AP 物理C模拟题
2018ap物理c力学大题
2018ap物理c力学大题
2018年AP物理C力学大题主要涉及以下几个方面：
1. 力学基本概念，题目可能涉及牛顿运动定律、摩擦力、弹簧力、重力等基本力学概念。
学生需要理解这些概念并能够运用它们
解决问题。
2. 动量和能量，题目可能涉及动量守恒定律、动能、势能、机
械能守恒等内容。
学生需要能够分析物体的动能和势能变化，并理
解动量守恒的应用。
3. 旋转运动，题目可能涉及刚体的平衡、转动惯量、角动量等
内容。
学生需要理解刚体平衡的条件，能够计算刚体的转动惯量并
应用相关知识解决问题。
4. 振动和波动，题目可能涉及弹簧振子、简谐振动、波速、波
长等内容。
学生需要理解振动的特点、波动的传播规律，并能够运
用相关公式解决问题。
总体来说，2018年AP物理C力学大题涵盖了力学的基本概念、
动量和能量、旋转运动、振动和波动等多个方面的内容。
学生在备考时需要扎实掌握这些知识点，并能够灵活运用到解决实际问题的能力。
希望这些信息能够对你有所帮助。
【AP物理C】【真题】解答题答案C1989.pdf
AP® Physics C1989 Scoring GuidelinesThe materials included in these files are intended for use by AP teachers for course and exam preparation in the classroom; permission for any other use must be sought from the Advanced Placement Program®. Teachers may reproduce them, inwhole or in part, in limited quantities, for face-to-face teaching purposes but maynot mass distribute the materials, electronically or otherwise. These materials andany copies made of them may not be resold, and the copyright notices must beretained as they appear here. This permission does not apply to any third-partycopyrights contained herein.These materials were produced by Educational Testing Service® (ETS®), which develops and administers the examinations of the Advanced Placement Program for the College Board. The College Board and Educational Testing Service (ETS) are dedicated to the principle of equal opportunity, and theirprograms, services, and employment policies are guided by that principle.The College Board is a national nonprofit membership association dedicated to preparing, inspiring, and connecting students to college and opportunity.Founded in 1900, the association is composed of more than 4,200 schools, colleges, universities, and other educational organizations. Each year, theCollege Board serves over three million students and their parents, 22,000 high schools, and 3,500 colleges, through major programs and services incollege admission, guidance, assessment, financial aid, enrollment, and teaching and learning. Among its best-known programs are the SAT®, the PSAT/NMSQT®, and the Advanced Placement Program® (AP®). The College Board is committed to the principles of equity andexcellence, and that commitment is embodied in all of its programs, services, activities, and concerns.Copyright © 2002 by College Entrance Examination Board. All rights reserved. College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board. APIEL is a trademark owned by the College Entrance Examination Board. PSAT/NMSQT is a registered trademark jointly owned by the College Entrance Examination Board and the National Merit Scholarship Corporation.Educational Testing Service and ETS are registered trademarks of Educational Testing Service.。
AP物理C力学模拟卷Free Response Question
