacoustics, the manipulation of audible sound waves using electronics.Optics, the study of light, is concerned not only with visible light but also with infrared and ultraviolet radiation, which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light.Heat is a form of energy, the internal energy possessed by the particles of which a substance is composed; thermodynamics deals with the relationships between heat and other forms of energy.Electricity and magnetism have been studied as a single branch of physics since the intimate connection between them was discovered in the early 19th century; an electric current gives rise to a magnetic field and a changing magnetic field induces an electric current. Electrostatics deals with electric charges at rest, electrodynamics with moving charges, and magnetostatics with magnetic poles at rest.Modern PhysicsClassical physics is generally concerned with matter and energy on the normal scale of1 Physics 物理学observation, while much of modern physics is concerned with the behavior of matter and energy under extreme conditions or on the very large or very small scale.For example, atomic and nuclear physics studies matter on the smallest scale at which chemical elements can be identified.The physics of elementary particles is on an even smaller scale, as it is concerned with the most basic units of matter; this branch of physics is also known as high-energy physics because of the extremely high energies necessary to produce many types of particles in large particle accelerators. On this scale, ordinary, commonsense notions of space, time, matter, and energy are no longer valid.The two chief theories of modern physics present a different picture of the concepts of space, time, and matter from that presented by classical physics.Quantum theory is concerned with the discrete, rather than continuous, nature of many phenomena at the atomic and subatomic level, and with the complementary aspects of particles and waves in the description of such phenomena.The theory of relativity is concerned with the description of phenomena that take place in a frame of reference that is in motion with respect to an observer; the special theory of relativity is concerned with relative uniform motion in a straight line and the general theory of relativity with accelerated motion and its connection with gravitation.Both quantum theory and the theory of relativity find applications in all areas of modern physics.Difference between classical and modern physicsWhile physics aims to discover universal laws, its theories lie in explicit domains of applicability. Loosely speaking, the laws of classical physics accurately describe systems whose important length scales are greater than the atomic scale and whose motions are much slower than the speed of light. Outside of this domain, observations do not match their predictions.Albert Einstein【阿尔伯特·爱因斯坦】contributed the framework of special relativity, which replaced notions of absolute time and space with space-time and allowed an accurate description of systems whose components have speeds approaching the speed of light.Max Planck【普朗克】, Erwin Schrödinger【薛定谔】, and others introduced quantum mechanics, a probabilistic notion of particles and interactions that allowed an accurate description of atomic and subatomic scales.Later, quantum field theory unified quantum mechanics and special relativity.General relativity allowed for a dynamical, curved space-time, with which highly massiveUniversity Physicssystems and the large-scale structure of the universe can be well-described. General relativity has not yet been unified with the other fundamental descriptions; several candidate theories of quantum gravity are being developed.Research fieldsContemporary research in physics can be broadly divided into condensed matter physics; atomic, molecular, and optical physics; particle physics; astrophysics; geophysics and biophysics. Some physics departments also support research in Physics education.Since the 20th century, the individual fields of physics have become increasingly specialized, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) and Lev Landau (1908–1968)【列夫·朗道】, who worked in multiple fields of physics, are now very rare.Condensed matter physicsCondensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. In particular, it is concerned with the "condensed" phases that appear whenever the number of particles in a system is extremely large and the interactions between them are strong.The most familiar examples of condensed phases are solids and liquids, which arise from the bonding by way of the electromagnetic force between atoms. More exotic condensed phases include the super-fluid and the Bose–Einstein condensate found in certain atomic systems at very low temperature, the superconducting phase exhibited by conduction electrons in certain materials,and the ferromagnetic and antiferromagnetic phases of spins on atomic lattices.Condensed matter physics is by far the largest field of contemporary physics.Historically, condensed matter physics grew out of solid-state physics, which is now considered one of its main subfields. The term condensed matter physics was apparently coined by Philip Anderson when he renamed his research group—previously solid-state theory—in 1967. In 1978, the Division of Solid State Physics of the American Physical Society was renamed as the Division of Condensed Matter Physics.Condensed matter physics has a large overlap with chemistry, materials science, nanotechnology and engineering.Atomic, molecular and optical physicsAtomic, molecular, and optical physics (AMO) is the study of matter–matter and light–matter interactions on the scale of single atoms and molecules.1 Physics 物理学The three areas are grouped together because of their interrelationships, the similarity of methods used, and the commonality of the energy scales that are relevant. All three areas include both classical, semi-classical and quantum treatments; they can treat their subject from a microscopic view (in contrast to a macroscopic view).Atomic physics studies the electron shells of atoms. Current research focuses on activities in quantum control, cooling and trapping of atoms and ions, low-temperature collision dynamics and the effects of electron correlation on structure and dynamics. Atomic physics is influenced by the nucleus (see, e.g., hyperfine splitting), but intra-nuclear phenomena such as fission and fusion are considered part of high-energy physics.Molecular physics focuses on multi-atomic structures and their internal and external interactions with matter and light.Optical physics is distinct from optics in that it tends to focus not on the control of classical light fields by macroscopic objects, but on the fundamental properties of optical fields and their interactions with matter in the microscopic realm.High-energy physics (particle physics) and nuclear physicsParticle physics is the study of the elementary constituents of matter and energy, and the interactions between them.In addition, particle physicists design and develop the high energy accelerators,detectors, and computer programs necessary for this research. The field is also called "high-energy physics" because many elementary particles do not occur naturally, but are created only during high-energy collisions of other particles.Currently, the interactions of elementary particles and fields are described by the Standard Model.●The model accounts for the 12 known particles of matter (quarks and leptons) thatinteract via the strong, weak, and electromagnetic fundamental forces.●Dynamics are described in terms of matter particles exchanging gauge bosons (gluons,W and Z bosons, and photons, respectively).●The Standard Model also predicts a particle known as the Higgs boson. In July 2012CERN, the European laboratory for particle physics, announced the detection of a particle consistent with the Higgs boson.Nuclear Physics is the field of physics that studies the constituents and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those in nuclear medicine and magnetic resonance imaging, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology.University PhysicsAstrophysics and Physical CosmologyAstrophysics and astronomy are the application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. Because astrophysics is a broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.The discovery by Karl Jansky in 1931 that radio signals were emitted by celestial bodies initiated the science of radio astronomy. Most recently, the frontiers of astronomy have been expanded by space exploration. Perturbations and interference from the earth's atmosphere make space-based observations necessary for infrared, ultraviolet, gamma-ray, and X-ray astronomy.Physical cosmology is the study of the formation and evolution of the universe on its largest scales. Albert Einstein's theory of relativity plays a central role in all modern cosmological theories. In the early 20th century, Hubble's discovery that the universe was expanding, as shown by the Hubble diagram, prompted rival explanations known as the steady state universe and the Big Bang.The Big Bang was confirmed by the success of Big Bang nucleo-synthesis and the discovery of the cosmic microwave background in 1964. The Big Bang model rests on two theoretical pillars: Albert Einstein's general relativity and the cosmological principle (On a sufficiently large scale, the properties of the Universe are the same for all observers). Cosmologists have recently established the ΛCDM model (the standard model of Big Bang cosmology) of the evolution of the universe, which includes cosmic inflation, dark energy and dark matter.Current research frontiersIn condensed matter physics, an important unsolved theoretical problem is that of high-temperature superconductivity. Many condensed matter experiments are aiming to fabricate workable spintronics and quantum computers.In particle physics, the first pieces of experimental evidence for physics beyond the Standard Model have begun to appear. Foremost among these are indications that neutrinos have non-zero mass. These experimental results appear to have solved the long-standing solar neutrino problem, and the physics of massive neutrinos remains an area of active theoretical and experimental research. Particle accelerators have begun probing energy scales in the TeV range, in which experimentalists are hoping to find evidence for the super-symmetric particles, after discovery of the Higgs boson.Theoretical attempts to unify quantum mechanics and general relativity into a single theory1 Physics 物理学of quantum gravity, a program ongoing for over half a century, have not yet been decisively resolved. The current leading candidates are M-theory, superstring theory and loop quantum gravity.Many astronomical and cosmological phenomena have yet to be satisfactorily explained, including the existence of ultra-high energy cosmic rays, the baryon asymmetry, the acceleration of the universe and the