西尔斯当代大学物理双语PPT课件
西尔斯大学物理Ch4-1 Work and Energy-2
3
University Physics
Chapter Outline
§4-1 Kinetic Energy and Work
§4-2 Calculating the Work
§4-3 Path Independence of Conservative Forces
f f
f
f
W i F dl i Fxdx i Fydy i Fzdz
11
University Physics
§4-1 Kinetic Energy and Work
Example 4-1 A particle moves alorng arpararbolic path x2= 4y. The force acting on it is F 2 yi 4 j (N). How much work is done on the particle as it moves from x = 2 m to x = 3 m?
condition vA = 0
mgl sin
1 2
mvB2
vB
2gl sin
19
University Physics
§4-2 Calculating the Work
20
University Physics
§4-2 Calculating the Work
In Cartesian coordinate system:
➢ Work is energy transferred to or from an object by means of a force acting on the object.
大学物理课件英文版课件,现代物理An Aperitif of Modern Physics
3
§26.1 Some important discoveries at the end of the 20th century
2. The discovery of X-rays
§26.1 Some important discoveries at the end of the 20th century
J. J. Thomson’s original tube
2
§26.1 Some important discoveries at the end of the 20th century
a. Measured the charge of the cathode rays; b. Make a static electric deflection of the cathode rays; c. Measured the charge to mass ratio of the cathode rays; d. Prove the universal existence of the electron. The charge to mass ratio of electron
Radioactivity occur naturally and have with us on the earth from the very beginning. Henri Becquerel discovered Uranium, Marie Curie discovered Polonium and Radium Ernest Rutherford found that the substances emit several distinct types of radiations. One is a penetrating radiation, dubbed α, that propagates through several centimeters in air and can even penetrate very thin metal foils. Another less penetrating radiation, dubbed β, is easily stopped by even a sheet of paper. Another type, called γ, was discovered in 1900 and is much more penetrating than even the α radiation.
西尔斯当代大学物理双语PPT课件
.
17
轶事:蜘蛛织网和平面直角坐标系的创立
• 据说有一天，笛卡尔生病卧床，病情很重，尽管如 此他还反复思考一个问题：几何图形是直观的，而代数 方程是比较抽象的，能不能把几何图形和代数方程结合 起来？他苦苦思索，拼命琢磨，通过什么样的方法，才 能把“点”和“数”联系起来。突然，他看见屋顶角上 的一只蜘蛛，拉着丝垂了下来。一会功夫，蜘蛛又顺这 丝爬上去，在上边左右拉丝。蜘蛛的“表演”使笛卡尔 的思路豁然开朗。他想，可以把蜘蛛看作一个点。他在 屋子里可以上、下、左、右运动，能不能把蜘蛛的每一 个位置用一组数确定下来呢？他又想，屋子里相邻的两 面墙与地面交出了三条线，如果把地面上的墙角作为起 点，把交出来的三条线作为三根数轴，那么空间中任意 一点的位置就可以在这三根数轴上找到有顺序的三个数。 反过来，任意给一组三个有顺序的数也可以在空间中找 到一点P与之对应，这就是坐标系的雏形。
by describing how to calculate it from other quantities that we can measure.
speed = distance / time
v = d / t (m/s)
An equation must always be dimensionally consistent.
位移
average velocity
平均速度
instantaneous velocity
瞬时速度
acceleration
加速度
confusion
混淆
rectilinear motion
直线运动
.
20
valid
正确的
大学物理英文版PPT
4.Units 单位
International System of Units SI: Syst me International d’Unit s 法语 is used in China
mass
m
kg:千克 kilogram
length
L m:米 meter
Time
t s:秒 second
5. Scalar and vector 标量和矢量 : Two types of physical quantities 量 :
主要讲授内容：
经典力学 相对论
电磁学
振动与波动 日常生活
波动光学
热学
量子论简介
puter 计算机科学
Medicine 医学
Physics
Chemistry 化学
Mechanics 机械学
Biology 生物学
Physics: fundamentals and methods.
