2016年广东工业大学考研真题847大学物理学
大学物理考试试题库经典版(含答案)
第一章 质点运动学基本要求:1、掌握位矢、位移、速度、加速度、角速度和角加速度等物理量。
2、能计算速度、加速度、角加速度、切向加速度和法向加速度等。
教学重点:位矢、运动方程,切向加速度和法向加速度。
教学难点:角加速度、切向加速度和法向加速度。
主要内容:本章首先从描述物体机械运动的方法问题入手,阐述描述运动的前提——质点理想模型、时间和空间的量度,参照系坐标系。
其次重点讨论描写质点和刚体运动所需要的几个基本物理量(如位移、速度、加速度、角速度、角加速度等)及其特性(如相对性、瞬时性、矢量性)。
(一)时间和空间研究机械运动,必然涉及时间、空间及其度量.我们用时间反映物体运动的先后顺序及间隔,即运动的持续性.现行的时间单位是1967年第13届国际计量大会规定的,用铯(133Cs )原子基态的两个超精细能级间跃迁相对应的辐射周期的9 192 631 770倍为1秒.空间反映物质的广延性.空间距离为长度,长度的现行单位是1983年10月第17届国际计量大会规定的,把光在真空中1/299 792 458秒内走过的路程定义为1米.(二)参照系和坐标系宇宙间任何物质都在运动,大到地球、太阳等天体,小到分子、原子及各种基本粒子,所以说,物质的运动是普遍的、绝对的,但对运动的描述却是相对的.比如,在匀速直线航行的舰船甲板上,有人放开手中的石子,他看到石子作自由落体运动,运动轨迹是一条直线,而站在岸边的人看石子作平抛运动,运动轨迹是一条抛物线.这是因为他们站在不同的物体上.因此,要描述一个物体的运动,必须先确定另一个物体作为标准,这个被选作标准的物体叫参照系或参考系.选择哪个物体作为参照系,主要取决于问题的性质和研究的方便.在研究地球运动时,多取太阳为参照系,当研究地球表面附近物体的运动时,一般以地球为参照系.我们大部分是研究地面上物体的运动,所以,如不特别指明,就以地球为参照系. (三)质点实际的物体都有一定的大小和形状,物体上各点在空中的运动一般是不一样的.在某些情况下,根据问题的性质,如果物体的形状和大小与所研究的问题关系甚微,以至可以忽略其大小和形状,这时就可以把整个物体看作一个没有大小和形状的几何点,但是它具有整个物体的质量,这种具有质量的几何点叫质点.必须指出质点是一种理想的物理模型.同样是地球,在研究它绕太阳公转时,把它看作质点,在研究它的自转时,又把它看作刚体. (四)速度0d limd t t t∆→∆==∆r r v速度v 是矢量,其方向沿t 时刻质点在轨迹上A 处的切线,它的单位是m ·s -1.(五)加速度220d d lim d d t t t t ∆→∆===∆v v ra加速度a 是速度v 对时间的一阶导数,或者是位矢r 对时间的二阶导数.它的单位是m ·s -2. (六)圆周运动圆周运动是最简单、最基本的曲线运动,2d ,d n vv a a tRτ==习题及解答: 一、填空题1. 一质点作半径为R 的匀速圆周运动,在此过程中质点的切向加速度的方向 改变 ,法向加速度的大小 不变 。
大学物理考试试卷答案精析详解
大学物理考试试卷 答案精析详解1.在边长为a 的正方体中心处放置一电荷为Q 的点电荷,则正方体顶角处的电场强度的大小为:(A) 2012a Q επ. (B) 206a Qεπ.(C)203a Q επ. (D)20aQεπ. [ c ] 解:求得点至正方体顶点距离平方为3/4a ,再用场强公式即可。
2.图示为一具有球对称性分布的静电场的E ~r 关系曲线.请指出该静电场是由下列哪种带电体产生的.(A) 半径为R 的均匀带电球面. (B) 半径为R 的均匀带电球体. (C) 半径为R 的、电荷体密度为ρ=A r (A 为常数)的非均匀带电球体. (D) 半径为R 的、电荷体密度为ρ=A/r (A 为常数)的非均匀带电球体.[b ]解:均匀带点球体,内部电场强度E=3r/eo ,场强大小随E 增大而增大 球体外部,电场强度为(4PI/eo ) * (q/r*r )故E 随r 平方增大而减小。
3.选无穷远处为电势零点,半径为R 的导体球带电后,其电势为U 0,则球外离球心距离为r 处的电场强度的大小为(A) 32r U R . (B) R U 0. (C)20r RU . (D) r U 0. [ c ]E解:解此题需要运用到高斯定理。
4.如图,在一带有电荷为Q 的导体球外,同心地包有一各向同性均匀电介质球壳,相对介电常量为εr ,壳外是真空.则在介质球壳中的P 点处(设r OP =)的场强和电位移的大小分别为(A) E = Q / (4πεr r 2),D = Q / (4πr 2).(B) E = Q / (4πεr r 2),D = Q / (4πε0r 2).(C) E = Q / (4πε0εr r 2),D = Q / (4πr 2).(D)E =Q /(4πε0εr r 2),D =Q / (4πε0r 2). [ c] 解:e=eo*er 此时的电场强度计算公式照常,电位移的概念为D=E/e5. 一个平行板电容器,充电后与电源断开,当用绝缘手柄将电容器两极板间距离拉大,则两极板间的电势差U 12、电场强度的大小E 、电场能量W 将发生如下变化: (A) U 12减小,E 减小,W 减小. (B) U 12增大,E 增大,W 增大.(C) U 12增大,E 不变,W 增大.(D) U 12减小,E 不变,W 不变. [ C ]解:电容器与电源断开,电板间的总电量Q 不变,C 减小,则U 增大,而E 不变,W=Q*Q/2C 增大 6.通有电流I 的无限长直导线有如图三种形状,则P ,Q ,O 各点磁感强度的大小B P ,B Q ,B O 间的关系为:(A) B P > B Q > B O . (B) B Q > B P > B O . (C) B Q > B O > B P . (D) B O > B Q > B P . ( d ) 解:[ ]7.(本题3分)(2047) 如图,两根直导线ab 和cd 沿半径方向被接到一个截面处处相等的铁环上,稳恒电流I 从a 端流入而从d 端流出,则磁感强度B 沿图中闭合路径L 的积分⎰⋅Ll Bd(A) I 0μ. (B)I 031μ. (C) 4/0I μ. (D) 3/20I μ.[D ]解:运用电场环流定理,⎰⋅Ll Bd = 3/20I μ。
广东工业大学考研历年真题
广东工业大学考研历年真题【第一部分:单项填空】1. However, some actors _____ us with the deep feelings they can inspire in us for a character they are playing. [单选题] *A.astonishedB. astonishingC. astonish(正确答案)D. is astonished2. He was a _____ figure in the French film industry. [单选题] *A. dominantlyB. dominant(正确答案)C. dominanceD. dominants3. The morning after your arrival, you meet with the _____ physician for a private consultation. [单选题] *A. residentsB. resident(正确答案)C. residenceD. residences4._____a reply, he decided to write again. [单选题] *A. Not receivingB. ReceivingC. Not having received(正确答案)D. Having not received5.With lots of trees and flowers _____here and there, the city looks very beautiful. [单选题] *A. having plantedB. planted(正确答案)C. have been plantedD. to be planted6. I have bought two ball-pens, _______ writes well. [单选题] *A. none of themB. neither of themC. neither of which(正确答案)D. none of which7.Great changes have taken place since then in the factory _______we are working. [单选题] *A.where(正确答案)B.hatC.whichD.there8.The engineer ______my father works is about 50 years old. [单选题] *A. to whomB. on whomC. with whichD. with whom(正确答案)9.The reason ______he didn't come was ______he was ill. [单选题] *A. why; that(正确答案)B.that;whyC. for that;thatD.for which;what10. Is _______ some German friends visited last week? [单选题] *A. this schoolB. this the schoolC. this school oneD. this school where(正确答案)11. They are not very good, but we like_______. [单选题] *A. anyway to play basketball with themB. to play basketball with them anyway(正确答案)C. to play with them basketball anywayD. with them to play basketball anyway12. He sent me an e-mail, _______to get further information. [单选题] *A. hopedB hoping(正确答案)C. to hopeD. hope13._____in 1636, Harvard is one of the most famous universities in the United States. [单选题] *A. Being roundedB it was foundedC. Founded(正确答案)D. Founding14.The ____boy was last seen ______near the East Lake. [单选题] *A. Missing, playing(正确答案)B. missing, playC missed, playedD missed, to play15. Tony was very unhappy for _______ to the party. [单选题] *A. having not been invitedB. not having invitedC. having not invitedD not having been invited(正确答案)【第二部分:完形填空】A new study found that inner-city kids living in neighborhoods with more green spacegained about 13% less weight over a two-year period than kids living amid more concrete and fewer trees. Such __62__ tell a powerful story. The obesity epidemic began in the 1980s, and many people __63__ it to increased portion sizes and inactivity, but that can't be everything. Fast foods and TVs have been __64__ us for a long time. "Most experts agree that the changes were __65__ to something in the environment," says social epidemiologist Thomas Glass of The Johns Hopkins Bloomberg School of Public Health. That something could be a __66__ of the green.The new research, __67__ in the American Journal of Preventive Medicine, isn't the first to associate greenery with better health, but it does get us closer __68__ identifying what works and why. At its most straightforward, a green neighborhood __69__ means more places for kids to play – which is __70__ since time spent outdoors is one of the strongest correlates of children's activity levels. But green space is good for the mind__71__: research by environmental psychologists has shown that it has cognitive __72__ for children with attention-deficit disorder. In one study, just reading __73__ in a green setting improved kids' symptoms.