anomalous rotation rates of galaxies.Although much progress has been made in high-energy, quantum, and astronomical physics, many everyday phenomena involving complexity, chaos, or turbulence are still poorly understood. Complex problems that seem like they could be solved by a clever application of dynamics and mechanics remain unsolved; examples include the formation of sand-piles, nodes in trickling water, the shape of water droplets, mechanisms of surface tension catastrophes, and self-sorting in shaken heterogeneous collections.These complex phenomena have received growing attention since the 1970s for several reasons, including the availability of modern mathematical methods and computers, which enabled complex systems to be modeled in new ways. Complex physics has become part of increasingly interdisciplinary research, as exemplified by the study of turbulence in aerodynamics and the observation of pattern formation in biological systems.Vocabulary★natural science 自然科学academic disciplines 学科astronomy 天文学in their own right 凭他们本身的实力intersects相交，交叉interdisciplinary交叉学科的，跨学科的★quantum 量子的theoretical breakthroughs 理论突破★electromagnetism 电磁学dramatically显著地★thermodynamics热力学★calculus微积分validity★classical mechanics 经典力学chaos 混沌literate 学者★quantum mechanics量子力学★thermodynamics and statistical mechanics热力学与统计物理★special relativity狭义相对论is concerned with 关注，讨论，考虑acoustics 声学★optics 光学statics静力学at rest 静息kinematics运动学★dynamics动力学ultrasonics超声学manipulation 操作，处理，使用University Physicsinfrared红外ultraviolet紫外radiation辐射reflection 反射refraction 折射★interference 干涉★diffraction 衍射dispersion散射★polarization 极化，偏振internal energy 内能Electricity电性Magnetism 磁性intimate 亲密的induces 诱导，感应scale尺度★elementary particles基本粒子★high-energy physics 高能物理particle accelerators 粒子加速器valid 有效的，正当的★discrete离散的continuous 连续的complementary 互补的★frame of reference 参照系★the special theory of relativity 狭义相对论★general theory of relativity 广义相对论gravitation 重力，万有引力explicit 详细的，清楚的★quantum field theory 量子场论★condensed matter physics凝聚态物理astrophysics天体物理geophysics地球物理Universalist博学多才者★Macroscopic宏观Exotic奇异的★Superconducting 超导Ferromagnetic铁磁质Antiferromagnetic 反铁磁质★Spin自旋Lattice 晶格，点阵，网格★Society社会，学会★microscopic微观的hyperfine splitting超精细分裂fission分裂，裂变fusion熔合，聚变constituents成分，组分accelerators加速器detectors 检测器★quarks夸克lepton 轻子gauge bosons规范玻色子gluons胶子★Higgs boson希格斯玻色子CERN欧洲核子研究中心★Magnetic Resonance Imaging磁共振成像，核磁共振ion implantation 离子注入radiocarbon dating放射性碳年代测定法geology地质学archaeology考古学stellar 恒星cosmology宇宙论celestial bodies 天体Hubble diagram 哈勃图Rival竞争的★Big Bang大爆炸nucleo-synthesis核聚合，核合成pillar支柱cosmological principle宇宙学原理ΛCDM modelΛ-冷暗物质模型cosmic inflation宇宙膨胀1 Physics 物理学fabricate制造，建造spintronics自旋电子元件，自旋电子学★neutrinos 中微子superstring 超弦baryon重子turbulence湍流，扰动，骚动catastrophes突变，灾变，灾难heterogeneous collections异质性集合pattern formation模式形成University Physics2 Classical mechanics 经典力学IntroductionIn physics, classical mechanics is one of the two major sub-fields of mechanics, which is concerned with the set of physical laws describing the motion of bodies under the action of a system of forces. The study of the motion of bodies is an ancient one, making classical mechanics one of the oldest and largest subjects in science, engineering and technology.Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. Besides this, many specializations within the subject deal with gases, liquids, solids, and other specific sub-topics.Classical mechanics provides extremely accurate results as long as the domain of study is restricted to large objects and the speeds involved do not approach the speed of light. When the objects being dealt with become sufficiently small, it becomes necessary to introduce the other major sub-field of mechanics, quantum mechanics, which reconciles the macroscopic laws of physics with the atomic nature of matter and handles the wave–particle duality of atoms and molecules. In the case of high velocity objects approaching the speed of light, classical mechanics is enhanced by special relativity. General relativity unifies special relativity with Newton's law of universal gravitation, allowing physicists to handle gravitation at a deeper level.The initial stage in the development of classical mechanics is often referred to as Newtonian mechanics, and is associated with the physical concepts employed by and the mathematical methods invented by Newton himself, in parallel with Leibniz【莱布尼兹】, and others.Later, more abstract and general methods were developed, leading to reformulations of classical mechanics known as Lagrangian mechanics and Hamiltonian mechanics. These advances were largely made in the 18th and 19th centuries, and they extend substantially beyond Newton's work, particularly through their use of analytical mechanics. Ultimately, the mathematics developed for these were central to the creation of quantum mechanics.Description of classical mechanicsThe following introduces the basic concepts of classical mechanics. For simplicity, it often2 Classical mechanics 经典力学models real-world objects as point particles, objects with negligible size. The motion of a point particle is characterized by a small number of parameters: its position, mass, and the forces applied to it.In reality, the kind of objects that classical mechanics can describe always have a non-zero size. (The physics of very small particles, such as the electron, is more accurately described by quantum mechanics). Objects with non-zero size have more complicated behavior than hypothetical point particles, because of the additional degrees of freedom—for example, a baseball can spin while it is moving. However, the results for point particles can be used to study such objects by treating them as composite objects, made up of a large number of interacting point particles. The center of mass of a composite object behaves like a point particle.Classical mechanics uses common-sense notions of how matter and forces exist and interact. It assumes that matter and energy have definite, knowable attributes such as where an object is in space and its speed. It also assumes that objects may be directly influenced only by their immediate surroundings, known as the principle of locality.In quantum mechanics objects may have unknowable position or velocity, or instantaneously interact with other objects at a distance.Position and its derivativesThe position of a point particle is defined with respect to an arbitrary fixed reference point, O, in space, usually accompanied by a coordinate system, with the reference point located at the origin of the coordinate system. It is defined as the vector r from O to the particle.In general, the point particle need not be stationary relative to O, so r is a function of t, the time elapsed since an arbitrary initial time.In pre-Einstein relativity (known as Galilean relativity), time is considered an absolute, i.e., the time interval between any given pair of events is the same for all observers. In addition to relying on absolute time, classical mechanics assumes Euclidean geometry for the structure of space.Velocity and speedThe velocity, or the rate of change of position with time, is defined as the derivative of the position with respect to time. In classical mechanics, velocities are directly additive and subtractive as vector quantities; they must be dealt with using vector analysis.When both objects are moving in the same direction, the difference can be given in terms of speed only by ignoring direction.University PhysicsAccelerationThe acceleration , or rate of change of velocity, is the derivative of the velocity with respect to time (the second derivative of the position with respect to time).Acceleration can arise from a change with time of the magnitude of the velocity or of the direction of the velocity or both . If only the magnitude v of the velocity decreases, this is sometimes referred to as deceleration , but generally any change in the velocity with time, including deceleration, is simply referred to as acceleration.Inertial frames of referenceWhile the position and velocity and acceleration of a particle can be referred to any observer in any state of motion, classical mechanics assumes the existence of a special family of reference frames in terms of which the mechanical laws of nature take a comparatively simple form. These special reference frames are called inertial frames .An inertial frame is such that when an object without any force interactions (an idealized situation) is viewed from it, it appears either to be at rest or in a state of uniform motion in a straight line. This is the fundamental definition of an inertial frame. They are characterized by the requirement that all forces entering the observer's physical laws originate in identifiable sources (charges, gravitational bodies, and so forth).A non-inertial reference frame is one accelerating with respect to an inertial one, and in such a non-inertial frame a particle is subject to acceleration by fictitious forces that enter the equations of motion solely as a result of its accelerated motion, and do not originate in identifiable sources. These fictitious forces are in addition to the real forces recognized in an inertial frame.A key concept of inertial frames is the method for identifying them. For practical purposes, reference frames that are un-accelerated with respect to the distant stars are regarded as good approximations to inertial frames.Forces; Newton's second lawNewton was the first to mathematically express the relationship between force and momentum . Some physicists interpret Newton's second law of motion as a definition of force and mass, while others consider it a fundamental postulate, a law of nature. Either interpretation has the same mathematical consequences, historically known as "Newton's Second Law":a m t v m t p F ===d )(d d dThe quantity m v is called the (canonical ) momentum . The net force on a particle is thus equal to rate of change of momentum of the particle with time.So long as the force acting on a particle is known, Newton's second law is sufficient to。
Physics Challenge英国物理挑战杯-2010-QuestionPaper问卷