References 参考书
主要贡献： •发明了望远镜,维护、坚持和发展了哥白尼学说, 发现木星的四个卫星； •摆的等时性、惯性定律、落体运动定律； •运动的合成原理和独立性原理,相对性原理； •方法：实验科学。
§1-1 Frame of Reference Particle 质点
1. Frame of Reference 参照系
C=A+B B
A
B C
A
In Cartesi an coordinate system 直角坐标系 :
A A xiA yjA zk
i,jankd are unit vectors along OX,OY,OZ Y
O
X
Z
西尔斯当代大学物理课件1
Department of Electronic Engineering
运算： 运算： 1 加法： 加法：
A+ B
A+ B
A
B
2 减法： 减法：
A− B
A− B
A
B
Chapter1 Units, Physical Quantities and Vectors
10
Department of Electronic Engineering
如：力，速度，加速度，电流密度 等。 速度，加速度，
表示方式： 表示方式： 大小： 大小：
A
几何上用有方向的线段表示。 几何上用有方向的线段表示。
A = A
A
与
A
大小相等，方向相反。 − A 大小相等，方向相反。
9
Chapter1 Units, Physical Quantities and Vectors
1-9 Components of Vectors
利用直角坐标系， 利用直角坐标系，矢量可用其在坐标轴上的 投影/分矢量 分矢量（ 投影 分矢量（component vector）表示。 ）表示。
y
A = Ax + A y
A= A + A
2 x 2 y
A
Ay
θ
tgθ = Ay / Ax
Ax
x
Chapter1 Units, Physical Quantities and Vectors
1-1 Introduction
本章作为预备知识主要介绍: 本章作为预备知识主要介绍 1. 理想模型 (idealized models) 2. 物理量单位制 (systems of Units) 3. 精度与有效数字 (significant figures) 4. 矢量与矢量代数
《物理双语教学课件》Chapter 19 Magnetic Field 磁场
Chapter 19 Magnetic FieldWe have discussed how a charged plastic rod produces a vector field-the electric field E -at all points in the space around it. Similarly, a magnet produces a vector field-the magnetic field B -at all points in the space around it.19.1 The Definition of B1. We determined the electric fieldE at a point by putting a test particle of charge q at rest at that point and measuring the electric forceE F acting on the particle. We then defined E as q F E E =.2. To define the magnetic fieldB , we can fire a charged particle through the point whereB is to be defined, using various directions and speeds for the particle and determining the force B F that acts on the particle at that point.(1) After many such trials we would find that when theparticle ’s velocity v is along a particular axis through thepoint, force B F is zero .(2) For all other directions ofv , the magnitude of B F is always proportional to φsin v , where φ is the angle betweenthe zero-force axis and the direction of v .(3) Furthermore, the direction B F is always perpendicular tothe direction of v (These results suggest that a cross productis involved).3. We can then define a magnetic fieldB to be a vector quantity that is directed along the zero-force axis . We can next measure the magnitude of B F when v is directed perpendicular tothat axis and then define the magnitude ofB in terms of that force magnitude: vq F B B =, where q is the charge of the particle. 4. We can summarize all these results with the following vector equation: B v q F B ⨯=.5. Finding the magnetic force on a particle: The forceB F acting on a charged particle moving with velocityv through a magnetic field B is always perpendicular tov and B . 6. The SI unit for B is the netown per coulomb-meter persecond. For convenience, that is called the tesla (T). An earlier (non-SI) unit for B , still in common use, is the gauss (G), and 1 tesla = 104 gauss.7. Right table lists themagnetic fields thatoccur in a fewsituations.8. We can represent magnetic fields with field lines , just as wedid for electric field. Similar rules apply. That is, (1) the direction of the tangent to a magnetic field line at any point gives the direction B at that point, and (2) the spacing of the lines represents the magnitude of B -the magnetic field is stronger where the lines are closer together, and conversely. 9.Figures show the magnetic field lines for magnet with different shapes. We find that the lines all pass through the magnet, and they form closed loops(even those that are notshown closed in the figures). The closed field lines enter one end of a magnet and exit the other end. The end of a magnet from which the field lines emerge is called the north pole of the magnet; the other end, where field lines enter the magnet, is called the south pole.10.W hen two magnets are moved to each other, we find that opposite magnetic pole attract each other, and like magnetic pole repel each other.11.E arth has a magnetic field that is produced in its core by stillunknown mechanisms.19.2 Crossed FieldBoth an electric field E and a magnetic field B can produce a force on a charged particle. When the two fields are perpendicular to each other, they are said to be crossed fields. 1.Discovery of the electron: Figure shows a modern version of J.J. Thomson’s apparatus for measuring the ratio of mass to charge for the electron.2.The Hall effect: Halleffect allows us to findout whether the chargecarriers in a conductoror semiconductor arepositively ornegatively charged.Beyond that, we can measure the number of such carriers perunit volume.