__74__ to grassy areas has also been linked to __75__ stress and a lower body mass index (体重指数) among adults. And an __76__ of 3,000 Tokyo residents associated walkable green spaces with greater longevity (长寿) among senior citizens.Glass cautions that most studies don't __77__ prove a causal link between greenness and health, but they're nonetheless helping spur action. In September the U. S. House of Representatives __78__ the delightfully named No Child Left Inside Act to encourage public initiatives aimed at exposing kids to the outdoors.Finding green space is not __79__ easy, and you may have to work a bit to get your family a little grass and trees. If you live in a suburb or a city with good parks, take__80__ of what's there. Your children in particular will love it – and their bodies and minds will be __81__ to you.16. [单选题] *A) findings(正确答案)B) thesesC) hypothesesD) abstracts17. [单选题] *A) adaptB) attribute(正确答案)C) allocateD) alternate18. [单选题] *A) amongstB) alongC) besideD) with(正确答案)19. [单选题] *A) gluedB) related(正确答案)C) trackedD) appointed20. [单选题] *A) scrapingB) denyingC) depressingD) shrinking(正确答案)21. [单选题] *A) published(正确答案)B) simulatedC) illuminatedD) circulated22. [单选题] *A)atB)to(正确答案)C)forD)over23. [单选题] *A) fullyB) simply(正确答案)C) seriouslyD) uniquely24. [单选题] *A)vital(正确答案)B)casualC)fatalD)subtle25. [单选题] *A) stillB) alreadyC) too(正确答案)D) yet26. [单选题] *A) benefits(正确答案)B) profitsC) revenuesD) awards27. [单选题] *A) outwardB) apartC) asideD) outside(正确答案)28. [单选题] *A) ImmunityB) ReactionC) Exposure(正确答案)D) Addiction29. [单选题] *A)muchB)less(正确答案)C)moreD)little30. [单选题] *A) installmentB) expeditionC) analysis(正确答案)D) option31. [单选题] *A) curiouslyB) negativelyC) necessarily(正确答案)D) comfortably32. [单选题] *A) relievedB) delegatedC) approved(正确答案)D) performed33. [单选题] *A)merelyB)always(正确答案)C)mainlyD)almost34. [单选题] *A) advantage(正确答案)B) exceptionC) measureD) charge35. [单选题] *A) elevatedB) mercifulC) contentedD) grateful(正确答案)【第三部分:阅读理解】Passage 1Will there ever be another Einstein? This is the undercurrent of conversation at Einstein memorial meetings throughout the year. A new Einstein will emerge, scientists say. But it may take a long time. After all, more than 200 years separated Einstein from his nearest rival, Isaac Newton.Many physicists say the next Einstein hasn’t been born yet, or is a baby now. That’s because the quest for a unified theory that would account for all the forces of nature has pushed current mathematics to its limits. New math must be created before the problem can be solved.But researchers say there are many other factors working against another Einsteinemerging anytime soon.For one thing, physics is a much different field today. In Einstein’s day, there were only a few thousand physicists worldwide, and the theoreticians who could intellectually rival Einstein probably would fit into a streetcar with seats to spare.Education is different, too. One crucial aspect of Einstein’s training that is overlooked is the years of philosophy he read as a teenager—Kant, Schopenhauer and Spinoza, among others. It taught him how to think independently and abstractly about space and time, and it wasn’t long before he became a philosopher himself.“The independence created by philosophical insight is—in my opinion—the mark of distinction between a mere artisan (工匠) or specialist and a real seeker after truth,”Einstein wrote in 1944.And he was an accomplished musician. The interplay between music and math is well known. Einstein would furiously play his violin as a way to think through a knotty physics problem.Today, universities have produced millions of physicists. There aren’t many jobs in science for them, so they go to Wall Street and Silicon Valley to apply their analytical skills to more practical—and rewarding—efforts.“Maybe there is an Einstein out there today,” said Columbia University physicist Brian Greene, “but it would be a lot harder for him to be heard.”Especially considering what Einstein was proposing.“The actual fabric of space and time curving? My God, what an idea!” Greene said at a recent gathering at the Aspen Institute. “It takes a certain type of person who will bang his head against the wall because you believe you’ll find the solution.”Perhaps the best examples are the five scientific papers Einstein wrote in his “miracle year” of 1905. These “thought experiments” were pages of calculations signed and submitted to the prestigious journal Annalen der Physik by a virtual unknown. There were no footnotes or citations.What might happen to such a submission today?“We all get papers like those in the mail,” Greene said. “We put them in the junk file.”36. What do scientists seem to agree upon, judging from the first two paragraphs? [单选题] *[A] Einstein pushed mathematics almost to its limits.[B] It will take another Einstein to build a unified theory.[C] No physicist is likely to surpass Einstein in the next 200 years.[D] It will be some time before a new Einstein emerges.(正确答案)37. What was critical to Einstein’s success? [单选题] *[A] His talent as an accomplished musician.[B] His independent and abstract thinking.(正确答案)[C] His untiring effort to fulfill his potential.[D] His solid foundation in math theory.38. What does the author tell us about physicists today? [单选题] *[A] They tend to neglect training in analytical skills.[B] They are very good at solving practical problems.[C] They attach great importance to publishing academic papers.[D] They often go into fields yielding greater financial benefits.(正确答案)39. What does Brian Greene imply by saying “... it would be a lot harder for him to be heard” (Lines 1-2, Para. 9)? [单选题] *[A] People have to compete in order to get their papers published.