Free ResponseTime:45 minutes. You may refer to the Constants sheet and Equations sheet in the Appendixes. You may also use a calculator on this portion of the exam.CM 1Two 5-kg masses are connected by a light string over two massless, frictionless pulleys. Each block sits on a frictionless inclined plane, as shown above. The blocks are released from rest.a.Determine the magnitude of the acceleration of the blocks.b.Determine the tension in the string.Now assume that the 30° incline is rough, so that the coefficient of friction between the block and the plane is 0.10. The 60° incline is s till frictionless.1.Determine the magnitude of the acceleration of the blocks.2.Determine the tension in the string.CM 2A hollow glass sphere of radius 8.0 cm rotates about a vertical diameter with frequency 5 revolutions per second. A small wooden ball of mass 2.0 g rotates inside the sphere, as shown in the diagram above.a.Draw a free-body diagram indicating the forces acting on the woodenball when it is at the position shown in the picture above.b.Calculate the angle θ, shown in the diagram above, to which theball rises.c.Calculate the linear speed of the wooden ball as it rotates.d.The wooden ball is replaced with a steel ball of mass 20 g. Describehow the angle θto which the ball rises will be affected. Justify your answer.CM 3A heavy ball of mass m is attached to a light but rigid rod of length L. The rod is pivoted at the top and is free to rotate in a circle in the plane of the page, as shown above.a.The mass oscillates to a maximum angle θ. On the picture of themass m below, draw a vector representing the direction of the NET force on the mass while it is at angle θ. Justify your choice of direction.b.Is the magnitude of the net force at the maximum displacement equalto mg sinθ or mg cosθ? Choose one and justify your choice.c.Derive an expression for the ball's potential energy U as a functionof the angle θ. Assume that a negative angle representsdisplacement from the vertical in the clockwise direction.d.On the axes below, sketch a graph of the mass's potential energyU as a function of the angle θfor angles between –90° and +360°.Label maximum and minimum values on the vertical axis.e.The pendulum is considered a classic example of simple harmonicmotion when it undergoes small-amplitude oscillation. Withspecific reference to the graph you made in part (d), explain why the assumption of simple harmonic motion is valid.。
2017ap物理c力学真题答案
2017ap物理c力学真题答案一、单项选择题【答案】a考点：电磁感应现象与电流的磁效应现象分辨a.我国水资源是有限的，所以水能是不可再生能源b.发光二极管主要就是由超导材料制成的c.试电笔在使用时，试电笔上的任何金属都不要接触，否则会有触电危险d.工业上采用超音波探伤仪能够检查出来金属零件内部的裂纹【答案】 d【解析】我国水资源是有限的，但水能是可再生能源，a选项不正确;发光二极管是由半导体材料制成的，b选项不正确;使用试电笔时不能接触笔尖金属体，必须接触笔尾金属体，这样才能形成通路，c选项不正确;故d选项正确，选填d考点：再生能源辨识;发光二极管材料;试电笔的采用;超声波应用领域。
a.使用红外线传输数字信号b.使用超声波传输数字信号c.采用光纤传输数字信号d.采用电磁波传输数字信号【答案】d一、单项选择题a.电路中的电阻变大，灯泡变亮b.电路中的电阻变大，灯泡变暗c.电路中的电阻变大，灯泡变暗d.电路中的电阻变大，灯泡变暗【答案】c【考点定位】滑动变阻器【答案】a【解析】电流表的正确使用方法是：与被测用电器串联;电流必须从电流表的正极流入，负极流出;所测量的电流不能超过电流表的量程;绝对不允许不经过用电器把电流表直接接在电源两极上;电压表的正确使用方法是：把它并联在用电器两端;必须让电流从正接线柱流入，从负接线柱流出(正接线柱与正极相连，负接线柱与负极相连);被测电压不能超过电压表所选的量程，否则会烧坏电压表. a、此图中是电流表，即串联在电路中，且正负接线柱是正确的，故a正确;b、此图中是电流表，相当于导线，所以此时将电流表并联，会发生短路，故b错误;c、此图中是电压表，应该并联在用电器两端，故c错误;d、此图中的电压表虽然并联在用电器两端，但正负接线柱接反了，故d错误;故选a.【考点定位】电流表的采用;电压表的采用a.电流表接电源b.电压表接电源c.导线接电源d.家用电器接电源【答案】b【考点定位】电路的连接a.l1、l2两端实际电压相同b.l1、l2电阻之比是25:38c.l1、l2的电流之比为25 :38d.通过调节电源电压，能使l1、l2同时正常工作【答案】b【解析】【考点定位】并联电路的特点a.电流表与的示数的比值将减小b.电压表的示数与电流表的示数的比值将增大c.电压表的示数与电流表示数的乘积将增大d.电流表与的示数的比值将减小【答案】a【解析】由电路图知道r1与r2并联，a测量干路部分的电流，当滑动变阻器的滑片p向右移动时，r1接入电路的电阻增加，电路总电阻增加，所以a与a2的示数减小，v与a1的示数不变。