(1) Figure shows a strip of copper carrying a current i is immersed in a magnetic field.(2) A hall potential difference is the difference of the electric filed potential between to edges of the strip. The magnitude of that potential difference is Ed V =.(3) When the electric and magnetic force are in balance , we have B ev eE d =, in which the drift speed of electrons is neA i v d =, in which n is the number density of charge carries.(4) From above three equations, we haveVleBi n =, in which l (=A/d) is the thickness of the strip.19.3 A Circulating Charged Particle1. If a particle moves in a circle at constant speed, we can be sure that the net force acting on the particle is constant in magnitude and points toward the center of the circle, always perpendicular to the particle ’svelocity.2. Figure shows that a beam ofelectrons is projected into achamber by an electron gun G .The electrons enter in theplane of the page with velocity v and move in a region ofuniform magnetic field B directed out of the plane of thefigure. As a result, a magnetic force continually deflects the electrons, and because v and B are perpendicular to eachother, this deflection causes the electrons to follow a circular path.3. From Newton ’s law applied to uniform circular motion, we have rmv qvB 2=. (1) So the radius of the circular path is qBmv r =. (2) The period (the time for one full revolution) is equal to the circumferencedivided by the speed:qBm v r T ππ22==. (3) The frequency is mqB T f π21==. (4) The angular frequency of themotion is then mqB f ==πω2. (5) They are do not dependon the speed of the particle.4. Helical paths : If the velocityof a charged particle has acomponent parallel to the (uniform) magnetic field , theparticle will move in helical path about the direction of the field vector, as shown in figure (a) and (b). The parallel component of the velocity determines the pitch of the helix, that is, the distance between adjacent turn. The perpendicular component determines the radius of the helix.5.Figure (c) shows the charged particle spiraling in a non-uniform magnetic field. The more closely spaced field lines at the left and right sides indicate that the magnetic field is stronger there. When the field at end is strong enough, the particle “reflects”from that end. If the particle reflects from both ends, it is said to be trapped in a magnetic bottle. Electrons and protons are trapped in this way by the terrestrial magnetic field, forming the Van Alen radiation belts, which loop well above Earth’s atmosphere, between Earth’s north and south geomagnetic poles. The trapped particles bounce back and forth, from end to end of the magnetic bottle, within a few seconds.19.4 Cyclotrons and Synchrotrons1.The Cyclotron is a device forgiving high speed to chargedparticles by magnetic and electricfields. See the figure.2. The proton synchrotron:19.5 Magnetic Force on a Current-Carrying Wire1. See right figure, in which thecurrent-carrying wire is perpendicular tothe magnetic field, the magnetic force isiLB F B =.2. If the magnetic is not perpendicular tothe wire, as in right figure, themagnetic force is given byB L i F B ⨯=. Here L is a lengthvector that points along the wiresegment in the direction of the conventional current.3. If a wire is not straight , we can imagine it broken up into small straight segments and apply above equation to each segment. The force on the wire as a whole is then the vector sum of all the force on the segments that make it up. In the differential limit, we can write B L id F d B ⨯=, and we can find the resultant force on any given arrangement of currents by integrating it over that arrangement .19.6 Torque on a Current Loop and the Magnetic dipole1. Figure shows a simplemotor, consisting of asingle current-carryingloop immersed in a magnetic field B .2. The magnitude of the torque is θθτsin )(sin B iA iabB ==.3. We can describe the current-carrying coil with a single vector μ , its magnetic dipole moment , we take the direction of μ tobe that of the normal vector n to the plane of the coil, asfigure (c). We define the magnitude ofμ as NiA =μ, in which N is the loop of the coil; A is the area enclosed by the coil. Then the torque can be written as B⨯=μτ 4. While an external magnetic field is exerting a torque on a magnetic dipole, work must be done to change the orientation of the dipole. The magnetic dipole must then have a magneticpotential energy . We can write it as B U ⋅-=μθ)(.。
大学物理(双语)
v = v x2 + v y2
v and tanθ = v y x
r r r Ar B = C × r
r C
r B
α
Both pairs of values contain the same information.