[B] It is hard for a scientist to have his papers published today.[C] Papers like Einstein’s would unlikely get published today.[D] Nobody will read papers on apparently ridiculous theories.(正确答案)40. When he submitted his papers in 1905, Einstein _______. [单选题] *[A] forgot to make footnotes and citations[B] was little known in academic circles(正确答案)[C] was known as a young genius in math calculations[D] knew nothing about the format of academic papersPassage 2The relationship between formal education and economic growth in poorcountries is widely misunderstood by economists and politicians alike. Progress in both areas is undoubtedly necessary for the social, political, and intellectual development of these and all other societies; however, the conventional view that education should be one of the very highest priorities for promoting rapid economic development in poor countries is wrong. We are fortunate that it is, because building new educational systems there and putting enough people through them to improve economic performance would require two or three generations. The findings of a research institution have consistently shown that workers in all countries can be trained on the job to achieve radically higher productivity and, as a result, radically higher standards ofliving.Ironically, the first evidence for this idea appeared in the United States. Not long ago, with the country entering a recession and Japan at its pre-bubble peak, the U.S. workforce was derided as poorly educated and one of the primary causes of the poor U.S. economic performance. Japan was, and remains, the global leader in automotive-assembly productivity. Yet the research revealed that the U.S. factories of Honda, Nissan, and Toyota achieved about 95 percent of the productivity of their Japanese counterparts - a result of the training that U.S. workers received on the job.More recently, while examining housing construction, the researchers discoveredthat illiterate, non-English-speaking Mexican workers in Houston, Texas, consistently met best-practice labor productivity standards despite the complexity of the building industry's work.What is the real relationship between education and economic development? Wehave to suspect that continuing economic growth promotes the development of education even when governments don't force it. After all, that's how education got started. When our ancestors were hunters and gatherers 10, 000 years ago, they didn't have time to wonder much about anything besides finding food. Only when humanity began to get its food in a more productive way was there time for other things.As education improved, humanity's productivity potential increased as well.When the competitive environment pushed our ancestors to achieve that potential,they could in tum afford more education. This increasingly high level of education is probably a necessary, but not a sufficient, condition for the complex political systems required by advanced economic performance. Thus poor countries might not be ableto escape their poverty traps without political changes that may be possible only with broader formal education. A lack of formal education, however, doesn't constrain the ability of the developing world's workforce to substantially improve productivity forthe foreseeable future. On the contrary, constraints on improving productivity explain why education isn't developing more quickly there than it is.41. The author holds in Paragraph 1 that the importance of education in poor [单选题] * countries[A] is subject to groundless doubts.[B] has fallen victim of bias.[C] is conventionally downgraded.[D] has been overestimated.(正确答案)42. It is stated in Paragraph 1 that the construction of a new educational system [单选题] *[A] challenges economists and politicians.[B] takes efforts of generations.(正确答案)[C] demands priority from the government.[D] requires sufficient labor force.43. A major difference between the Japanese and U.S. workforces is that [单选题] *[A] the Japanese workforce is better disciplined.[B] the Japanese workforce is more productive.(正确答案)[C] the U.S. workforce has a better education.[D] the U.S. workforce is more organized.44. The author quotes the example of our ancestors to show that education emerged [单选题] *[A] when people had enough time.[B] prior to better ways of finding food.[C] when people no longer went hungry.(正确答案)[D] as a result of pressure on government.45. According to the last paragraph, development of education [单选题] *[A] results directly from competitive environments.[B] does not depend on economic performance.[C] follows improved productivity.(正确答案)[D] cannot afford political changes.Passage 3A symbiotic relationship is an interaction between two or more species in which one species lives in or on another species. There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism. The first and the third can be key factors in the structure of a biological community; that is, all the populations oforganisms living together and potentially interacting in a particular area.Parasitism is a kind of predator-prey relationship in which one organism, the parasite, derives its food at the expense of its symbiotic associate, the host. Parasites are usually smaller than their hosts. An example of a parasite is a tapeworm that lives inside the intestines of a larger animal and absorbs nutrients from its host. Natural selection favors the parasites that are best able to find and feed on hosts. At the same time, defensive abilities of hosts are also selected for. As an example, plants make chemicals toxic to fungal and bacterial parasites, along with ones toxic to predatory animals (sometimes they are the same chemicals). In vertebrates, the immune system provides a multiple defense against internal parasites.At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. In 1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. Spread