NameSchool2010 Physics ChallengeTime allowed: 1 hourAttempt all questions. Write your answers on this question paper.You may use any calculator.Assume the gravitational field strength has a value of g = 10 N/kgSection A: Ten multiple choice questions worth 1 mark each (worth 10 marks in total).Allow about 10 minutes for this section.Section B: Two short answer questions (worth 8 marks in total).Questions require a clear explanation of the underlying physical principles.Allow about 10 minutes for this section.Section C: Longer answer questions requiring calculation (worth 32 marks in total).Questions may be set on unfamiliar topics. Additional information necessary to answerthe question will be given in the question.Allow about 40 minutes for this section.Total 50 marks; mark allocations for each sub-section are shown in brackets.Section A: Multiple Choice AnswersWrite the correct letter in the grid. The first column has been done as an example if the answer to question zero were CQuestion 0 1 2 3 4 5 6 7 8 9 10 Answer CB R I T I S H P H Y S IC S O L Y M P I A D1. The Earth is a distance of 1 Astronomical Unit (1 AU) from the Sun.In these units the speed of the Earth in its orbit around the Sun is:A. 1.00 AU / yearB. 2π AU / weekC. 0.017 AU / dayD. 0.26 AU / hourE. 1.99 x 10-7 AU / min2. A radioactive isotope with a short half life can be added to a batch of paint.The paint is stirred thoroughly and the activity of different samples is then measured to ensure they have been properly mixed.A radioisotope with a half life of 6 hours and an initial activity of 800 Bq is added to 500 litres ofpaint. If the paint is mixed evenly then after one day the activity of 1 litre of paint should be:A. 133 BqB. 50 BqC. 1.6 BqD. 0.2 BqE. 0.1 Bq3. The specific heat capacity (SHC) of a material is defined as the amount of energy required to raisethe temperature of 1 kg of the material by 1°C.When 1000 J of thermal energy is transferred to 200 g of material X the temperature increases by4 °C. When 2000 J of thermal energy is transferred to 100 g of material Y the temperatureincreases by 8 °C.The ratio of their specific heat capacities, SHC of X : SHC of Y is:A. 4 : 1B. 2 : 1C. 1 : 1D. 1 : 2E. 1 : 44. Consider the circuits shown below.In which circuit is the current flowing through the cell the largest?5. The 3rd floor observation deck of the Eiffel tower is about 280 m above street level.Assuming that the acceleration due to gravity is 10 m/s2 and that air resistance can be ignored, the speed of a coin dropped off the observation deck when it hits the streetbelow is:A. 280 m/sB. 75 m/sC. 28 m/sD. 10 m/sE. Cannot be determined without knowing the mass of the coin6. Microwaves and radiowaves can both used to transfer data from one place to another.The advantage of using microwaves is that they:A. are not diffractedB. travel fasterC. can transfer more information per secondD. have a longer wavelengthE. are not absorbed by the atmosphere7. A current carrying conductor (i.e. a wire) in a magnetic field experiences a force.Which of the following factors does NOT affect the size of the force.A. The size of the currentB. The strength of the magnetic fieldC. The angle between the conductor and the direction of the magneticfieldD. The length of the conductor in the magnetic fieldE. The direction of the current8. A uniform ruler is 100 cm long. A 0.6 N weight is placed at the 80 cm mark.The ruler is balanced in equilibrium on a pivot placed at the 60 cm mark.The weight of the ruler is:A. 1.2 NB. 1.0 NC. 0.6 ND. 0.5 NE. 0.3 N9. A frictionless trolley accelerates down a smooth straight sloping runway.When the mass of the trolley is doubled, the acceleration:A. DoublesB. Increases a bit but does not doubleC. Stays the sameD. Decreases a bit but does not halveE. Halves10. To measure the value of a fixed resistor, readings of voltage and current can be taken and theresistance calculated from these.The method likely to give the most accurate answer is:A. Carefully take a single reading of V and I and use the equation V = IR tocalculate resistance.B. Take several different readings of V and I, calculate R for each and takean average.C. Take several different readings of V and I, plot a graph of V against I andfind R from the gradientD. Assume that the value stated by the manufacturer is accurate as theyhave obviously tested all their resistorsE. Look it up on the internetSection B: Short answer questions11. Heat loss from a house can be reduced by using double glazing.Explain how double glazing reduces heat loss from a warm room to the colder outsideenvironment.................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (4)12. An electric light bulb is connected to a suitable power supply.The current flowing through the bulb quickly rises to a maximum when the power supply is first connected but then falls to settle at a lower constant value after a short time.Explain why the constant current flowing in the bulb is less than the maximum value................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (4)Section C: Longer questions13. Free fall and air resistanceA package is dropped from rest from a very tall tower and then, after some time, a parachuteopens to slow the package down.Initially the parachute is closed and the whole package is approximately a sphere of radius 50 cm and mass 40 kg.As the package falls through the air, the drag force increases as the velocity increases and,eventually, the package achieves its terminal velocity.The drag force (D) acting on the package is given by the equation:Drag force = constant (k) x cross sectional area (A) x velocity (v) squaredD = k A v2where: k = 0.7 Ns2/m4A is the cross sectional area of the sphere(i.e. the area of a circle of the same radius)v is the velocity(a) Show that the terminal velocity of the package before the parachute opens is approximately27 m/s.................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (3)(b) Without further calculation, state and explain how the terminal velocity would be affected if the40 kg package had a higher density than the package considered in (a).................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (2)The package considered in part (a) is travelling at its terminal velocity when theparachute is opened.Assume the stated drag formula also applies to the parachute when it is open.(c) Estimate the area of the parachute needed to reduce the terminal velocity of thepackage to 10 m/s.................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (2)(d) Calculate the resultant force acting on the package and parachute immediately after theparachute opens (assume the parachute opens instantly so that the parachute is initially movingat 27 m/s).................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (3)(e) In the space below draw an acceleration-time graph for the package from the moment it isreleased from rest until after the parachute opens and it achieves a final terminal velocity of10 m/s.Include a scale on the acceleration axis to show all significant values.It is not necessary to indicate a scale on the time axis.[4]14. Sound from a moving carA group of students investigates how the sound from a moving car appears to change itsfrequency (pitch) compared to when the car is stationary.They use a model where water drops from a source moving at a constant speed cause ripples to spread out on the surface of a tank of still water.In the model the ripples that spread out represent the sound waves from the moving car.The diagram shows the position where three drops landed and the position of the ripples due to the first two drops. The third drop has only just landed and so the ripple has not spread out yet.The ripples travel at speed v = 9.0 cm/sThe source moves at speed c = 4.0 cm/sThe drops occur every half second(a) State the frequency at which the drops are released................................................................................................................................................................................... (1)(b) Show that the time interval between successive ripples arriving at point X is 0.28 s. .................................................................................................................................................................................. ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (3)(c) State the frequency of the waves arriving at point X................................................................................................................................................................................... (1)When a car is stationary the horn has a frequency of 300 Hz.When the car moves at 5.00 m/s towards an observer the horn appears to have a slightly higher frequency.(d) By calculating the time period of the sound and referring to the model described previously,estimate the frequency of the horn that the observer hears.(speed of sound = 340 m/s).................................................................................................................................................................................. ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... .................................................................................................................................................................................. .................................................................................................................................................................................. ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (4)15. Distance to the SunThe distance from Earth to the Sun can be accurately calculated by measuring the distance fromEarth to Venus when exactly half of Venus is visible as seen from Earth.The angle between Venus and the Sun as seen from Earth is then measured.(a) Draw a labelled diagram to show the relative positions of Earth, Venus and the Sun when exactlyhalf of Venus is visible from Earth.[2](b) State the angle between a line drawn from the Sun to Venus and a second line drawnfrom Earth to Venus. (i.e. the angle between Earth and the Sun as seen from Venus) (1)(c) The distance to Venus is measured by accurately timing how long it takes a radar beam tobounce off Venus and return to Earth.Given that the speed of the radar beam is 2.9979 x108 m/s and the 'echo' of the radar signal isdetected 692.43 s after being transmitted, show that the distance to Venus is103.79 x106 km.................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (1)(d) Suggest a reason why the distance to the Sun cannot be measured using radar.................................................................................................................................................................................... (1)Astronomical angles are measured in fractions of a degree called minutes and seconds.1 degree = 60 minutes of angle1 minute = 60 seconds of angleThe angle between the Sun and Venus is measured to be:46 degrees 12 minutes 49 seconds (46o 12' 49'')(e) Express the angle in decimal form................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (2)(f) Calculate the distance from Earth to the Sun in km................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... ................................................................................................................................................................................... (2)[End of Questions]。
BPhO英国物理奥林匹克竞赛-AS- 2012-QuestionPaper问卷
A. 1 unit
B. 2 units
C. 3 units
D. 4 units
8. A heavy piece of apparatus used to measure sea salinity is attached by a short rope to a flexible rubber balloon filled with air. The balloon should sit on the surface of the sea. On one occasion too little air is put in and the balloon sits just below the surface of the sea. The sea becomes rough and the balloon sinks down just a little further. What is likely to happen to the apparatus?