Direction ( figure )
r A
2
�
?
Coordinate system can be chosen freely.
Components of vectors (50)
A component of a vector is the projection of the vector on an axis. This component may be in 2 or 3 dimensional (3D) coordinate system.
gh = 1 v 2 2
L T 2 L
L 2 T
[L T ] = [L T ]
2 2 2 2
一个量的量纲是该量所描述的物理特性
The dimensions on both sides of an equation must be equal. ----check the validity(正确性)of a calculation
Watt and Angstrom ( A ) are derived units.
Derived unites are defined in terms of the basic units. Some have given names, some do not.
speed force m/s kgm/s2 Newton
Scientific notation Mass of the Earth:
西尔斯物理学（Searsphysics）
西尔斯物理学（Sears physics）This article is contributed by yuanye668Ppt documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view.Sears physicsSears and Zemansky 's University PhysicsNew1. Commemorative: memorial.2. Rigorous: strict, harsh. WhatWords3. Testament: wills, legacy.4. Pitfall: defects. Pitfall:5. Plague:n. trouble, trouble. Vt. tormented and tortured.6. Prose: prose.7. Conversational:, conversational, talkative, conversational.8., colloquial: spoken, popular.9. Faculty: ability, faculty, faculty. 10. Comment: notes, comments, comments. 11. Hint: hints, hints, clues. 12. Paleontologist: paleontology with.13. Dinosaurs: dinosaurs. 14. Mousetrap: mouse. 15. Frustrating: frustrate; feel discouraged. 16. Insight: insight, insight. 17. Preliminary: prepared, preliminary. 18. Algebra: algebra. 19. Pattern: model, style, imitation. 20. Facility: easy, skilled, equipment, tools. 21. Pendulum: pendulum,pendulum bob. 22. Chandelier: tree shaped decorative lamp. 23. Cathedral: cathedral. 24. Ultraviolet: UV radiation. 25. Infrared: infrared. 26. Jupiter: jupiter. 27., Interplay: interact with each other. 28. Inconsistent: inconsistent; contradictory. 29. Cannonball: shells. 30., Validity: validity, validity, correctness.31. Strategy: strategy, strategy. 32. Absolutely:, complete, absolute. 33. Replica: copies. 34. Spherical: ball type 35. Thereof: in which, relating to... Put it, it's. 36. seam: wiring, suture, scar, layer. 37. Concentrate: concentrates, concentrates. 38., Fairly:, fairly, fairly, clearly. 39. Ruler: ruler. 40., Multiple:, multiple, multiple, multiple, several. Multiplied. 41. Gram: grams. 42. Exponential: index, advocates, index, exponential. 43. Prefix: prefix. 44. Abbreviated: short, abbreviated. 45. Nanometer: nm. 46. Nanosecond: ns. 47. Equivalent: quite. Equal. 48. "Denote:" indicating. 49. in Dimensionally: space, in magnitude, in magnitude. 50. Treated: treated as discussed.51., Multiplication: multiplication, increase, value-added.52. Division: division, division, allocation. 53. Glossary: terms. 54. Thumb: flip the page. 55. Cram: fill up. 56. Equator: equator. 57. Cumbersome: annoying, troublesome, bulky. 58. Porsche Porsche. 59. Cesium: cesium. 60. Bombard: excitation. Sixty-oneGlow: glow, heat. 62. Vacuum: vacuum. 63. Cylinder: cylinder.64. Platinum: platinum, platinum. 65. Iridium: iridium. 66. Alloy: alloy. 67. Prefix: prefix. 68., Consistency: combination, unity, consistency, consistency. Density.69., Conversion: conversion, conversion. 