rapidly by mosquitoes, the virus devastated the rabbit population. The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.In contrast to parasitism, in commensalism, one partner benefits without significantly affecting the other. Few cases of absolute commensalism probably exist, because it is unlikely that one of the partners will be completely unaffected. Commensal associations sometimes involve one species' obtaining food that is inadvertently exposed by another. For instance, several kinds of birds feed on insects flushed out of the grass by grazing cattle. It is difficult to imagine how this could affect the cattle, but the relationship may help or hinder them in some way not yet recognized.The third type of symbiosis, mutualism, benefits both partners in the relationship Legume plants and their nitrogen-fixing bacteria, and the interactions between flowering plantsand their pollinators, are examples of mutualistic association. In the first case, the plants provide the bacteria with carbohydrates and other organic compounds, and the bacteria have enzymes that act as catalysts that eventually add nitrogen to the soil, enriching it. In the second case, pollinators (insects, birds) obtain food from the flowering plant, and the plant has its pollen distributed and seeds dispersed much more efficiently than they would be if they were carried by the wind only. Another example of mutualism would be the bull's horn acacia tree, which grows in Central and South America. The tree provides a place to live for ants of the genus Pseudomyrmex. The ants live in large, hollow thorns and eat sugar secreted by the tree. The ants also eat yellow structures at the tip of leaflets: these are protein rich and seem to have no function for the tree except to attract ants. The ants benefit the host tree by attacking virtually anything that touches it. They sting other insects and large herbivores (animals that eat only plants) and even clip surrounding vegetation that grows near the tree. When the ants are removed, the trees usually die, probably because herbivores damage them so much that they are unable to compete with surrounding vegetation for light and growing space.The complex interplay of species in symbiotic relationships highlights an important point about communities: Their structure depends on a web of diverse connections among organisms.46.Which of the following statements about commensalism can be inferred from paragraph 1? [单选题] *[A]It excludes interactions between more than two species.[B]It makes it less likely for species within a community to survive.[C]Its significance to the organization of biological communities is small.(正确答案)[D]Its role in the structure of biological populations is a disruptive one.47.According to paragraph 2. which of the following is true of the action of natural selection on hosts and parasites? [单选题] *[A]Hosts benefit more from natural selection than parasites do.[B]Both aggression in predators and defensive capacities in hosts are favored for species survival.(正确答案)[C]The ability to make toxic chemicals enables a parasite to find and isolate its host.[D]Larger size equips a parasite to prey on smaller host organisms.48.Which of the following can be concluded from the discussion in paragraph 3 about theAustralian rabbit population? [单选题] *[A]Human intervention may alter the host, the parasite. and the relationship between them.(正确答案)[B]The risks of introducing outside organisms into a biological community are not worth the benefits.[C]Humans should not interfere in host-parasite relationships.[D]Organisms that survive a parasitic attack do so in spite of the natural selection process.49.According to paragraph 3, all of the following characterize the way natural selectionstabilized the Australian rabbit population EXCEPT: [单选题] *[A]The most toxic viruses died with their hosts.[B]The surviving rabbits were increasingly immune to the virus.[C]The decline of the mosquito population caused the spread of the virus to decline.(正确答案)[D]Rabbits with specific genetic make-ups were favored.50.According to paragraph 5. which of the following is NOT true of the relationshipbetween the bull's horn acacia tree and the Pseudomyrmex ants? [单选题] *[A]Ants defend the host trees against the predatory actions of insects and animals.[B]The acacia trees are a valuable source of nutrition for the ants.[C]The ants enable the acacia tree to produce its own chemical defenses.(正确答案)[D]The ants protect the acacia from having to compete with surrounding vegetation.。
(完整版)大学物理(力学)试卷附答案
大 学 物 理(力学)试 卷一、选择题(共27分) 1.(本题3分)如图所示,A 、B 为两个相同的绕着轻绳的定滑轮.A 滑轮挂一质量为M 的物体,B 滑轮受拉力F ,而且F =Mg .设A 、B 两滑轮的角加速度分别为βA 和βB ,不计滑轮轴的摩擦,则有 (A) βA =βB . (B) βA >βB .(C) βA <βB . (D) 开始时βA =βB ,以后βA <βB . [ ] 2.(本题3分)几个力同时作用在一个具有光滑固定转轴的刚体上,如果这几个力的矢量和为零,则此刚体(A) 必然不会转动. (B) 转速必然不变.(C) 转速必然改变. (D) 转速可能不变,也可能改变. [ ] 3.(本题3分)关于刚体对轴的转动惯量,下列说法中正确的是 (A )只取决于刚体的质量,与质量的空间分布和轴的位置无关. (B )取决于刚体的质量和质量的空间分布,与轴的位置无关. (C )取决于刚体的质量、质量的空间分布和轴的位置.(D )只取决于转轴的位置,与刚体的质量和质量的空间分布无关. [ ] 4.(本题3分)一轻绳跨过一具有水平光滑轴、质量为M 的定滑轮,绳的两端分别悬有质量为m 1和m 2的物体(m 1<m 2),如图所示.绳与轮之间无相对滑动.若某时刻滑轮沿逆时针方向转动,则绳中的张力 (A) 处处相等. (B) 左边大于右边.(C) 右边大于左边. (D) 哪边大无法判断. [ ]5.(本题3分)将细绳绕在一个具有水平光滑轴的飞轮边缘上,现在在绳端挂一质量为m 的重物,飞轮的角加速度为β.如果以拉力2mg 代替重物拉绳时,飞轮的角加速度将 (A) 小于β. (B) 大于β,小于2 β.(C) 大于2 β. (D) 等于2 β. [ ] 6.(本题3分)花样滑冰运动员绕通过自身的竖直轴转动,开始时两臂伸开,转动惯量为J 0,角速度为ω0.然后她将两臂收回,使转动惯量减少为31J 0.这时她转动的角速度变为(A)31ω0. (B) ()3/1 ω0. (C) 3 ω0. (D) 3 ω0. [ ]7.(本题3分)关于力矩有以下几种说法:(1) 对某个定轴而言,内力矩不会改变刚体的角动量. (2) 作用力和反作用力对同一轴的力矩之和必为零.(3) 质量相等,形状和大小不同的两个刚体,在相同力矩的作用下,它们的角加速度一定相等.在上述说法中,(A) 只有(2) 是正确的.(B) (1) 、(2) 是正确的. (C) (2) 、(3) 是正确的.(D) (1) 、(2) 、(3)都是正确的. [ ] 8.(本题3分)一圆盘正绕垂直于盘面的水平光滑固定轴O 转动,如图射来两个质量相同,速度大小相同,方向相反并在一条直线上的子弹,子弹射入圆盘并且留在盘内,则子弹射入后的瞬间,圆盘的角速度ω (A) 增大. (B) 不变.(C) 减小. (D) 不能确定. [ ] 9.(本题3分)质量为m 的小孩站在半径为R 的水平平台边缘上.平台可以绕通过其中心的竖直光滑固定轴自由转动,转动惯量为J .平台和小孩开始时均静止.