Section A: Multiple Choice
Circle the correct answer to each question. There is only one correct answer. Each question is worth 1 mark. Write your answers in the table at the end of the multiple choice questions on page 3.
the mass of the smaller sphere, and the bar itself has a mass equal to the mass of the
smaller sphere.
bpho英国物理奥林匹克竞赛介绍
bpho英国物理奥林匹克竞赛介绍
BPhO（British Physics Olympiad，英国物理奥林匹克竞赛）是英国面向中学生开展的国家级物理竞赛，旨在发现和培养有物理天赋和兴趣的学生，促进物理学科的发展和普及。
BPhO竞赛分为多个不同级别的组别，包括：
1. 预备组：针对13岁以下学生，测试他们对物理基础概念的理解和应用能力。
2. 初中组：针对14-16岁的初中生，测试他们在基础物理知识和简单物理问题的解决能力。
3. 高中组：针对16-19岁的高中生，测试他们在更深入的物理概念和问题的解决能力。
除此之外，BPhO还举办在全国范围内的集训和选拔活动，选出最优秀的学生代表英国参加国际物理奥林匹克竞赛（IPhO）等国际物理竞赛。
通过参加BPhO竞赛，学生可以提高物理学科知识和解决问题的能力，增强自信心和竞争意识，获得更多的学术和职业发展机会。
大学生物理竞赛b类试题及答案
大学生物理竞赛b类试题及答案一、选择题（每题3分，共30分）1. 光在真空中的传播速度是多少？A. 2.99×10^8 m/sB. 3.00×10^8 m/sC. 3.01×10^8 m/sD. 3.02×10^8 m/s答案：B2. 根据牛顿第二定律，物体的加速度与作用力和物体质量的关系是？A. 加速度与作用力成正比，与质量成反比B. 加速度与作用力成反比，与质量成正比C. 加速度与作用力成正比，与质量成正比D. 加速度与作用力成反比，与质量成反比答案：A3. 以下哪种物质的比热容最大？A. 水B. 铁C. 铜D. 铝答案：A4. 电磁波谱中，波长最长的是？A. 无线电波B. 微波C. 红外线D. 可见光答案：A5. 根据能量守恒定律，以下哪种情况是可能的？A. 一个封闭系统内，能量可以被创造B. 一个封闭系统内，能量可以被消灭C. 一个封闭系统内，能量可以从一个物体转移到另一个物体D. 一个封闭系统内，能量可以从一个物体转移到另一个物体，但其总量保持不变答案：D6. 以下哪种力是保守力？A. 摩擦力B. 重力C. 弹力D. 空气阻力答案：B7. 根据热力学第一定律，系统内能的变化等于系统吸收的热量与对外做功的差值，用公式表示为？A. ΔU = Q - WB. ΔU = Q + WC. ΔU = W - QD. ΔU = W + Q答案：A8. 以下哪种物质的导电性最好？A. 橡胶B. 玻璃C. 铜D. 石墨答案：C9. 根据麦克斯韦方程组，变化的磁场可以产生？A. 恒定电场B. 变化的电场C. 恒定磁场D. 变化的磁场答案：B10. 以下哪种现象不是由量子力学效应引起的？A. 光电效应B. 电子的波动性C. 超导现象D. 布朗运动答案：D二、填空题（每题4分，共20分）1. 根据库仑定律，两个点电荷之间的静电力与它们的电荷量乘积成正比，与它们之间距离的平方成反比。
BPhO英国物理奥林匹克竞赛-Round 1第一轮-Paper2论文2-2010-Section2章节2
(iii) If the man is to climb to the top of the ladder, what is the minimum value of the coefficient of friction, μ, required on the ground? [10]
Q4
A weight of mass M hangs from the end of a light vertical spring that is attached, at its upper
(iii) Determine the resistance across AB.
[7]
(c)
C
R
Figure 5.c
The circuit in Figure 5.c has a capacitor C, with capacitance 50 μF, a diode and a resistor R, resistance R. It is used to rectify an a.c. supply of frequency 50 Hz and peak to peak voltage of 20 V. R can have the values of 10 kΩ or 100 Ω . In each case:
(c) Figure 2.c shows the cross-section of a glass prism, refractive index n, with the angles indicated showing a light ray passing through it. OS is perpendicular to EF.