70. Dimensionally: in size or size. 71. "Denote:" indicating. 72. Figures: shape, body shape. Silhouette. Graphics, numbers. 73. Caliper: calipers, calipers, calipers, horns. 74. Error: error. 75. Fractional part of the shard. 76. Scalar. scalar. 77. Vector. vector. 78. Displacement. displacement. 79. Boldface. bold, boldface. 80. Italic. italic. 81. Segment. segments. 82. Magnitude. modulus.83. Anti-parallel. antiparallel. 84. Perpendicular.adj vertical, orthogonal. N perpendicular. 85. Root: n root; root mean square. 86., Mutually:, adv, help each other. 87. Drag: tardiness. 88. Racer: the match.89. Dragster: high speed racing car. 90. Interval: interval, distance, time interval. 91. Precisely: just right. 92. Instantaneous: instant, instant. 93. Instant: immediately; urgent. 94. Calculus: calculus. 95. Approaches: approach; approach. Derivation of 96. Derivative:; derivation. 97. Term: term; terminology. 98. Interchangeably: can alternate. 99. Distinct: clear and clear. 100. "Denote:" indicating.101.Cheetah: India leopard; 102. Crouch: curled, crouch. 103. Ambush: ambush. 104. Blind: blind or blind; disoriented. 105. Antelope: antelopes. 106. Slope: slope; slope. 107. Procedure: procedures; procedures. 108. Race: race; race. 109. Straightaway: straight track; straight line segment.110. Grand Prix: International Grand prix. 111. Catapult: aircraft catapult slingshot. 112. Versus: pairs, relative. 113. Arbitrary: arbitrary. 114. Signpost: roadmap. 115. Wustang: mustang. 116., Approach:, n approach, approach, approach, step, approach. Vt. approach. 117. Concave: adj: concave, concave.N: concave. 118. Label: n. tags, labels, signs. Vt. affixed to, refers to... For, classify. 119. Roller: n roller. 120. Coaster: offshore trade freighter. 121. Radial: adj, radial, ray, radius. Light ray. 122., Wrap, up:, V, disguise, disguise, concentrate, wrap, scarf, wrap up. 123., Neat:, adj., neat, smart, elegant, (wine), pure, not watered. 124. Net: n. network, network, net profit, net. Adj. net, pure. One hundred and twenty-fiveModification: no 更改, 修正. 126. Rope: no 绳索. 127. Tie: no 带子, 领带.vt. 系, 打结. 128. Exert: vt.尽力, 施加, 努力. v.发挥, 竭尽全力, 尽.129. Superposition: no 重叠, 重合, 叠合.合成. 130. Utmost: no 极限, 最大可能, 极力.adj. 极度的, 最远的. 131. Puck: no 恶作剧的小妖精; 冰球. 132. Sustain: 维持, 持续. 133. Ketchup: 调味番茄汁. 134. Contact force: 触点压力 135. Calibrate: v.校准. 136. Platinum: n.白金, 铂. 137. Iridium: no 铱. 138. Dimensionally: adv.尺寸上的.量纲. 139. Handled: adj.把手的.手柄的. 140. Pose: n.姿势, 姿态.v. (使) 摆好姿势, 形成, 因其, 造成. 141. Equilibrium: n.平衡, 平静. 142. Trivia: adj; 琐细的, 价值不高, 微不足道的. 143. Furthermore, adv.此外, 而且. 144. The cutting blade: 切割刀具. 145. Aligned: vi.排列.vt.使结盟, 使成一行. 146. Toboggan: n.平底雪橇.v. 乘撬滑下, 急剧滑下. 147. Iceboat: n.冰上滑行船, 碎冰船. 148. Analytical: adj: 分析的, 解析的.149. Hoisting: n.起重, 提升. 150.synonym: n.同义词.151.normal force: 法向力. 152.slippery: adj. 滑的, 光滑的. 153. Quotient: n.商, 份额. 154. Stick: n.棍, 棒, 手杖.v. 粘住, 粘贴.vt.刺, 戳. 155.horrible: adj.可怕的, 恐怖的, 讨厌的. 156.squeak: n.尖叫声, 吱吱声, 机会.v.发出尖叫声. 157.chalk:n.粉笔. 158.windshield-wiper: 风挡刮雨器. 159.weld: vt.焊接.焊接, 焊缝. 160.toss: v.投掷. 161.drag: v.拖, 拖曳, 缓慢而费力地行动.n.拖拉. 162. Buoyancy: no 浮力, 浮性, 轻快. 163. Terminal: n.终点, 终端.adj. 