当小孩突然以相对于地面为v的速率在台边缘沿逆时针转向走动时,则此平台相对地面旋转的角速度和旋转方向分别为(A) ⎪⎭⎫⎝⎛=R JmR v 2ω,顺时针. (B) ⎪⎭⎫ ⎝⎛=R J mR v 2ω,逆时针. (C) ⎪⎭⎫ ⎝⎛+=R mR J mR v 22ω,顺时针. (D) ⎪⎭⎫⎝⎛+=R mR J mR v 22ω,逆时针. [ ]二、填空题(共25分)10.(本题3分)半径为20 cm 的主动轮,通过皮带拖动半径为50 cm 的被动轮转动,皮带与轮之间无相对滑动.主动轮从静止开始作匀角加速转动.在4 s 内被动轮的角速度达到8πrad ·s -1,则主动轮在这段时间内转过了________圈. 11.(本题5分)绕定轴转动的飞轮均匀地减速,t =0时角速度为ω 0=5 rad / s ,t =20 s 时角速度为ω = 0.8ω 0,则飞轮的角加速度β =______________,t =0到 t =100 s 时间内飞轮所转过的角度θ =___________________. 12.(本题4分)半径为30 cm 的飞轮,从静止开始以0.50 rad ·s -2的匀角加速度转动,则飞轮边缘上一点在飞轮转过240°时的切向加速度a t =________,法向加速度a n =_______________. 13.(本题3分)一个作定轴转动的物体,对转轴的转动惯量为J .正以角速度ω0=10 rad ·s -1匀速转动.现对物体加一恒定制动力矩 M =-0.5 N ·m ,经过时间t =5.0 s 后,物体停止了转动.物体的转动惯量J =__________. 14.(本题3分)一飞轮以600 rev/min 的转速旋转,转动惯量为2.5 kg ·m 2,现加一恒定的制动力矩使飞轮在1 s 内停止转动,则该恒定制动力矩的大小M =_________. 15.(本题3分)质量为m 、长为l 的棒,可绕通过棒中心且与棒垂直的竖直光滑固定轴O 在水平面内自由转动(转动惯量J =m l 2 / 12).开始时棒静止,现有一子弹,质量也是m ,在水平面内以速度v 0垂直射入棒端并嵌在其中.则子弹嵌入后棒的角速度ω =_____________________. 16.(本题4分)在一水平放置的质量为m 、长度为l 的均匀细杆上,套着一质量也为m 的套管B (可看作质点),套管用细线拉住,它到竖直的光滑固定轴OO '的距离为l 21,杆和套管所组成的系统以角速度ω0绕OO '轴转动,如图所示.若在转动过程中细线被拉断,套管将沿着杆滑动.在套管滑动过程中,该系统转动的角速度ωmm m0v 俯视图与套管离轴的距离x 的函数关系为_______________.(已知杆本身对OO '轴的转动惯量为231ml )三、计算题(共38分) 17.(本题5分)如图所示,一圆盘绕通过其中心且垂直于盘面的转轴,以角速度ω作定轴转动,A 、B 、C 三点与中心的距离均为r .试求图示A 点和B 点以及A 点和C 点的速度之差B A v v ϖϖ-和C A v v ϖϖ-.如果该圆盘只是单纯地平动,则上述的速度之差应该如何? 18.(本题5分)一转动惯量为J 的圆盘绕一固定轴转动,起初角速度为ω0.设它所受阻力矩与转动角速度成正比,即M =-k ω (k 为正的常数),求圆盘的角速度从ω0变为021ω时所需的时间.19.(本题10分)一轻绳跨过两个质量均为m 、半径均为r 的均匀圆盘状定滑轮,绳的两端分别挂着质量为m 和2m 的重物,如图所示.绳与滑轮间无相对滑动,滑轮轴光滑.两个定滑轮的转动惯量均为221mr .将由两个定滑轮以及质量为m 和2m 的重物组成的系统从静止释放,求两滑轮之间绳内的张力.20.(本题8分)如图所示,A 和B 两飞轮的轴杆在同一中心线上,设两轮的转动惯量分别为 J =10 kg ·m 2 和 J =20 kg ·m 2.开始时,A 轮转速为600 rev/min ,B 轮静止.C 为摩擦啮合器,其转动惯量可忽略不计.A 、B 分别与C 的左、右两个组件相连,当C 的左右组件啮合时,B 轮得到加速而A 轮减速,直到两轮的转速相等为止.设轴光滑,求:(1) 两轮啮合后的转速n ;(2) 两轮各自所受的冲量矩.21.(本题10分)空心圆环可绕光滑的竖直固定轴AC 自由转动,转动惯量为J 0,环的半径为R ,初始时环的角速度为ω0.质量为m 的小球静止在环内最高处A 点,由于某种微小干扰,小球沿环向下滑动,问小球滑到与环心O 在同一高度的B 点和环的最低处的C 点时,环的角速度及小球相对于环的速度各为多大?(设环的内壁和小球都是光滑的,小球可视为质点,环截面半径r <<R .) 回答问题(共10分) 22.(本题5分)绕固定轴作匀变速转动的刚体,其上各点都绕转轴作圆周运动.试问刚体上任意一点是否有切向加速度?是否有法向加速度?切向加速度和法向加速度的大小是否变化?理由如何? 23.(本题5分)一个有竖直光滑固定轴的水平转台.人站立在转台上,身体的中心轴线与转台竖直轴线重合,两臂伸开各举着一个哑铃.当转台转动时,此人把两哑铃水平地收缩到胸前.在这一收缩过程中,(1) 转台、人与哑铃以及地球组成的系统机械能守恒否?为什么? (2) 转台、人与哑铃组成的系统角动量守恒否?为什么?(3) 每个哑铃的动量与动能守恒否?为什么?大 学 物 理(力学) 试 卷 解 答一、选择题(共27分)C D C C C D B C A 二、填空题(共25分) 10.(本题3分)20 参考解: r 1ω1=r 2ω2 , β1 = ω1 / t 1 ,θ1=21121t β 21211412ωθr r n π=π=4825411⨯π⨯⨯π=t =20 rev11.(本题5分)-0.05 rad ·s -2 (3分)250 rad (2分)12.(本题4分)0.15 m ·s -2(2分)1.26 m ·s -2(2分)参考解: a t =R ·β =0.15 m/s 2 a n =R ω 2=R ·2βθ =1.26 m/s 2 13.(本题3分)0.25 kg ·m 2(3分) 14.(本题3分)157N·m (3分) 15.(本题3分)3v 0/(2l )16.(本题4分)()2202347xl l +ω三、计算题(共38分) 17.(本题5分)解:由线速度r ϖϖϖ⨯=ωv 得A 、B 、C 三点的线速度ωr C B A ===v v v ϖϖϖ 1分各自的方向见图.那么,在该瞬时 ωr A B A 22==-v v v ϖϖϖθ=45° 2分同时 ωr A C A 22==-v v v ϖϖϖ方向同A v ϖ. 1分平动时刚体上各点的速度的数值、方向均相同,故0=-=-C A B A v v v v ϖϖϖϖ 1分 [注]此题可不要求叉积公式,能分别求出 A v ϖ、B v ϖ的大小,画出其方向即可. 18.(本题5分)解:根据转动定律: J d ω / d t = -k ω∴t Jkd d -=ωω2分 两边积分:⎰⎰-=t t Jk 02/d d 100ωωωω得 ln2 = kt / J∴ t =(J ln2) / k 3分19.(本题10分)θ BC AωB v ϖC v ϖA v ϖB v ϖ-A v ϖB v v A ϖϖ- -C v ϖ A v ϖ解:受力分析如图所示. 2分 2mg -T 1=2ma 1分 T 2-mg =ma 1分T 1 r -T r =β221mr 1分T r -T 2 r =β221mr 1分a =r β2分解上述5个联立方程得: T =11mg / 8 2分20.(本题8分)解:(1) 选择A 、B 两轮为系统,啮合过程中只有内力矩作用,故系统角动量守恒1分 J A ωA +J B ωB = (J A +J B )ω, 2分 又ωB =0得 ω ≈ J A ωA / (J A +J B ) = 20.9 rad / s 转速 ≈n 200 rev/min 1分(2) A 轮受的冲量矩⎰t MAd = J A (ω -ωA ) = -4.19×10 2 N ·m ·s 2分负号表示与A ωϖ方向相反. B 轮受的冲量矩⎰t MBd = J B (ω - 0) = 4.19×102 N ·m ·s 2分方向与A ωϖ相同.21.(本题10分)解:选小球和环为系统.运动过程中所受合外力矩为零,角动量守恒.对地球、小球和环系统机械能守恒.取过环心的水平面为势能零点.两个守恒及势能零点各1分,共3分小球到B 点时: J 0ω0=(J 0+mR 2)ω ① 1分()22220200212121BR m J mgR J v ++=+ωωω ② 2分 式中v B 表示小球在B 点时相对于地面的竖直分速度,也等于它相对于环的速度.由式①得:ω=J 0ω 0 / (J 0 + mR 2) 1分代入式②得222002J mR RJ gR B ++=ωv 1分 当小球滑到C 点时,由角动量守恒定律,系统的角速度又回复至ω0,又由机械能守恒定律知,小球在C 的动能完全由重力势能转换而来.即:()R mg m C 2212=v , gR C 4=v 2分四、问答题(共10分) 22.(本题5分)答:设刚体上任一点到转轴的距离为r ,刚体转动的角速度为ω,角加速度为β,则由运动学关系有:切向加速度a t =r β 1分 法向加速度a n =r ω2 1分对匀变速转动的刚体来说β=d ω / d t =常量≠0,因此d ω=βd t ≠0,ω 随时间变化,即ω=ω (t ). 1分所以,刚体上的任意一点,只要它不在转轴上(r ≠0),就一定具有切向加速度和法向加速度.前者大小不变,后者大小随时间改变. 2分(未指出r ≠0的条件可不扣分)m 2m βT 2 2P ϖ1P ϖTa T 1a23.(本题5分)答:(1) 转台、人、哑铃、地球系统的机械能不守恒. 1分因人收回二臂时要作功,即非保守内力的功不为零,不满足守恒条件. 1分 (2) 转台、人、哑铃系统的角动量守恒.因系统受的对竖直轴的外力矩为零. 1分(3) 哑铃的动量不守恒,因为有外力作用. 1分 哑铃的动能不守恒,因外力对它做功. 1分 刚体题一 选择题 1.(本题3分,答案:C ;09B )一轻绳跨过一具有水平光滑轴、质量为M 的定滑轮,绳的两端分别悬有质量为m 1和m 2的物体(m 1<m 2),如图所示.绳与轮之间无相对滑动.若某时刻滑轮沿逆时针方向转动,则绳中的张力 (A) 处处相等. (B) 左边大于右边.(C) 右边大于左边. (D) 哪边大无法判断. 2.(本题3分,答案:D ;09A ) 花样滑冰运动员绕通过自身的竖直轴转动,开始时两臂伸开,转动惯量为J 0,角速度为ω0.然后她将两臂收回,使转动惯量减少为31J 0.这时她转动的角速度变为(A)31ω0. (B) ()3/1 ω0. (C)3 ω0. (D) 3 ω0.3.( 本题3分,答案:A ,08A )1.均匀细棒OA 可绕通过其一端O 而与棒垂直的水平固定光滑轴转动,如图所示,今使棒从水平位置由静止开始自由下落,在棒摆动到竖立位置的过程中,下述说法哪一种是正确的?(A) 角速度从小到大,角加速度从大到小. (B) 角速度从小到大,角加速度从小到大. (C) 角速度从大到小,角加速度从大到小.(D) 角速度从大到小,角加速度从小到大. 二、填空题1(本题4分,08A, 09B )一飞轮作匀减速运动,在5s 内角速度由40πrad/s 减少到10π rad/s ,则飞轮在这5s 内总共转过了 圈,飞轮再经 的时间才能停止转动。
大学 物理试题 含答案 1.1
振动一长为l 的均匀细棒悬于通过其一端的光滑水平固定轴上,(如图所示),作成一复摆.已知细棒绕通过其一端的轴的转动惯量231ml J =,此摆作微小振动的周期为(A)g l π2. (B) g l22π.(C)g l 322π. (D) g l 3π. []2.s )21一质点作简谐振动.其运动速度与时间的曲线如图所示.若质点的振动规律用余弦函数描述,则其初相应为(A) π/6. (B) 5π/6. (C) -5π/6.(D) -π/6. (E) -2π/3.[]3. 一质点沿x 轴作简谐振动,振动方程为)312cos(1042π+π⨯=-t x (SI). 从t = 0时刻起,到质点位置在x = -2 cm 处,且向x 轴正方向运动的最短时间间隔为(A) s 81 (B) s 61 (C) s41(D) s 31 (E) s21[]4. 一弹簧振子,重物的质量为m ,弹簧的劲度系数为k ,该振子作振幅为A 的简谐振动.当重物通过平衡位置且向规定的正方向运动时,开始计时.则其振动方程为:(A))21/(cos π+=t m k A x (B) )21/cos(π-=t m k A x(C))π21/(cos +=t k m A x (D) )21/cos(π-=t k m A x (E) t m /k A x cos =[]5. 一劲度系数为k 的轻弹簧,下端挂一质量为m 的物体,系统的振动周期为T 1.若将此弹簧截去一半的长度,下端挂一质量为m21的物体,则系统振动周期T 2等于 (A) 2 T 1 (B) T 1 (C) T 12/(D) T 1 /2 (E) T 1 /4 []6. 一质点在x 轴上作简谐振动,振辐A = 4 cm ,周期T = 2 s ,其平衡位置取作坐标原点.若t = 0时刻质点第一次通过x = -2 cm 处,且向x 轴负方向运动,则质点第二次通过x = -2 cm 处的时刻为(A) 1 s . (B) (2/3) s .(C) (4/3) s . (D) 2 s .[]7. 两个同周期简谐振动曲线如图所示.x 1的相位比x 2的相位 (A) 落后π/2. (B) 超前π/2. (C) 落后π . (D) 超前π. [](B)-8.一个质点作简谐振动,振幅为A ,在起始时刻质点的位移为A 21,且向x 轴的正方向运动,代表此简谐振动的旋转矢量图为[]9.一简谐振动曲线如图所示.则振动周期是 (A) 2.62 s . (B) 2.40 s .(C) 2.20 s.(D) 2.00 s.]10.一简谐振动用余弦函数表示,其振动曲线如图所示,则此简谐振动的三个特征量为A =_____________;ω =________________;φ =_______________.Array11.