AAPT物理竞赛和ARML数学竞赛
AAPT“物理杯”高中物理竞赛高中物理竞赛“物理杯”(PHYSICS BOWL)由“美国物理教师协会”(英文全称：American Association of Physics Teachers.缩写：AAPT）主办，是美国乃至全球最具影响力的高中生物理竞赛，每年有超过一万名美国优秀高中生参加。
在“物理杯”中取得最优异成绩的美国学生，将有机会受邀参加美国国家物理奥林匹克夏令营、甚至进入美国物理竞赛国家队。
在比赛中获得高分者备受美国名校欢迎。
过去8年中，仅1名高中生在该竞赛中得到满分。
美国物理教师协会是美国唯一专注于普及与提升物理教育的学术机构，由8000名美国大学物理教授、中学资深物理老师和物理教育工作者组成。
其中一半成员是美国各名牌大学物理教授，约1/3成员是美国高中的有经验的物理老师。
协会每年都会通过会议、论坛、杂志、竞赛等方式为美国大学与高中物理教育提供最新的物理前沿思想与更丰富的物理教育资源。
“物理杯”全部试题均由AAPT协会注册的大学物理教授和教学经验丰富的高中物理老师组成理事会进行出题和审核。
从2014年9月起，“物理杯”由AAPT协会和英国素质发展认证中心（ASDAN）合作，首度引入大中华地区。
这次在大中华区（大陆及港澳台）设立了五个赛区，比赛高分者将备受美国名牌大学的欢迎及更多竞争优势。
1. 参赛费用每人250元人民币（含考试费用、国际邮寄费与历年考试真题资料费用）2. 报名时间2016年3月20日截止3. 考位分配每个考点的考位有限，报完截止。
本赛区学校同学可以选择不同考点的考位，但是不能够跨赛区选择考位4. 选择考题不需预先分组，所有参赛选手下发同样试卷。
在答题卡上选择A组同学，回答1至40题，AAPT自动对1至40题评分；如果选择B组同学，回答10至50题，AAPT自动对10至50题评分。
5. 考试语言英文6. 考试时间2016年4月09日（星期六）下午：14:00-14:45 （45分钟）7. 考试地点全国主要城市各考点（报名注册后可以查阅、选择和注册参赛考点）8. 参赛人员高中各个年级学生9. 比赛内容笔试，40道单选题10. 考题难度说明考题分为两套，高一学生（IB10年级，A-Level的G1年级部分优秀学生和G2年级）建议选择Division1考题，高二，高三学生（IB11-12年级，A-Level年级）选择Division2考题。
高质量高中生物理竞赛汇总
高质量高中生物理竞赛汇总大家好，今天习美君为大家整理了高质量高中生国际物理竞赛汇总另外文末还有比赛讲座福利，不要错过。
事不宜迟，我们直接进入干货板块。
物理杯 Physics Bowl竞赛简介：Physics Bowl竞赛是全美极具影响力的高中物理思维挑战活动，由权威的美国物理教师协会（The American Association of Physics Teachers ，简称AAPT）主办。
AAPT成立于1930年，该协会旗下有8000名注册物理老师，其中一半成员是美国各名牌大学物理教授，约三分之一成员是美国高中的有经验的物理老师。
协会每年都会通过会议、论坛、杂志、活动等方式为美国大学与高中物理教育提供新鲜的物理前沿思想与更丰富的物理教育资源。
考题由协会注册的大学物理教授和具有丰富教学经验的高中物理教师组成的理事会进行呈现和评价。
这个项目是美国非常有影响力的高中物理思维挑战活动。
每年全球11个国家500多所名校参与其中，数万名选手全球排名。
在这个项目中获得高分的人受到美国名校的欢迎，获胜者将被邀请参加世界顶级的科学活动和研究项目。
九年来，只有一个高中生在这个项目上得了满分。
语言：英文报名截止时间：2022年3月16日比赛时间：2022年3月26日（周六）下午14:00—14:45（45分钟）比赛方式：个人比赛，试卷笔试，没有实验考试资格：任意年级高中生难度：题目分为两套，高一学生（IB10年级，A-level的G1年级部分优秀学生和G2年级）建议选择Division1考题，高二、高三学生（IB11-12年级，A-level年级）建议选择Division2考题。
Division2难度大于Division1地点：内容：40道单选题，持续45分钟奖项设置：（Division1和Division2分开排名）个人奖：•全球个人奖-全球排名前 100 名•全国获胜个人奖-全国前10名•区域获胜个人奖-区域前10名•全国金奖-全国排名前10%•全国银奖-全国排名前25%•全国铜奖-全国排名前35%•物理优秀奖-各区排名（除全国奖项外）前20%团队奖：（每个学校无论人数多少，取本校个人成绩前 5 名加总为团体总分；若不足 5 人，则所有选手得分加总为团体分）•全球获胜团队奖-全球排名前 50 位•全国获胜团队奖-全国前 10 名•区域获胜团队奖-区域前 10 名官网链接：中国区官网：普林斯顿大学物理竞赛 Princeton University Physics Competition竞赛简介：普林斯顿大学物理竞赛是一项面向国际高中生的物理竞赛，由普林斯顿大学物理系和天体物理系组织。
BPhO英国物理奥林匹克竞赛-Round 1第一轮-part1部分1-20142015-Paper论文-final决赛
BRITISH PHYSICS OLYMPIAD 2014-15BPhO Round 1Section 114th November 2014InstructionsTime: 1 hour 20 minutes.Questions: Students may attempt any parts of Section 1. Students are not expected to complete all parts.Marks: A maximum of 40 marks can be awarded for Section 1. There are a total of 67 marks allocated to the problems of Question 1 which makes up the whole of Section 1.Solutions: Answers and calculations are to be written on loose paper or examination booklets. Graph paper and formula sheets should also be made available. Students should ensure their name and school is clearly written on all answer sheets.Setting the paper: There are two options for setting BPhO Round 1:•Section 1 and Section 2 may be sat in one session of 2 hours 40 minutes.•Section 1 and Section 2 may be sat in two sessions on separate occasions; with1 hour 20 minutes allocated for each section. If the paper is taken in two sessions onseparate occasions, Section 1 must be collected in after the first session andSection 2 handed out at the beginning of the second session.Important ConstantsSpeed of light c 3.00 x 108ms-1 Planck constant h 6.63 x 10-34Js Electronic charge e 1.60 x 10-19 C Mass of electron m e9.11 x 10-31kg Gravitational constant G 6.67 x 10-11Nm2kg-2 Acceleration of free fall g9.81 ms-2Q1.(a)The circuit in Figure 1.(a) contains a cell of emf E , a known variable resistance R0 ,an unknown resistance R and an ammeter. When X and Y are short circuited E = I0R0When R is inserted the current is αI0 , where α is a constant.Figure 1.(a)(i)Express R in terms of R0 and α, giving the range of validity of R and α.(ii)In order to extend the range of α, modify the circuit by putting R in parallel with R0. Determine the ranges of R and α for the modified circuit.[4](b) A man, on an open wagon of a train travelling along a straight horizontal track at aconstant speed of 10 ms-1 , throws a ball into the air in line with the track, that hejudges to be at 60o to the horizontal. A woman standing on the ground observes the ball rise vertically.How high does the ball rise relative to(i)the man and;(ii)the woman?[5](c)A glass block of refractive index μ = 1.5 has an ‘L’ cross-section, Figure 1.(c), and is ofconstant width and thickness.Figure 1.(c)(i) A laser beam enters the block from the left, as indicated in Figure 1.(c), at anincident angle of θ = 45o. If the block was absent the beam would passthrough the point P. Determine the angle at which the beam will emergefrom the bottom face after refraction through the block.(ii) If this beam enters the block below the horizontal through P, determine itspossible subsequent path(s).[6](d)The largest moon of Jupiter, Ganymede, revolves around the planet in a circular orbitof radius 1.07 x 106 km and period 7.16 days. Determine the mass of Jupiter, M J, in terms of the mass of the Earth, M E.The radius of the Earth R E = 6.38 x 106 m[5](e)Two 1.00 m lengths of wire, one copper and one tungsten, are joined vertically endto end. The copper wire has a diameter of 0.500 mm. When a 100 kg block issuspended from one end, the combined length of wire stretches by 6.00 cm. What is the diameter, d, of the tungsten wire if the Young’s modulus for copper is 12.4 x 1010 Pa, and that for tungsten is 35.5 x 1010 Pa?[6](f)Wood from the coffin of an Egyptian mummy showed a specific activity of 1.2 x 102parable living wood has a value of 2.0 x 102 s-1kg-1. The half life ofcarbon-14 is 5.70 x 103 years. What is the time interval, T B , in years, since the burial?[5](g)Explain why the centre of gravity of a triangular plate lies along a median; the linejoining a vertex to the midpoint of the opposite side. An equilateral triangular plate, sides of length b, has a triangle, formed by two corners and the centre of gravity of the original plate, removed. Determine the centre of gravity of the remaining plate.The centre of gravity of a triangular plate is at a point two thirds along the length ofa median measured from the vertex.[7](h)A vertical U-tube, partially filled with liquid, is accelerated vertically upwards in a lift,acceleration α. What is the effective value of 'g', g v? If the U-tube is mounted in a vehicle accelerating in a horizontal straight line, acceleration a, Figure 1.(h), what is the effective 'g', g h ? Express a in terms of the distance between the arms of the U-tube, L ,and the difference in heights, h, of the liquid in the arms.[7]Figure 1.(h)(i)In Figure 1.(i) a fixed mirror, a light source and a light receiver are all 0.30 km from arotating mirror, with angular frequency ω. The distance between the light source and the receiver is 0.60 m. What is the lowest value of ω required for detection of the reflected light?[4]Figure 1.(i)(j) A car travelling at 90 km/hr in a straight line sounds its horn continuously, frequency 400 Hz, as it passes a stationary observer. At the closest point, A, to the observer the car is at a distance D = 100 m from the observer. Determine the frequency heard by the observer when the car is:(i)at A;(ii)at a distance x from A, after passing AThe velocity of sound is v S = 343 ms-1.[8](k)A ball of mass m and velocity u collides elastically with a larger ball of mass M, initially at rest. The ball of mass m rebounds along its original line of motion with speed v1 and the ball of mass M has velocity v2 in the direction of u.(i)Write down the conservation equations for the system.(ii)Deduce the result that u – v1 = v2.[5](l) A velocity selector, Figure 1.(l) , consists of two slotted discs mounted on a common axis a distance d apart. The slots are displaced relative to each other by an angle θ .The axis is driven at an angular velocity ω . Particles in a horizontal beam, with all possible velocities, will get through the first slit, in the first disc, for a short timeinterval. To subsequently get through the second slit, particles must travel a distanced in the times it takes the second slot to line up with the beam. This will occur, forrotations of the second slit of θ, 2π+θ, 4π+θ ,.. etc.If d =1.00 m, ω = 24,000 rpm and θ = 60o, what are the speeds of those particles that pass through the velocity selector?[5]Figure 1.(l)End of Questions。
BPhO英国物理奥林匹克竞赛-A2 ChallengeA2挑战-2012-Question Paper问卷