期末, 末端的. 164. Subatomic: adj.小于原子的; 亚原子的, 次原子的. 165. Unaided: adj. 未受协助的, 独立的 166. Comb: no 梳子, 鸡冠, 蜂巢.vi.梳发, 搜索. 167. Fluff: n.软毛.柔毛, 绒毛, 错误, 无价值的东西.vi. 起毛的. 168. Repulsion: n.推斥, 排斥, 严拒, 厌恶, 反驳.169. Counteract: vt.抵消, 中和, 阻碍. 170. Vital: adj.生死攸关的, 重大的, 生命的, 生机的, 至关重要的. 171. Radioactivity; n.放射能. 172. Beta decay: no β衰变. 173. Antineutrino: n.反中微子. 174. Tremendous: adj. 极大的. 175. Concentration: n.集中, 集合, 专心, 浓缩, 浓度. 176. Stall: no 货摊Corral, stables; V. (to) stop, stop, delay (make). 177. Theorem: theory, theorem. 178. Throttle: kills the brakes. 179. Brake:n. brake. V. brake. 180., Segment:, N. segment, section, fragment. V. segmentation. 181. Rectangle: n. rectangle, rectangle. 182. Elongation: n. extension. 183., Floppy:, adj., soft, lazy. 184. Toy: n. toys. 185., Slinky:, adj., furtive, figure, curve. 186., Stiffer:, adj., stiff, stiff, stiff. 187. Suspension: n. suspension, suspension, suspension, suspension, suspension, 188., Triangle:, N., triangle, three person group.189. Individual: n. individuals, individuals. Adj. individual, individual, individual. 190., Infinitesimal:, adj., infinitesimal, infinitesimal, infinitesimal, N., infinitesimal, infinitesimal. 191., Rigorously:, adj., stern, cruel. 192., Evaluate:, vt., evaluation, valuation, etc... Value; V. evaluation. 193. Obnoxious: adj. unpleasant orunpleasant. 194., Swing:, v., rocking, swinging, turning, spinning; n. swings, swings, swings. 195., Quotient:, N. quotient, share. 196., Deposit:, N. deposits, deposits, deposits, deposits, deposits, vt. deposits, deposits; VI. deposits. 197. Hammerhead: n. adj. hammer; hammerhead, hebetic. 198., Momentarily:, adv., right now. 199., Slant:, v., oblique, oblique; n. inclined. 200. Elongation: n. extension. 201., Coil:, v., coil, roll. 202. Bounce: v. n. jump, jump, bounce back. 203., Suspension:, N. suspension, suspension, suspension, suspension, delay. 204. Flex: vt. bending, stretching, bending; n. VI bending, bending, wire, elastic band. 205. Strategy: n. policy. 206. Wrinkle: n. wrinkles; V. wrinkles.More resources, First day, English first day, math first, politics first, history first, geography firstOne。
大学物理英文版PPT
Elastic mechanics
When a force is applied to an object, it may under deformation If the force is removed, the object returns to its original shape and size, the deformation is said to be elastic
Polarization refers to the direction of these movements within the plane perpendicular to the direction of promotion
Polarization is a property of electrical waves and is observed in both natural and artistic sources of light
Angular Momentum
Angular Momentum is the rotational equivalent of linear momentum It is defined as the product of an object's mass and its angular velocity, and it is conserved in closed systems
要点一
要点二
Magnetic induction intensity
The magnetic induction intensity or magnetic field strength is the magnet of the magnetic field at a given point in space
西尔斯大学物理
Parallel Resistors I
1) 10 A
2) zero 3) 5 A
ቤተ መጻሕፍቲ ባይዱ
4) 2 A
5) 7 A
R2 = 2 W R1 = 5 W
10 V
ConcepTest 26.2a
In the circuit below, what is the current through R1?
Parallel Resistors I
connected across the
bulb, what happens?