已知三个简谐振动曲线如图所示,则振动方程分别为:x1 =______________________,x2 = _____________________,x3 =_______________________.12.一简谐振动曲线如图所示,则由图可确定在t = 2s时刻质点的位移为____________________,速度为__________________.·--13.两个同方向的简谐振动曲线如图所示.合振动的振幅为_______________________________,合振动的振动方程为________________________________.14. 一物体作余弦振动,振幅为15³10-2 m,角频率为6π s-1,初相为0.5 π,则振动方程为x = ________________________(SI).-15.一简谐振动的振动曲线如图所示.求振动方程.16. 一质点同时参与两个同方向的简谐振动,其振动方程分别为x1=5³10-2cos(4t + π/3) (SI) , x2 =3³10-2sin(4t-π/6)(SI)画出两振动的旋转矢量图,并求合振动的振动方程.17. 两个同方向的简谐振动的振动方程分别为x1 = 4³10-2cos2π)81(+t(SI), x2 = 3³10-2cos2π)41(+t(SI)求合振动方程.18. 质量m= 10 g的小球与轻弹簧组成的振动系统,按)318cos(5.0π+π=tx的规律作自由振动,式中t以秒作单位,x以厘米为单位,求(1) 振动的角频率、周期、振幅和初相;(2) 振动的速度、加速度的数值表达式;(3) 振动的能量E ;(4) 平均动能和平均势能.19. 在一竖直轻弹簧下端悬挂质量m = 5 g 的小球,弹簧伸长∆l = 1 cm 而平衡.经推动后,该小球在竖直方向作振幅为A = 4 cm 的振动,求 (1) 小球的振动周期; (2) 振动能量.1.(C)2. (C)3. (E)4.(B) v 5. (D) 6. (B) 7. (B) 8. (B) 9. (B)10. 10 cm 1分 (π/6) rad/s 1分 π/3 1分11. 0.1cos πt (SI) 1分0.1)21cos(π-πt (SI) 1分 0.1)cos(π±πt (SI) 1分12.0 1分 3π cm/s 2分13.|A 1 - A 2|1分)212cos(12π+π-=t T A A x 2分 14.)216cos(10152π+π⨯-t 3分 15. 解:(1)设振动方程为)cos(φω+=t A x由曲线可知A = 10 cm , t = 0,φcos 1050=-=x ,0sin 100<-=φωv解上面两式,可得φ = 2π/3 2分由图可知质点由位移为x 0 = -5 cm 和v 0< 0的状态到x = 0和v > 0的状态所需时间t = 2 s ,代入振动方程得)3/22cos(100π+=ω (SI)则有2/33/22π=π+ω,∴ω = 5 π/12 2分 故所求振动方程为)3/212/5cos(1.0π+π=t x (SI) 1分16.xO ωωπ/3-2π/3A1A 2A解:x 2= 3³10-2 sin(4t -π/6) = 3³10-2cos(4t -π/6-π/2) = 3³10-2cos(4t - 2π/3).作两振动的旋转矢量图,如图所示.图2分由图得:合振动的振幅和初相分别为A = (5-3)cm = 2 cm ,φ = π/3. 2分合振动方程为x = 2³10-2cos(4t +π/3) (SI) 1分17. 解:由题意x 1 = 4³10-2cos)42(π+πt (SI) x 2 =3³10-2cos)22(π+πt (SI) 按合成振动公式代入已知量,可得合振幅及初相为22210)4/2/cos(2434-⨯π-π++=A m= 6.48³10-2 m 2分)2/cos(3)4/cos(4)2/sin(3)4/sin(4arctgπ+ππ+π=φ=1.12 rad 2分合振动方程为x = 6.48³10-2 cos(2πt +1.12) (SI) 2分18. 解:(1) A = 0.5 cm ;ω = 8π s -1;T = 2π/ω = (1/4) s ;φ = π/3 2分(2))318sin(1042π+π⨯π-==-t xv (SI) )318cos(103222π+π⨯π-==-t xa (SI) 2分(3)2222121A m kA E E E P K ω==+==7.90³10-5 J 3分 (4) 平均动能⎰=TK tm T E 02d 21)/1(v ⎰π+π⨯π-=-Ttt m T 0222d )318(sin )104(21)/1(= 3.95³10-5 J = E21 同理EE P 21== 3.95³10-5 J 3分19. 解:(1))//(2/2/2l g m k m T ∆π=π=π=ω= 0.201 s 3分 (2) 22)/(2121A l mg kA E ∆=== 3.92³10-3 J 2分波动1. []2.一平面简谐波的表达式为)3cos(1.0π+π-π=x t y (SI) ,t = 0时的波形曲线如图所示,则(A) O 点的振幅为-0.1 m . (B) 波长为3 m .(C) a 、b 两点间相位差为π21.(D) 波速为9 m/s .[]3. 若一平面简谐波的表达式为)cos(Cx Bt A y -=,式中A 、B 、C 为正值常量,则 (A) 波速为C . (B) 周期为1/B .(C) 波长为 2π /C . (D) 角频率为2π /B .[]4.如图所示,一平面简谐波沿x 轴正向传播,已知P 点的振动方程为)cos(0φω+=t A y ,则波的表达式为(A)}]/)([cos{0φω+--=u l x t A y .(B)})]/([cos{0φω+-=u x t A y . (C) )/(cos u x t A y -=ω. (D)}]/)([cos{0φω+-+=u l x t A y .[](m)5.图示一简谐波在t = 0时刻的波形图,波速u = 200 m/s ,则图中O 点的振动加速度的表达式为(A))21cos(4.02π-ππ=t a (SI). (B))23cos(4.02π-ππ=t a (SI). (C))2cos(4.02π-ππ-=t a (SI). (D))212cos(4.02π+ππ-=t a (SI) []6. 在波长为λ的驻波中,两个相邻波腹之间的距离为 (A) λ /4. (B) λ /2. (C) 3λ /4. (D) λ .[]7. 一横波沿绳子传播时, 波的表达式为)104cos(05.0t x y π-π= (SI),则 (A) 其波长为0.5 m . (B) 波速为5 m/s . (C) 波速为25 m/s . (D) 频率为2 Hz .[]8.图示一简谐波在t = 0时刻的波形图,波速u = 200 m/s ,则P 处质点的振动速度表达式为(A) )2cos(2.0π-ππ-=t v (SI). (B) )cos(2.0π-ππ-=t v (SI). (C) )2/2cos(2.0π-ππ=t v (SI).(D) )2/3cos(2.0π-ππ=t v (SI).[]9.一平面简谐波沿x 轴正方向传播,波速 u = 100 m/s ,t = 0时刻的波形曲线如图所示.可知波长λ = ____________;振幅A = __________;频率ν = ____________.10. 一平面简谐波的表达式为)37.0125cos(025.0x t y -= (SI),其角频率ω =__________________________,波速u =______________________,波长λ = _________________.11.-图为t = T / 4 时一平面简谐波的波形曲线,则其波的表达式为______________________________________________.12. 在简谐波的一条射线上,相距0.2 m 两点的振动相位差为π /6.又知振动周期为0.4 s ,则波长为_________________,波速为________________.13. 在同一媒质中两列频率相同的平面简谐波的强度之比I 1 / I 2 = 16,则这两列 波的振幅之比是A 1 / A 2 = ____________________.14.一列平面简谐波在媒质中以波速u = 5 m/s沿x轴正向传播,原点O处质元的振动曲线如图所示.(1) 求解并画出x = 25 m处质元的振动曲线.(2) 求解并画出t = 3 s时的波形曲线.A B xu15.如图,一平面波在介质中以波速u = 20 m/s沿x轴负方向传播,已知A点的振动方程为tyπ⨯=-4cos1032(SI).(1) 以A点为坐标原点写出波的表达式;(2) 以距A点5 m处的B点为坐标原点,写出波的表达式.16. 某质点作简谐振动,周期为2 s,振幅为0.06 m,t = 0 时刻,质点恰好处在负向最大位移处,求(1) 该质点的振动方程;(2) 此振动以波速u = 2 m/s沿x轴正方向传播时,形成的一维简谐波的波动表达式,(以该质点的平衡位置为坐标原点);(3) 该波的波长.17. 一振幅为10 cm,波长为200 cm的一维余弦波.沿x轴正向传播,波速为100 cm/s,在t = 0时原点处质点在平衡位置向正位移方向运动.求(1) 原点处质点的振动方程.(2) 在x = 150 cm 处质点的振动方程.18. 已知波长为λ 的平面简谐波沿x 轴负方向传播.x = λ /4处质点的振动方程为ut A y ⋅π=λ2cos(SI)(1) 写出该平面简谐波的表达式..(2) 画出t = T 时刻的波形图.波动1.(B) 2. (C) 3. (C) 4. (A) 5. (D) 6. (B) 7. (A) 8. (A) 9. 0.8 m 2分 0.2 m 1分 125 Hz 2分10. 125 rad/s 1分 338 m/s 2分 17.0 m 2分11. ])330/(165cos[10.0π--π=x t y (SI) 3分12. 2.4 m 2分6.0 m/s 2分13. 4 3分 14. 解:(1) 原点O 处质元的振动方程为)2121cos(1022π-π⨯=-t y , (SI) 2分 波的表达式为)21)5/(21cos(1022π--π⨯=-x t y , (SI) 2分 x = 25 m 处质元的振动方程为)321cos(1022π-π⨯=-t y , (SI)振动曲线见图 (a) 2分(2) t = 3 s 时的波形曲线方程)10/cos(1022x y π-π⨯=-, (SI) 2分t (s)O -2³10-21y (m)234(a)波形曲线见图 2分2³15. 解:(1) 坐标为x 点的振动相位为)]/([4u x t t +π=+φω)]/([4u x t +π=)]20/([4x t +π= 2分波的表达式为)]20/([4cos 1032x t y +π⨯=- (SI) 2分 (2) 以B 点为坐标原点,则坐标为x 点的振动相位为]205[4-+π='+x t t φω (SI) 2分 波的表达式为])20(4cos[1032π-+π⨯=-xt y (SI) 2分16. 解:(1) 振动方程)22cos(06.00π+π=ty )cos(06.0π+π=t (SI) 3分 (2) 波动表达式])/(cos[06.0π+-π=u x t y 3分])21(cos[06.0π+-π=x t (SI)(3) 波长4==uT λ m 2分17. 解:(1)振动方程:)cos(0φω+=t A y A = 10 cm , ω = 2πν = π s -1,ν = u / λ = 0.5 Hz 初始条件:y (0, 0) = 00)0,0(>y 得π-=210φ故得原点振动方程:)21cos(10.0π-π=t y (SI) 2分 2) x = 150 cm 处相位比原点落后π23,所以)2321cos(10.0π-π-π=t y )2cos(10.0π-π=t (SI) 3分也可写成t y π=cos 10.0 (SI)图A解:(1) 如图A ,取波线上任一点P ,其坐标设为x ,由波的传播特性,P 点的振动落后于λ /4处质点的振动. 2分 该波的表达式为)]4(22cos[x ut A y -π-π=λλλ )222cos(x ut A λλπ+π-π= (SI) 3分 (2) t = T 时的波形和t = 0时波形一样. t = 0时)22cos(x A y λπ+π-=)22cos(π-π=x A λ 2分按上述方程画的波形图见图B . 3分波动光学1. 在单缝夫琅禾费衍射实验中,波长为λ的单色光垂直入射在宽度为a =4 λ的单缝上,对应于衍射角为30°的方向,单缝处波阵面可分成的半波带数目为(A) 2 个. (B) 4 个.(C) 6 个. (D) 8 个.[]2. 波长为λ的单色平行光垂直入射到一狭缝上,若第一级暗纹的位置对应的衍射角为θ=±π / 6,则缝宽的大小为(A) λ / 2. (B) λ.(C) 2λ. (D) 3 λ.[]3. 在夫琅禾费单缝衍射实验中,对于给定的入射单色光,当缝宽度变小时,除中央亮纹的中心位置不变外,各级衍射条纹(A) 对应的衍射角变小. (B) 对应的衍射角变大. (C) 对应的衍射角也不变. (D) 光强也不变.[]4. 一束平行单色光垂直入射在光栅上,当光栅常数(a + b )为下列哪种情况时(a 代表每条缝的宽度),k =3、6、9 等级次的主极大均不出现? (A) a +b =2 a . (B) a +b =3 a .(C) a +b =4 a . (A) a +b =6 a .[]5. 