BRITISH PHYSICS OLYMPIADBritish Physics Olympiad 2012 A2 Challenge (previously Paper 1)September /October 2011Answer all questions Allow 1 hour Total 50 marksg = 9.8 m s‐2 or N kg‐1 c = 3.0 x 108 m s‐1 A standard formula sheets should be made available for students1Question 1When a satellite is launched to a distant planet, a radioisotope thermoelectric generator (RTG) is used to provide electrical power for the satellite. This consists of a decaying radioactive source producing heat which can then be converted to electrical power. NASA is allowed to launch with a maximum 25 kg mass of plutonium dioxide (PuO2) on a single satellite, but it never uses the maximum. a) Pu-238 itself alpha decays and NASA quotes the specific activity of the radioactive PuO2 as 17 Cu/g, where 1 curie (Cu) is 3.7 x 1010 decays per second. Calculate the number of alphas released per second from 1 g of PuO2. b) If the plutonium emits 5.5 MeV alphas, how many watts of power per gram are released by the radioactive source? This quantity is known as the power density. c) At launch, 4.5 kW of heat power are required from the source. What mass of radioactive PuO2 is required? d) If the conversion efficiency from thermal to electrical energy is 7%, what electrical power will this supply initially? e) Why are solar panels not used for satellites travelling to distant planets? 1 eV = 1.6 x 10-19 J(6 marks)Question 2The value of the acceleration due to gravity, g decreases as1 where r is the radial r2distance measured from the centre of the Earth (this follows from Newton's Law of Gravitation). a) By what percentage is g less than the value of 9.81 m s-2 measured at the surface of the Earth, when measured at the height of a satellite orbit of 300 km above the Earth's surface? b) What would be the value of g at the distance of the Moon (the Moon is 400,000 km away from the Earth)? Radius of Earth = 6,400 km(5 marks)2Question 3The physicist is inevitably well prepared for travelling and packs his clothes into the idealised rolling suitcase. The empty, rectangular suitcase has a uniform mass distribution of 5 kg acting as a load at the centre of mass. In this question, the load is measured in kilograms rather than being converted into newtons. The case has a pair of wheels at corner C and a handle at corner A, as shown in the diagram below. The suitcase contents can be modelled as two point masses of 14 kg and 4 kg, of clothing and shoes respectively, located at diagonally opposite corners of the suitcase. When the handle end of the case is just raised off the ground, so that CD is horizontal, the physicist is not lifting the full 23 kg of load. a) State or sketch on a rectangle where the load of the empty suitcase acts. b) Fill in the right hand column of the table with the values for the load (measured in kilograms, kg) that the physicist would feel with the distributions of the masses at diagonally opposite corners. (You only need to copy down the first and final two columns of the table). c) If instead the two masses could now be placed at any two corners of the case, which examples would be the two best choices and what would be the load when lifting the handle at A? d) Of these two examples in (c), suggest which arrangement might be better if pulling the suitcase over rough ground and explain your answer.Example 1 2 3 4A 14 kg 4 kgBC 4 kg 14 kgDWorking outLoad at handle14 kg 4 kg A4 kg 14 kg BDC(8 marks)Figure 1. The physicist’s ideal suitcase on wheels.3Question 4The Physical Review is a distinguished physics journal that has been published continuously since 1893. We will assume that a volume is published twice a year. After about 1935 there was a sharp increase in the number of articles that were published in each volume making it thicker and thicker such that, when it was stacked on the library shelf every six months, the front cover of the journal could be said to be moving along with an ever increasing velocity. A physicist at the time pointed out that if this continued then the front cover of the journal would eventually exceed the speed of light (but then according to relativity theory there would be no information transmitted). We assume a simple model: • that the number of articles per volume increase exponentially, doubling every six months (the articles are of similar length) • at the beginning of 1935 the volume was 1 cm thick • that the velocity of the front cover is the thickness of that volume divided by the number of seconds in six months.Figure 2. Volumes of the Physical Review doubling in thickness every six months. You must show your working in the following questions. a) By what factor does the thickness of the volume increase each year? b) What would be the thickness of the volume put on the shelf at the beginning of 1940? c) Write down your answer to (b) to one significant figure and in standard form. d) Using your answer to part (c), write down the thickness of each volume for the next three years. e) Determine the year when the front cover of the volume stacked will exceed the velocity of light. You may find it helpful to write your answer to part (d) including a term of the form 4n. Hint: use logs to base 10 log10 xn = n log10 x(10 marks)4Question 5There are several factors which determine the maximum height of a mountain. Everest at only 8 km is not very high in terms of the maximum height that can be attained given the strength of the rock. All mountains on Earth suffer from erosion which reduces their height significantly. The maximum height is limited by the rock flowing under the enormous weight above it, which is related to the Young's Modulus value for the rock, E. We can suggest that an equation for the maximum height of a mountain would depend upon the density of the rock, ρ, Young’s Modulus, E, and the strength of Earth’s gravity, g. An insight into the solution of a problem can often be made by looking at the dimensions of the relevant physical quantities. a) E is a measure of how much the rock deforms when a load is applied to it. E has units of N m-2. Write down the units of E, ρ and g in terms of meters, kilograms and seconds (m, kg, s). b) If the height of the mountain is given by the formula h = constant x E x ρα x gβ , by comparing the units on the left and right hand sides of the equation (the constant has no units), determine the values of α and β and write down the equation for h. c) If the value of E for rock is 1010 Pa, the density of rock is 3 x 103 kg m-3 and the value of the constant is 1, estimate to one significant figure the height of a mountain that will be given by the formula. (Such a mountain is to be found on Mars).(9 marks)Question 6When liquid nitrogen at a temperature of 77 kelvin or -196 oC is poured into a beaker, it is observed to boil continuously as heat enters it from the surroundings. When stored in a full 25 litre Dewar flask (an insulated steel container similar to a thermos flask), it takes 100 days for all of the liquid nitrogen to boil away. The rate at which heat enters (i.e. power entering) the Dewar flask is very low and we can estimate the value using the results of the following experiment.Figure 3. Liquid nitrogen DewarFigure 4. Electrical heater suspended in liquid nitrogen5A beaker of liquid nitrogen is placed on an electronic balance and readings of the mass are taken every twenty seconds. A small electrical heater is suspended in the liquid, and the experiment is carried out twice, once with the heater turned off and then repeated with the heater connected to the electrical supply. A graph is plotted of the two sets of results and the lines of best fit are obtained, along with the equations. The graph is shown below. a) Calculate the rate of loss of liquid nitrogen in grams per second, for each of the two cases, using the data from the graph. The equations for the lines of best fit are given. b) The heater supply is V=3.9 volts, I=1.2 amps. Calculate the number of joules per second supplied by the heater. c) Calculate the energy from the heater required to boil away one gram of liquid nitrogen. d) Calculate the heat power from the room entering the beaker of nitrogen. e) Calculate the average power that must enter the full 25 litre Dewar to boil away the nitrogen in 100 days. Density of liquid nitrogen is 810 kg m-3 (1 m3 = 1000 litres).(12 marks)[End of Questions]6。
物理竞赛的英语作文带翻译
Participating in physics competitions can be highly beneficial for students. Firstly, it offers them an opportunity to apply the knowledge they have gained in the classroom to real-world situations. This practical application of science not only reinforces their understanding of the subject but also fosters a deeper interest in the discipline. Additionally, competitions provide students with a chance to collaborate with their peers, enhancing their teamwork and communication skills.They also learn to think creatively and critically, as they tackle complex problems under time constraints. These experiences are invaluable for students’ personal and academic growth.