ConcepTest 26.3a
Current flows through a lightbulb. If a wire is now
Short Circuit I
1) all the current continues to flow through the bulb 2) half the current flows through the wire, the other half continues through the bulb 3) all the current flows through the wire 4) none of the above
Short Circuit II
1) glow brighter than before 2) glow just the same as before 3) glow dimmer than before 4) go out completely 5) explode
ConcepTest 26.3b
Circuits II
1) twice as much
2) the same 3) 1/2 as much 4) 1/4 as much 5) 4 times as much
西尔斯当代大学物理双语课件
1.2 Idealized Models
We neglect the size and shape of the ball by representing it as a point object, or particle. We neglect air resistance by making the ball move in a vacuum. point We ignore the earth’s rotation. We make the weight constant.
Chapter 1 Physical Quantities and Vectors
1.1 The nature of physics
• Physics is an experimental science. • Physicists observe the phenomena of nature and try to find patterns and principles that relate these phenomena. These patterns are called physical theories or physical laws, or principles. • Every physical theory has a range of validity. • No theory has ever regarded as the final truth.
Unit prefixes: kilo-, centi-, milli-, micro-, nano
1.3 Standards and Units
Operational definition: kilogram meter second Derived unit: In other cases we define a physical quantity by describing how to calculate it from other quantities that we can measure. speed = distance / time
大学物理西尔斯
§28.4 the nuclear atom
1 . Two important models for atoms:
1) Thomson model：raisins-cake model
1903: J.J. Thomson The positive charges and the mass of the atom distribute uniformly in a sphere with the radius 10-10 m, and the electrons are immersed in the sphere.
1 1 ~ R( 2 2 ) 4 n
n 5,6,7,
Pfund series:
1 1 ~ R( 2 2 ) 5 n
n 6,7,8,
Similar regularity has been found in the spectra of atoms of other elements.
玻尔（Niels henrik David Bohr，1885-1962）
丹麦理论物理学家，现代物理学的创始人之一。 在1913年发表了《论原子结构与分子结构》等三 篇论文，提出了在卢瑟福原子有核模型基础上的 关于原子稳定性和量子跃迁的三条假设，从而圆 满地解释了氢原子的光谱规律。 玻尔的成功，使量子理论取得重大发展，推动了 量子物理的形成，具有划时代的意义。 玻尔于1922年12月10日诺贝尔诞生100周年之际， 在瑞典首都接受了当年的诺贝尔物理学奖金。 1937年，他来中国作学术访问，表达了对中国人 民的友好情谊。
Atomic Spectra of Hydrogen Lyman series:
UV
1 1 ~ R( 2 2 ) 1 n
《大学物理》英文课件18 Temperature, Heat, and The First Law of Thermodynamics(示)
Mechanics Newton’s 3 Laws r,v,a,F
Temperature
Kelvin scale; Has lower limit = absolute zero = 10-∞; no upper limit
The Zeroth Law of Thermodynamics
《大学物理》英文课件18 Temperature, Heat, and The First Law
of Thermodynamics(示)
Thermodynamics
Thermodynamics: The study of internal energy (thermal energy)
Thermodynamic Laws
Q 2LFm23 .8k 9J
Step 3: 0 oC (liq) →15 oC (liq)
Q 3cwm a(tT efr T i)4.2 5k 5J
Q to tQ 1Q 2Q 33k 0J 0
Sample Problem
Problem: A piece of copper with mass 75 g is heated to 312 0C. The copper is then dropped into a glass beaker containing 220 g water. The heat capacity Cb of the beaker is 45 cal/K .The initial temperature of the water and the beaker is 12 0C. Assuming that there is no energy loss, find the finial temperature of the system.
西尔斯当代大学物理英文版课程设计
2.Kinematics
3.Forces and Newton’s Laws
4.Work, Energy, and Power
5.Momentum and Collisions
6.Rotational Motion
7.Oscillations and Waves
•Introduce students to modern physics concepts
•Develop students’ quantitative skills and mathematical abilities
•Encourage students to apply physics principles to real-world problems
西尔斯当代大学物理英文版课程设计
IntroduБайду номын сангаасtion
The course of contemporary university physics is designed to provide students with a solid understanding of the fundamental principles of physics. This course is designed for undergraduate students and covers a broad spectrum of topics ranging from mechanics to quantum physics.