在光栅光谱中,假如所有偶数级次的主极大都恰好在单缝衍射的暗纹方向上,因而实际上不出现,那么此光栅每个透光缝宽度a 和相邻两缝间不透光部分宽度b 的关系为(A) a=21b . (B) a=b .(C) a=2b . (D) a=3 b .[]6. 在双缝干涉实验中,用单色自然光,在屏上形成干涉条纹.若在两缝后放一个偏振片,则(A) 干涉条纹的间距不变,但明纹的亮度加强. (B) 干涉条纹的间距不变,但明纹的亮度减弱. (C) 干涉条纹的间距变窄,且明纹的亮度减弱. (D) 无干涉条纹.[]7. 一束光是自然光和线偏振光的混合光,让它垂直通过一偏振片.若以此入射光束为轴旋转偏振片,测得透射光强度最大值是最小值的5倍,那么入射光束中自然光与线偏振光的光强比值为(A) 1 / 2. (B) 1 / 3.(C) 1 / 4. (D) 1 / 5.[]8. 如果两个偏振片堆叠在一起,且偏振化方向之间夹角为60°,光强为I 0的自然光垂直入射在偏振片上,则出射光强为 (A) I 0 / 8. (B) I 0 / 4.(C) 3 I 0 / 8. (D) 3 I 0 / 4.[]9. 使一光强为I 0的平面偏振光先后通过两个偏振片P 1和P 2.P 1和P 2的偏振化方向与原入射光光矢量振动方向的夹角分别是α 和90°,则通过这两个偏振片后的光强I 是(A) 21I 0cos 2α . (B) 0.(C) 41I 0sin 2(2α). (D) 41I 0sin 2α . (E) I 0 cos 4α .[]10. 光强为I0的自然光依次通过两个偏振片P1和P2.若P1和P2的偏振化方向的夹角α=30°,则透射偏振光的强度I是(A) I0 / 4.(B)3I0 / 4.(C)3I0 / 2.(D) I0 / 8.(E) 3I0 / 8.[]11. n1n2n3用波长为λ的单色光垂直照射折射率为n2的劈形膜(如图)图中各部分折射率的关系是n1<n2<n3.观察反射光的干涉条纹,从劈形膜顶开始向右数第5条暗条纹中心所对应的厚度e=____________________.12. 波长λ=600 nm的单色光垂直照射到牛顿环装置上,第二个明环与第五个明环所对应的空气膜厚度之差为____________nm.(1 nm=10-9 m)13. 若在迈克耳孙干涉仪的可动反射镜M移动0.620 mm过程中,观察到干涉条纹移动了2300条,则所用光波的波长为_____________nm.(1 nm=10-9 m)14. 用迈克耳孙干涉仪测微小的位移.若入射光波波长λ=628.9 nm,当动臂反射镜移动时,干涉条纹移动了2048条,反射镜移动的距离d=________.15. 已知在迈克耳孙干涉仪中使用波长为l的单色光.在干涉仪的可动反射镜移动距离d的过程中,干涉条纹将移动________________条.16. 在迈克耳孙干涉仪的一条光路中,插入一块折射率为n,厚度为d的透明薄片.插入这块薄片使这条光路的光程改变了_______________.17. 一束平行的自然光,以60°角入射到平玻璃表面上.若反射光束是完全偏振的,则透射光束的折射角是____________________________;玻璃的折射率为________________.如图所示,一束自然光入射到折射率分别为n1和n2的两种介质的交界面上,发生反射和折射.已知反射光是完全偏振光,那么折射角r 的值为_______________________.19. 假设某一介质对于空气的临界角是45°,则光从空气射向此介质时的布儒 斯特角是_______________________.20. 当一束自然光在两种介质分界面处发生反射和折射时,若反射光为线偏振 光,则折射光为____________偏振光,且反射光线和折射光线之间的夹角为 ___________.21. 在双缝干涉实验中,波长λ=550 nm 的单色平行光垂直入射到缝间距a =2³10-4m 的双缝上,屏到双缝的距离D =2 m .求:(1) 中央明纹两侧的两条第10级明纹中心的间距;(2) 用一厚度为e =6.6³10-5 m 、折射率为n =1.58的玻璃片覆盖一缝后,零级明纹将移到原来的第几级明纹处?(1 nm = 10-9 m)22. 在双缝干涉实验中,双缝与屏间的距离D =1.2m ,双缝间距d =0.45 mm ,若测得屏上干涉条纹相邻明条纹间距为1.5mm ,求光源发出的单色光的波长l .在如图所示的牛顿环装置中,把玻璃平凸透镜和平面玻璃(设玻璃折射率n 1=1.50)之间的空气(n 2=1.00)改换成水(2n '=1.33),求第k 个暗环半径的相对改变量()k k k r r r /'-.24. 一衍射光栅,每厘米200条透光缝,每条透光缝宽为a=2³10-3cm ,在光栅后放一焦距f=1 m 的凸透镜,现以λ=600 nm (1 nm =10-9 m)的单色平行光垂直照射光栅,求:(1) 透光缝a 的单缝衍射中央明条纹宽度为多少? (2) 在该宽度内,有几个光栅衍射主极大?1. (B)2. (C)3. (B)4.(B)5.(B)6.(B)7.(A)8.(A)9.(C)10. (E)11.249n λ3分 12.900 3分13. 539.1 3分 14. 0.644mm 3分15. 2d /l 3分 16. 2( n - 1) d 3分 17. 30︒3分1.73 2分 18. π / 2-arctg(n 2 / n 1) 3分19.54.7° 3分20. 部分2分 π / 2 (或90°) 1分21. 解:(1) ∆x =20 D λ / a 2分=0.11 m 2分(2) 覆盖云玻璃后,零级明纹应满足(n -1)e +r 1=r 2 2分 设不盖玻璃片时,此点为第k 级明纹,则应有r 2-r 1=k λ 2分所以 (n -1)e = k λk =(n -1) e / λ=6.96≈7零级明纹移到原第7级明纹处 2分22. 解:根据公式x =k λ D / d相邻条纹间距∆x =D λ / d则λ=d ∆x / D 3分=562.5 nm . 2分23. 解:在空气中时第k 个暗环半径为λkR r k = , (n 2 = 1.00) 3分充水后第k 个暗环半径为2/n kR r k '='λ , (2n ' = 1.33) 3分 干涉环半径的相对变化量为()λλkR n kR r r r kk k 2/11'-='-2/11n '-==13.3% 2分24. 解:(1)a sin ϕ= k λ tg ϕ= x / f 2分当x <<f 时,ϕϕϕ≈≈sin tg , a x / f = k λ , 取k = 1有x = f l / a = 0.03 m 1分∴中央明纹宽度为∆x = 2x = 0.06m 1分(2)( a + b ) sin ϕλk '=='k ( a +b ) x / (f λ)= 2.5 2分取k '= 2,共有k '= 0,±1,±2 等5个主极大 2分量子物理1. 用频率为ν1的单色光照射某种金属时,测得饱和电流为I 1,以频率为ν2的单色光照射该金属时,测得饱和电流为I 2,若I 1> I 2,则 (A) ν1 >ν2. (B) ν1<ν2.(C) ν1=ν2. (D) ν1与ν2的关系还不能确定.[]2. 已知某单色光照射到一金属表面产生了光电效应,若此金属的逸出电势是U 0 (使电子从金属逸出需作功eU 0),则此单色光的波长λ必须满足:(A) λ≤)/(0eU hc . (B) λ ≥)/(0eU hc .(C) λ≤)/(0hc eU . (D) λ ≥)/(0hc eU .[]3.一定频率的单色光照射在某种金属上,测出其光电流的曲线如图中实线所示.然后在光强度不变的条件下增大照射光的频率,测出其光电流的曲线如图中虚线所示.满足题意的图是:[]4. 在康普顿效应实验中,若散射光波长是入射光波长的 1.2倍,则散射光光子能量ε与反冲电子动能E K 之比ε / E K 为(A) 2. (B) 3. (C) 4. (D) 5.[] 5. 具有下列哪一能量的光子,能被处在n = 2的能级的氢原子吸收? (A) 1.51 eV . (B) 1.89 eV .(C) 2.16 eV . (D) 2.40 eV .[] 6. 若α粒子(电荷为2e )在磁感应强度为B 均匀磁场中沿半径为R 的圆形轨道运动,则α粒子的德布罗意波长是(A) )2/(eRB h . (B) )/(eRB h .(C) )2/(1eRBh . (D) )/(1eRBh .[] 7. 直接证实了电子自旋存在的最早的实验之一是(A) 康普顿实验. (B) 卢瑟福实验.(C) 戴维孙-革末实验. (D) 斯特恩-革拉赫实验.[]8. 关于不确定关系 ≥∆∆x p x ()2/(π=h ,有以下几种理解: (1) 粒子的动量不可能确定. (2) 粒子的坐标不可能确定.(3) 粒子的动量和坐标不可能同时准确地确定.(4) 不确定关系不仅适用于电子和光子,也适用于其它粒子. 其中正确的是:(A) (1),(2). (B) (2),(4).(C) (3),(4). (D) (4),(1). [] 9. 下列各组量子数中,哪一组可以描述原子中电子的状态?(A) n = 2,l = 2,m l = 0,21=s m . (B) n = 3,l = 1,m l =-1,21-=s m . (C) n = 1,l = 2,m l = 1,21=s m . (D) n = 1,l = 0,m l = 1,21-=s m .[] 10. 氢原子中处于2p 状态的电子,描述其量子态的四个量子数(n ,l ,m l ,m s )可能取的值为(A) (2,2,1,21-). (B) (2,0,0,21).(C) (2,1,-1,21-). (D) (2,0,1,21).[]11.光子波长为λ,则其能量=____________;动量的大小 =_____________;质量=_________________ .12.波长为λ =1 Å的X 光光子的质量为_____________kg . (h =6.63³10-34 J ²s)13. 原子内电子的量子态由n 、l 、m l 及m s 四个量子数表征.当n 、l 、m l 一定时, 不同的量子态数目为__________________;当n 、l 一定时,不同的量子态数目 为____________________;当n 一定时,不同的量子态数目为_______.14.频率为 100 MHz 的一个光子的能量是_______________________,动量的 大小是______________________. (普朗克常量h =6.63³10-34 J ²s)15. 某金属产生光电效应的红限为ν0,当用频率为ν (ν >ν0 )的单色光照射该金属时,从金属中逸出的光电子(质量为m )的德布罗意波长为________________. 16. 玻尔的氢原子理论的三个基本假设是: (1)____________________________________, (2)____________________________________, (3)____________________________________.17.氢原子中电子从n = 3的激发态被电离出去,需要的能量为_________eV .18.如图所示,某金属M 的红限波长λ0 = 260 nm (1 nm = 10-9 m)今用单色紫外线照射该金属,发现有光电子放出,其中速度最大的光电子可以匀速直线地穿过互相垂直的均匀电场(场强E = 5³103 V/m)和均匀磁场(磁感应强度为B = 0.005 T)区域,求:(1) 光电子的最大速度v . (2) 单色紫外线的波长λ.(电子静止质量m e =9.11³10-31 kg ,普朗克常量h =6.63³10-34 J ²s)19. 若不考虑相对论效应,则波长为5500 Å的电子的动能是多少eV ?(普朗克常量h =6.63³10-34 J ²s ,电子静止质量m e =9.11³10-31 kg)20. 若光子的波长和电子的德布罗意波长λ相等,试求光子的质量与电子的质量之比.21. 以波长λ = 410 nm (1 nm = 10-9m)的单色光照射某一金属,产生的光电子的最大动能E K = 1.0 eV ,求能使该金属产生光电效应的单色光的最大波长是多少? (普朗克常量h =6.63³10-34 J ²s)1~5.DADDB 6~10.ADCBC11. λ/hc 1分λ/h 2分 )/(λc h 2分12. 2.21³10-323分 13. 2 1分2³(2l +1) 2分2n 2 2分14. 6.63³10-26J 2分2.21³10-34 kg ²m/s 2分15.)(20νν-m h 3分16. 量子化定态假设 1分量子化跃迁的频率法则hE E k n kn /-=ν 2分角动量量子化假设π=2/nh L n =1,2,3,…… 2分17. 1.51 3分18. 解:(1) 当电子匀速直线地穿过互相垂直的电场和磁场区域时,电子所受静电力与洛仑兹力相等,即B e eE v = 2分==B E /v 106 m/s 1分(2) 根据爱因斯坦光电理论,则有2210//v e m hc hc +=λλ 2分∴)(211020hcm e λλλv +=2分=1.63³10-7 m = 163 nm 1分19. 解:非相对论动能221v e K m E =而v e m p =故有e K m p E 22=2分 又根据德布罗意关系有λ/h p =代入上式 1分则==)/(2122λe K m h E 4.98³10-6 eV 2分20. 解:光子动量:p r = m r c = h /λ① 2分电子动量:p e = m e v = h /λ② 2分两者波长相等,有m r c = m e v得到m r / m e =v / c ③电子质量22/1c v m m e -=④ 2分 式中m 0为电子的静止质量.