物理提问回答大竞赛的活动方案
物理提问回答大竞赛的活动方案English Answer:Introduction.The Physics Q&A Grand Challenge is an exciting competition designed to inspire and engage students in the field of physics. This event will provide a platform for students to demonstrate their knowledge, problem-solving skills, and critical thinking abilities while fostering a spirit of competition and camaraderie.Eligibility and Participation.The competition is open to all high school students currently enrolled in physics classes. Teams consisting of 2-4 students are encouraged to participate. Each school is limited to sending a maximum of two teams. Interested teams should register online by [insert deadline].Format and Rules.The competition will consist of three rounds:Round 1: Written Test.Teams will complete a written test covering a range of physics topics. The test will be 90 minutes in duration.Round 2: Oral Presentation.The top teams from Round 1 will advance to Round 2, where they will present their solutions to a specific physics problem to a panel of judges. Teams will have 15 minutes to present their findings, followed by a 5-minute question-and-answer session.Round 3: Physics Challenge.The top teams from Round 2 will compete in a live physics challenge. The challenge will involve solving a complex physics problem under time constraints. Teams willbe given materials and equipment to assist in their solution.Winners will be determined based on their performancein each round, with the team scoring the highest cumulative total being declared the champion.Prizes and Recognition.The winning team will receive a trophy and a cash prize. All participating teams will receive certificates of participation. Additionally, outstanding individual performances will be recognized with special awards.Benefits of Participation.Participation in the Physics Q&A Grand Challenge offers numerous benefits for students, including:Enhanced understanding of physics concepts.Development of problem-solving and critical thinkingskills.Improvement in teamwork and communication abilities.Opportunity to compete against peers from other schools.Recognition for academic excellence.Call to Action.We invite all interested teams to register for the Physics Q&A Grand Challenge. This is an exceptional opportunity for students to showcase their knowledge and passion for physics. The competition promises to be an enriching and rewarding experience for all participants. Deadline to register is [insert deadline].中文回答：简介。
bpho难度与全国高中物理竞赛
bpho难度与全国高中物理竞赛英国物理竞赛BPhO不同于美国物理碗（Physicsbowl）全都是选择题，BPhO几乎都是解答题，对选手来说难度比较高，那含金量自然也比较高。
难度说高也是相对的，对于学生来说，只要掌握了高中物理的大部分知识，还是可以去参加考试的。
今天小编就要向大家介绍一下英国物理竞赛BphO的难度分析。
英国物理奥赛简介：BritishPhysicsOlympiad（BphO）英国物理奥赛始于19XX年，至今已近25年的历史，每年英国本土超1，600位有天赋的青年物理学家参赛。
19XX年起，BphO正式为英国选拔国家代表队，主要由牛津大学、英国物理学会和Odgen基金会组成，办公室设在牛津大学物理系。
BphO非常注重物理知识的灵活运用，全部的试题为证明题。
参赛者需运用自己所学物理知识完成挑战，其涉及的知识点非常广泛，考试不要求同学们完成所有试题，而是鼓励同学们根据自己兴趣和学习范围选择完成自己擅长的部分。
英国国籍的优秀选手将代表英国组成国家队参加国际物理奥赛。
英国物理竞赛难度，对于G1年级的学生来说，去参加BPhO竞赛是比较困难的，一个原因是因为题目的难度比较大，另外一原因是因为很多知识点没有学过。
考场上如果知识点都还没有触及，很难会获得成绩。
虽然BPhO对年级没有要求，但是G1年级的学生的物理水平基本都是初二或者初三水平，而英国物理竞赛对知识点掌握的基本要求是学完大部分的高中物理知识，所以要求学生至少要学完IGCSE的物理内容，最好有一些AlevelPhysics的基础。
对于G2年级的学生来说，物理水平高，愿意主动思考的学生可以考虑参赛。
虽然第一年可能不会有好的成绩，但是第一年可以当做是练手和获得比赛经验，等到A1时真正拿到比较好的成绩，对申请和出国来说都非常有利。
英国物理奥赛考试题型，该比赛一共分为两套题Section1和Section2.Section1一共有约15道题，每道题根据难度不同有不同的分值（3-10分不等），总分值约在94分。
全国物理竞赛流程英文版
全国物理竞赛流程英文版The National Physics Competition is an annual event that attracts talented young physicists from all across the country. The competition aims to foster interest in physics and identify the most promising young minds in the field. The competition consists of several rounds, each designed to test the participants' knowledge, problem-solving skills, and creativity.The first round is a written exam that covers a wide range of topics in physics, including mechanics, thermodynamics, electromagnetism, and quantum mechanics. The questions are designed to be challenging and thought-provoking, requiring the participants to demonstrate a deep understanding of the fundamental principles of physics.The top scorers from the written exam move on to the second round, which consists of a series of practicalexperiments. In this round, the participants are given a set of materials and equipment and are asked to perform various experiments and analyze the results. This round is designed to test the participants' ability to apply their theoretical knowledge to real-world situations and to think critically and analytically.The third round is a series of oral examinations in which the participants are asked to present and defend their own research projects. This round allows the participants to showcase their creativity, originality, and ability to communicate their ideas effectively.Finally, the top performers from the previous rounds are invited to the national finals, where they compete in a series of head-to-head challenges, including problem-solving, design challenges, and live demonstrations. The national finals are a thrilling culmination of the competition, wherethe participants have the opportunity to demonstrate their skills and compete for the title of National Physics Champion.Overall, the National Physics Competition is a rigorous and demanding yet rewarding experience that allows young physicists to showcase their talents, learn from each other, and ultimately inspire the next generation of scientists.。
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Name: Total MarkSchool:Physics Challenge 2012-13Time allowed: 1 hourAttempt all questionsWrite your answers on this question paperYou may use a calculatorAssume the gravitational field strength has a value of 10 N / kgSection A:Ten multiple choice questions worth 1 mark each (worth 10 marks in total) Allow about 15 minutes for this sectionSection B:Two short answer questions (worth 8 marks in total)Questions require a clear explanation of the underlying physical principlesAllow about 10 minutes for this sectionSection C:Longer answer questions requiring calculations (worth 32 marks in total) Questions may be set on unfamiliar topics. Additional informationnecessary to answer the question will be given in the questionAllow 35 minutes for this sectionTotal 50 marks; mark allocations for each sub-section are shown in bracketsSection A: Multiple Choice AnswersWrite the correct letter in the grid. The first column has been done as an example if the answer to question zero were CQuestion 0 1 2 3 4 5 6 7 8 9 10 Answer CSection A: Multiple Choice Questions1. Which of the following is NOT a unit of energy?A. CalorieB. Joule per secondC. Kilowatt hourD. Kilogram meter squared per second squaredE. Newton meter2. The masses and dimensions of four samples of metal were measured.The results are shown below:Sample Dimensions (cm) Mass (g)i 2.0 x 2.0 x 2.0 40ii 2.0 x 2.0 x 4.0 160iii 2.0 x 4.0 x 4.0 160iv 4.0 x 4.0 x 4.0 80The two samples that could be the same material are:A. i and iiB. i and iiiC. i and ivD. ii and iiiE. ii and iv3. In an experiment to investigate static electricity, two objects were found to attract each other.One possible explanation for this is:A. Both objects were positively chargedB. Both objects were negatively chargedC. Both objects were unchargedD. One object was positively charged and the other was unchargedE. One object was plastic and the other was metal4. The graph shows how the activity of a radioactive sample changes over time.The half-life of the sample is approximately:A. 5 minutesB. 7.5 minutesC. 9 minutesD. 15 minutesE. 40 minutes5. In Rutherford’s famous alpha particle scattering experiment, small positively charged sub-atomic particles called alpha particles were fired at a very thin sheet of gold foil. Most of the alpha particles passed straight through the gold foil as expected but, much to Rutherford’ssurprise, some of the alpha particles bounced off the gold foil at large angles.The results of this experiment suggest that:A. Atoms have a small dense nucleusB. Atoms contain charged particlesC. Atoms have orbiting electronsD. Atoms are small hard spherical objectsE. Gold can be used to make effective mirrors6. The circuit shows a filament lamp connected to a variablepower supply.The lamp can work at any voltage up to 18 V withoutdamage.When the bulb is operated at a voltage of 6 V it dissipates a power of 12 WWhen the voltage is increased to 12 V, the power dissipated will be:A. 12 WB. Between 12 W and 24 WC. 24 WD. Between 24 W and 48 WE. 48 W7. A 2.0 kW electric heater is used for 3 hours.The total energy dissipated by the heater during this time period is:A. 6 joulesB. 360 joulesC. 6,000 joulesD. 360,000 joulesE. 