Each module includes lectures, problem-solving sessions, and laboratory exercises to help students apply physics concepts to real-world problems.
chap19(西尔斯当代大学物理)
(2) the goals of PBL
equal knowledge in physics.
building a suitable environment to promote
students conversion: from English learners into English users.
VH＝
+
B
+
+ f
+
vd
EH
nel
I
RH
l –
B
–
vd
f
–
–
EH
I
+ + + 2).measurement of the number of carriers per unit volume of conductor.
–
–
–
BI n＝ VH el
3).measurement of B,I,T
(half a million of words ) original English material in two semesters. about 20 min/page at least in average. 180h will be spent in reading the paragraphs my lecture will cover. English is a worry for most learners in China . physics is a difficult subject for most students. ambitious、self-confidence are needed.
Chap23 Electromagnetic waves
chap20 (2)(西尔斯当代大学物理)
dl
L
r
l
0 i d l sin B d B 2 L L 4 r
Calculate B：
O
R
I
P
18
dB
express dl , r 2 , sin in a single variable: From geometrical relation:
R R sin cos r cos sin
0, sin 0 B 0
2. At points lying in the plane perpendicular to v :
2
, sin 1 B Bmax
Note:
1. Direction of B : right-hand rule
2. permeability constant:
0 idl sin dB 2 4 r
0 Idl r 0 id l r dB 2 3 4 r 4 r
magnitude expression:
dB
idl
r
0 idl sin dB 2 4 r
: (idl , r )
direction of dB: right-hand rule
0 4 10 N A
7 2
1.26 10 T m / A
6
3. k
1 4 0
107 N S 2 C 2 c 2
1 0 0 2 c
Example:
Two protons move parallel to the x-axis in opposite direction at the same speed v (v<c) .At the instant shown ,find the electric and magnetic field forces on the upper proton and determine the ratio of their magnitudes.
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.
10
1.6 Vector Algebra
a Vector quantity can be expressed by a
• Every physical theory has a range of validity. • No theory has ever regarded as the final truth.
1.2 Idealized Models A model is a simplified version of a physical
Chapter 1 Physical Quantities
and Vectors
.
1
1.1 The nature of physics
• Physics is an experimental science. • Physicists observe the phenomena of nature and try to find patterns and principles that relate these phenomena. These patterns are called physical theories or physical laws, or principles.
ball move in a vacuum.
We ignore the earth’s rotation.
point masses
We make the weight constant.
.
5
1.3 Standards and Units
Physics is an experimental science. Experiments require measurements.
The system of units used around the world is called
Time S
Length m
Mass kg
Unit prefixes: kilo-,
centi-, milli-, micro-, nano
.
7
1.3 Standards and Units
Operational definition: kilogram meter second Derived unit: In other cases we define a physical quantity
by describing how to calculate it from other quantities that we can measure.
speed = distance / time
v = d / t (m/s)
An equation must always be dimensionally consistent.
Is it spherical ? It moves or spins ?
Wind Air resistance
The ball’s weight varies a little as its distance from the center of the earth changes
raised seam
time, temperature, mass, density, electric charge
But many other important quantities have a direction associated with them —— Vector quantity
A F a Vector quantity has both a magnitude and a direction
Mass —— balance —— kilogram
Distance —— ruler —— meter
Time interval —— stopwatch —— second
.
6
1.3 Standards and Units
International System (SI)
To make accurate, reliable measurements, we need units of measurement that do not change and that can be duplicated by observers in various locations.
Appendix A
.
8
1.4 Uncertainty and Significant Figures
.
9
1.5 Vectors and Scalars
Some physical quantities can be described completely by a single number with a unit —— Scalar quantity.
How complicated?
.4Leabharlann 1.2 Idealized Models
We neglect the size and shape of the ball
by representing it as a point object, or
particle.
We neglect air resistance by making the
system that would be too complicated to analyze in full detail.
point masses rigid bodies idealized insulators …… ……
.
3
1.2 Idealized Models
For Example: A baseball thrown through the air
Physical quantity
Number + Unit
Operational definition: Some physical quantities are so fundamental that we can define them only by describing how to measure them.