由②、④两式解出)/(122220h c m cv λ+=2分代入③式得)/(1122220h c m m m e r λ+=2分21. 解:设能使该金属产生光电效应的单色光最大波长为λ0.由0=-A h ν可得)/(0=-A hc λA hc /0=λ 2分又按题意:K E A hc =-)/(λ∴K E hc A -=)/(λ得λλλλK K E hc hc E hc hc -=-=)/(0= 612 nm 3分相对论1. 宇宙飞船相对于地面以速度v 作匀速直线飞行,某一时刻飞船头部的宇航员向飞船尾部发出一个光讯号,经过∆t (飞船上的钟)时间后,被尾部的接收器收到,则由此可知飞船的固有长度为 (c 表示真空中光速) (A) c ²∆t (B) v ²∆t(C)2)/(1c tc v -⋅∆ (D) 2)/(1c t c v -⋅⋅∆[]2. 有下列几种说法:(1) 所有惯性系对物理基本规律都是等价的.(2) 在真空中,光的速度与光的频率、光源的运动状态无关.(3) 在任何惯性系中,光在真空中沿任何方向的传播速率都相同. 若问其中哪些说法是正确的, 答案是 (A) 只有(1)、(2)是正确的. (B) 只有(1)、(3)是正确的. (C) 只有(2)、(3)是正确的.(D) 三种说法都是正确的.[] 3. 在某地发生两件事,静止位于该地的甲测得时间间隔为4 s ,若相对于甲作匀速直线运动的乙测得时间间隔为5 s ,则乙相对于甲的运动速度是(c 表示真空中光速) (A) (4/5) c . (B) (3/5) c .(C) (2/5) c . (D) (1/5) c .[] 4. 某核电站年发电量为 100亿度,它等于36³1015 J 的能量,如果这是由核材料的全部静止能转化产生的,则需要消耗的核材料的质量为 (A) 0.4 kg . (B) 0.8 kg .(C) (1/12)³107 kg . (D) 12³107 kg .[]5. 一个电子运动速度v = 0.99c ,它的动能是:(电子的静止能量为0.51 MeV)(A) 4.0MeV . (B) 3.5 MeV .(C) 3.1 MeV . (D) 2.5 MeV .[]6.狭义相对论中,一质点的质量m 与速度v 的关系式为______________;其动能的表达式为______________.7. 质子在加速器中被加速,当其动能为静止能量的3倍时,其质量为静止质量的________倍.8.狭义相对论的两条基本原理中,相对性原理说的是_________________ ____ ___________________________________________________________;光速不变原理说的是_______________________________________________ ___________________________________________.9. π+介子是不稳定的粒子,在它自己的参照系中测得平均寿命是2.6³10-8s,如果它相对于实验室以0.8 c (c为真空中光速)的速率运动,那么实验室坐标系中测得的π+介子的寿命是______________________s.10. 一艘宇宙飞船的船身固有长度为L0=90 m,相对于地面以=v0.8 c (c为真空中光速)的匀速度在地面观测站的上空飞过.(1) 观测站测得飞船的船身通过观测站的时间间隔是多少?(2) 宇航员测得船身通过观测站的时间间隔是多少?11. 假定在实验室中测得静止在实验室中的μ+子(不稳定的粒子)的寿命为 2.2³10-6 m,而当它相对于实验室运动时实验室中测得它的寿命为1.63³10-6s.试问:这两个测量结果符合相对论的什么结论?μ+子相对于实验室的速度是真空中光速c的多少倍?12.一隧道长为L,宽为d,高为h,拱顶为半圆,如图.设想一列车以极高的速度v沿隧道长度方向通过隧道,若从列车上观测,(1) 隧道的尺寸如何?(2) 设列车的长度为l0,它全部通过隧道的时间是多少?1-5. ADBAC6.20)/(1c m m v -=2分202c m mc E K -= 2分7. 4 3分8. 一切彼此相对作匀速直线运动的惯性系对于物理学定律都是等价的 2分一切惯性系中,真空中的光速都是相等的 2分 9. 4.33³10-83分 10. 解:(1) 观测站测得飞船船身的长度为=-=20)/(1c L L v 54 m则 ∆t 1 = L /v =2.25³10-7 s 3分(2) 宇航员测得飞船船身的长度为L 0,则∆t 2 = L 0/v =3.75³10-7s 2分11. 解:它符合相对论的时间膨胀(或运动时钟变慢)的结论 2分设μ+子相对于实验室的速度为vμ+子的固有寿命τ0 =2.2³10-6 s μ+子相对实验室作匀速运动时的寿命τ0 =1.63³10-5 s按时间膨胀公式:20)/(1/c v -=ττ移项整理得:202)/(τττ-=c v 20)/(1ττ-=c = 0.99c 3分12. 解:(1) 从列车上观察,隧道的长度缩短,其它尺寸均不变。
2016考研真题及答案解析
2016考研真题及答案解析全程报道2016考研试卷及答案公布(点击进入考研真题解析专题),新东方网考研频道时刻关注2016考研初试情况,第一时间为考生提供考研真题答案及答案解析内容,同时新东方考研名师将在考后为考生提供在线答案解析直播。
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一、A型题:1~90小题,每小题i.s分;gl~120小题,每小题2分;共1 95分。
在每给出的A, B, C,D 四个选项中,请选出一项最符合题目要求的。
1.下列关于机体内环境稳态的描述,错误的是DA.稳态是一种动态平衡B.稳态的维持是机体自我调节的结果c.稳态调节中都有一个调节点D.稳态是指细胞内液理化性质基本恒定2.在引起和维持细胞内外Na+、K+不对等分布中起重要作用的膜蛋白是BA.载体B.离子泵c.膜受体D.通道3.神经细胞的静息电位为一70mV, Na+平衡电位为+60mV, Na+的电化学驱动力则为AA. -130mVB. -10mVC. +lOmVD. +130mV4.风湿热时,红细胞沉降率加快的原因是CA.红细胞表面积/体积比增大B.血浆白蛋白、卵磷脂含量增高C.血浆纤维蛋白原、球蛋白含量增高D.红细胞本身发生病变5.阿司匹林通过减少TXA2合成而抗血小板聚集的作用环节是AA. 抑制COXB.抑制TXA-,合成酶C.抑制PGI7合成酶D.抑制PLA26.心室肌细胞在相对不应期和超常期内产生动作电位的特点是BA.0期去极化速度快B.动作电位时程短C.兴奋传导速度快D.O期去极化幅度大7。
在微循环中,进行物质交换的血液不流经的血管是BA.后微动脉B.通血毛细血管C.微静脉D.微动脉8.下列呼吸系统疾病中,主要表现为呼气困难的是AA.肺气肿B.肺水肿C.肺纤维化D.肺炎9.下列关于CO影响血氧运输的叙述,错谈的是AA. CO中毒时血02分压下降B. CO妨碍02与Hb的结合C. CO妨碍02与Hb的解离D.cO中毒时血02含量下降10.下列关于颈动脉体化学感受器的描述,错误的是DA.其流入流出血液中的Pa02差接近零,通常处于动脉血环境中B. Pa02降低、PaC02和H+浓度升高对其刺激有协同作用c.感受器细胞上存在对02,、C02、H+敏感的不同受体D.血供非常丰富,单位时间内血流量为全身之冠11.胃和小肠蠕动频率的决定性因素是DA. 胃肠平滑肌动作电位频率B.胃肠平滑肌本身节律活动C. 胃肠肌问神经丛活动水平D.胃肠平滑肌慢波节律12.在胃黏膜壁细胞完全缺乏时,病人不会出现的表现是CA.维生素B12吸收障碍B.肠道内细菌加速生长C.胰腺分泌HC03-减少D.食物蛋白质消化不良13.促进胰腺分泌消化酶最主要的胃肠激素是CA.胰多肽B.促胰液素C.缩胆囊素D.胃泌素14.人体发热初期出现畏寒、寒战的原因是BA.散热过程受阻B.体温调定点上调C.体温调节中枢功能异常D.产热过程过强15.利用肾清除率概念测定GFR,被清除物除能被肾小球滤过外,尚需满足的条件是CA.不被肾小管重吸收,但可被分泌B.可被肾小管重吸收,但不可被分泌C.不被肾小管重吸收和分泌D.可被肾小管重吸收和分泌16.肾小管重吸收Na+与水的量与肾小球滤过率成定比关系的部位是DA.髓袢细段B.髓袢升支粗段C.远曲小管D.近端小管17.机体安静情况下,对醛固酮分泌调节不起作用的因素是CA.高血Na+B.血管紧张素IIC.促肾上腺皮质激素D.高血K+18.视网膜中央凹处视敏度极高的原因是DA.感光细胞直径小,感光系统聚合联系B. 感光细胞直径大,感光系统单线联系C.感光细胞直径大,感光系统聚合联系D.感光细胞直径小,感光系统单线联系19.在突触传递中,与神经末梢释放递质的数量呈正相关的因素是DA.末梢内囊泡的大小B.囊泡内递质的含量C.活化区面积的大小D.进入末梢的Ca2+量20.在周围神经系统中,属于胆碱能纤维的是CA.所有副交感节后纤维B.所有支配血管的交感节后纤维C.所有自主神经节前纤维D.所有支配汗腺的交感节后纤维21.下列激素中,能使机体的能量来源由糖代谢向脂肪代谢转移的是CA.胰岛素B.皮质醇C.生长激素D.甲状腺激素22.口服葡萄糖比静脉注射等量葡萄糖引起更多的胰岛素分泌,其原因是BA.小肠吸收葡萄糖非常完全。
大学物理(题库)含答案
06章一、填空题(一)易(基础题)1、热力学第二定律的微观实质可以理解为:在孤立系统内部所发生的不可逆过程,总是沿着熵 增大 的方向进行。
2、热力学第二定律的开尔文表述和克劳修斯表述是等价的,表明在自然界中与热现象有关的实际宏观过程都是不可逆的,开尔文表述指出了____功热转换__________的过程是不可逆的,而克劳修斯表述指出了___热传导_______的过程是不可逆的.3.一定量的某种理想气体在某个热力学过程中,外界对系统做功240J ,气体向外界放热620J ,则气体的内能 减少 (填增加或减少),E 2—E 1= -380 J 。
4.一定量的理想气体在等温膨胀过程中,内能 不变 ,吸收的热量全部用于对外界做功 。
5.一定量的某种理想气体在某个热力学过程中,对外做功120J ,气体的内能增量为280J ,则气体从外界吸收热量为 400 J 。
6、在孤立系统内部所发生的过程,总是由热力学概率 小 的宏观状态向热力学概率 大 的宏观状态进行。
7、一定量的单原子分子理想气体在等温过程中,外界对它作功为200J.则该过程中需吸热____-200____J.补充1、一定量的双原子分子理想气体在等温过程中,外界对它作功为200J.则该过程中需吸热____-200____J.补充2、一定量的理想气体在等温膨胀过程中,吸收的热量为500J 。
理想气体做功为 500 J 。
补充3、一定量的理想气体在等温压缩过程中,放出的热量为300J ,理想气体做功为 -300 J 。
8、要使一热力学系统的内能增加,可以通过 做功 或 热传递 两种方式,或者两种方式兼用来完成。
9、一定量的气体由热源吸收热量526610J ⋅⨯,内能增加541810J ⋅⨯,则气体对外作 功______J.10、工作在7℃和27℃之间的卡诺致冷机的致冷系数为 14 ,工作 在7℃和27℃之间的卡诺热机的循环效率为 6.67% 。
(二)中(一般综合题)1、2mol 单原子分子理想气体,经一等容过程后,温度从200K 上升到500K,则气体吸收的热量为_37.4810⨯____J.2、气体经历如图2所示的一个循环过程,在这个循环中,外界传给气体的净热量是 90J 。
大学物理考研试卷
大学物理模拟试卷二一、填空题Ⅰ(30分,每空2分)1.己知一质点的运动方程为[]r (5sin 2)(4cos2)t i t j ππ=+(单位为米),则该质点在0.25s 末的位置是________,从0.25s 末到1s 末的位移是________【考查重点】:这是第一章中的考点,考查运动物体的位移,要注意的是位移是矢量,要知道位移和路程的区别【答案解析】质点在0.25s 末的位置为: 质点在1s 末的位置为: 这段时间内的位移为:10.25r r(54)r i j m ∆=-=-+2.一质量为m 的质点在指向圆心的平方反比力2/F k r =-的作用下,作半径为r 的圆周运动.此质点的速度v=____.若取距圆心无穷远处为势能零点,它的机械能E=_______【考查重点】:这是第二章中的考点,考察匀速圆周运动的速度问题,要注意的是机械能等于动能加上势能,势能中注意选取势能零点【答案解析】:22mv kv r r =⇒=3.一轻绳绕于r=0.2m 的飞轮边缘,以恒力F=98N 拉绳,如图所示。
已知飞轮的转动惯量?J=20.5g K m ⋅,轴承无摩擦。
则飞轮的角加速度为_______;绳子拉下5m 时,飞轮的角速度为_______,动能为_______【考查重点】:这是第三章中的考点,考察的是刚体动力学中物理运动的相关参量,要记得公式,并注意区别参量之间的区别 【答案解析】:由转动定理得: 由定轴转动刚体的动能定理得:4.已知一平面简谐波沿x 轴负向传播,振动周期T=0.5s,波长?=10m,振幅A=0.1 m.当t=0时波源振动的位移恰好为正的最大值.若波源处为原点,则沿波传播方向距离波源为?/2处的振动方程为y=______;当t=T/2时,x=?/4处质点的振动速度为______ 【考查重点】:这是第四章中的考点,考察的是平面简谐波的运动方程【答案解析】:0.5s T=24Tπωπ== 沿x 轴负向传播,且t=0时波源振动的位移恰好为正的最大值,则该简谐波的波动方程为:沿波传播方向距离波源为?/2处,x=-?/2,则振动方程为:x=?/4处质点的振动方程为:)4cos(1.0ππ-=t y )24cos(1.0ππ+=t y求导得速度方程为:0.4sin(4)2V t πππ=+当t=T/2时,速度为:30.4sin 1.26m/s 2V ππ==-5.一弹簧振子作简谐振动,其振动曲线如图所示。