22,000,000 joules8. A swimmer dives into a completely calm 25 m long swimming pool.The ripple from the dive travels across the surface of the pool at 2.5 m/s, reflects o ff the far end and travels back down the pool to meet the swimmer.After diving in at the end, the swimmer swims at a steady speed that would take him 20seconds to swim the length of the pool.The swimmer and the returning ripple meet when the swimmer has travelled approximately:A. 10 mB. 12.5 mC. 17 mD. 20 mE. 25 m9. An archery bow is pulled back 80 cm with an average force of 300N. An arrow of mass 50gis released from the bow. Assuming 60% the work done in pulling back the bow istransferred to the arrow as kinetic energy, the speed of the arrow will be approximately:A. 2.4 m/sB. 76 m/sC. 98 m/sD. 170 m/sE. 5800 m/s10. The time period for one oscillation of a long swinging pendulum is to be determined. Thetime is to be measured using a hand held stopwatch with a p recision of 1/100th of a second.The time period is known to be about 2 seconds.Which of the following measurement techniques best reduces the uncertainty on themeasured value of the time period?A. Measuring the time for 10 swings and dividing the result by 10.B. Measuring the time for 1 swing 10 times and taking an average.C. Using a stopwatch that measures with a precision of 1/1000th of a second.D. Having 10 different people measure the time period and taking an average.E. Ensure room temperature remains the same throughout the experiment.11. Explain what effect doubling the speed of a vehicle will have on the total stoppingdistance if all other factors such as driver alertness, braking performance and roadsurface stay the same.[4 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................12. Explain, in terms of pressure, how it is possible to use a drinking straw to drink from a glass of water.[4 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................…............................................................................................................................................................13. A question about opening a jam jarWhen jam is made, it is put into the jam jar and the top screwed down whilst the jam is still hot. The top makes an airtight seal with the jar and the air trapped above the jam cools and so the pressure of the trapped air reduces.Useful information:For the airp / T = constantassuming no air escapes/enters and the volumeof the trapped air remains constantp = pressure of the trapped airT = Temperature in KelvinAtmospheric pressure = 100 kPa(at room temperature)Absolute zero = -273 ºCa) Calculate the force, due to atmospheric pressure, acting downwards on the top of the circularlid of the jam jar[3 marks] …............................................................................................................................................................ …...........................................................................................................................................................b) The jam and the trapped air were initially at a temperature of 85 °C when the jam was putinto the jar and lid secured.Show that the pressure of the trapped air, once it has cooled to a room temperature of 15 °C inside the jar is approximately 80 kPa[3 marks] …............................................................................................................................................................ …............................................................................................................................................................…............................................................................................................................................................c) Calculate the resultant force acting on the lid of the jam jar[2 mark] …............................................................................................................................................................ …............................................................................................................................................................d) Explain why running the jam jar under the hot tap can make it easier to remove the top[2 mark] …............................................................................................................................................................ …............................................................................................................................................................14. Analysis of a lightning strike (data analysis question)This question asks you to use unfamiliar equations and concepts to solve a problem.You will not have met some of the concepts in your normal physics course.All of the information you need to solve the problem is given in the question.A student was interested to workout if the copper cable connecting alightning conductor to the groundwould melt if it was struck bylightning.They considered a simple modelwhere a fixed current flowedthrough the conductor for a certaintimeThey found the followinginformation about lightning strikes:Average current flowing throughconductor in a lightning strike =300 kAAverage time for a lightning striketo fully discharge from cloud = 2 x10-3 sThe students found the following useful data about the copper conductor:Equation to calculate the resistance of a cable is R = ρ L / A(R = resistance, L = length, A = cross-sectional area and ρ = constant called resistivity)Resistivity of copper, ρ = 1.7 x 10-8ΩmSpecific heat capacity of copper = 385 J kg-1 ˚C-1(Energy needed to raise 1kg by 1o C)Density of copper = 8900 kg/m3Melting point of copper = 1085 ˚Ca) Show that the resistance of the conductor is approximately 2 mΩ[3 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ For current flowing through a resistor we can use the equation, P = I2R where P = Power, I = Current and R = Resistanceb) Calculate the power dissipated in the conductor and hence show that the energy transferred to the conductor is approximately 400 kJ[3 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................c) Calculate the mass of the thick copper conductor[3 marks] …............................................................................................................................................................ …............................................................................................................................................................d) Hence calculate the temperature rise experienced by the conductor and show that the conductor is unlikely to melt[3 marks] …............................................................................................................................................................ …............................................................................................................................................................…............................................................................................................................................................15. Modelling the acceleration of a carA car accelerates from rest in a straight line.The driving force from the engine remains constant but the acceleration of the car reduces over the next four seconds due to several factors including increased drag.A graph of acceleration against time for the first four seconds is shown below:To analyse the motion of the car, the graph is divided into 1 second time intervals.Although the acceleration is constantly changing, the problem is simplified by assuming the acceleration in each 1 second time interval remains constant for the duration of that interval and is equal to the average acceleration for that time interval.This is a simplified model of the complex motion of the car.a) Use the graph to estimate the average acceleration for each time interval:[2 mark]t = 0.0s to t = 1.0s Average acceleration = …........................................... m/s2t = 1.0s to t = 2.0s Average acceleration = …........................................... m/s2t = 2.0s to t = 3.0s Average acceleration = …........................................... m/s2t = 3.0s to t = 4.0s Average acceleration = …........................................... m/s2b) Complete graph 2 (below) to show average acceleration against time assuming that theacceleration remains constant for the given time interval[2 marks]c) Complete graph 3 (below) to show the velocity against time for the car assuming theacceleration remains constant for the given time interval.Indicate significant numerical values on the y-axis[2 marks]d) Using the graph 3 or otherwise, calculate the distance travelled by the car in the first 4 seconds[2 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................An engineer suggests that the Drag force is directly proportional to the velocity of the car.e) Use numerical data from the problem to demonstrate that, in this example, the drag force isNOT proportional to the velocity[2 marks] …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................ …............................................................................................................................................................。