ap物理c答案
ap物理c答案【篇一：ap物理c】ass=txt>牛顿力学、占整个physics c力学考试的100%其中：a.kinematics ：运动学占18%包括：矢量（ vectors）的概念：既有大小，又有方向；矢量代数（ vector algebra）：矢量和的三角形法则是必须熟练掌握的，最简单的记忆方法就是花萌萌面对两段直的折线路径（对应两段位移矢量之和），她会选择直接连接出发点和终点的直线捷径（等效的对应两个位移矢量和），这样构成了一个矢量和三角形。
矢量的加减，点乘和叉乘，是矢量分析的基础，是我们学习ap物理c的基本数学框架一定要熟练掌握。
矢量在直角坐标系中的分量（components of vectors,coordinate systems）,特别强调的是物理上只会用“右手系”，也就是从x轴到y轴的右手螺旋拇指指向z轴，这个和叉乘的定义是一样的，好记！有了ta，大家在学电磁学的时候就不用左右手的拧麻花了。
ap 物理c还需要掌握柱坐标和球坐标，这在需要柱对称和球对称的积分问题时，就很有用了。
运动学中要用到的三大矢量：位移、速度和加速度（displacement, velocity and acceleration)，特别要注意别把距离（或者叫路程distance），速率（speed）和前面的概念搞混了，后两个概念是标量，只有在一些特殊情况下才和对应矢量的模（大小）相等。
一维运动（motion in one dimension）：一维运动的矢量性就记住有正负的方向就行，对于一维匀加速直线运动，务必掌握其最重要的三个方程：第一求速度的公式，角标i（initial）和f（final）总是代表初和末，这个公式只要从匀加速度等于平均加速度的定义就可以得到：第二个求位移的公式：，这个公式可以理解为保持初速度的匀速运动位移和初速为零的匀加速运动位移之和（第二项在v-t图中是一个三角形面积，底为⊿t，高为a*⊿t）第三个公式是把前面两个公式消去变量⊿t，得：更方便的记忆方法是公式左边用牛顿第二定律f=ma，变成外力做功的形式：f⊿x, 左边多出来的2/m转到右边，右边就正好得到物体动能的变化。
AP physics C 2004 真题 多项选择试题题目
AP physics C 2004 真题多项选择试题题目Questions 40-4136. Three 1/2 μF capacitors are connected in series as shown in the diagram above. Thecapacitance of the combination is (A) 0.1 μF (B) 1 μF (C) 2/3 μF(D) ? μF (E) 1/6 μF37. A hair dryer is rated as 1200 W, 120 V. Its effective internal resistance is(A) 0.1 Ω (B) A particle of charge +e and mass m moves with 10 Ω (C) 12Ω speed v perpendicular to a uniform magnetic field (D) 120 Ω (E) B directed into the page. The path of the particle is 1440 Ω a circl eof radius r, as shown above. 40. Which of the following correctly gives thedirection of motion and the equationrelating v and r ?Direction Equation(A) Clockwise eBr = mv 2 (B) Clockwise eBr = mv 38. A point charge+Q is inside an uncharged (C) Counterclockwise eBr = mv conducting spherical shell that in turn is near 2(D) Counterclockwise eBr = mv several isolated point charges, as shown above. 22(E) Counterclockwise eBr = mv The electric field at point P inside the shell depends on the magnitude of 41. The period of revolution of the particle (A) Q only is (B) the charge distribution on the sphere only (A) mr/eB (B) meB/(C) Q and the charge distribution on the sphere (D) all of the point charges (C) 2πm/eB (D) 2/,meB(E) all of the point charges a nd the charge (E)2/,mreBdistribution on the sphere 42. A 20 μF parallel-plate capacitor is fully charged to 30 39. In a certain region, the electric field along V. The energy stored in the capacitor is most nearly the x-axis is given by 3-3-4(A) 9 x 10 J (B) 9 x 10 J (C) 6 x 10 J 2E = ax + b, where a = 40 V/m -4-7(D) 2 x 10 J (E) 2 x 10 J and b = 4 V/m. The potentialdifference between the origin 43. A potential difference V is maintained between and x = 0.5 m is two large, parallel conducting plates. An (A) -36 V (B) -7 V (C) -3 V (D) 10 V electron starts from rest on the surface of one (E) 16 V plate and accelerates toward the other. Its speed as it reaches the second plate isproportional to(A) 1/V(B)1VV(C)(D) V 2(E) V44. A wire of radius R has a current I uniformly 48. Two conducting cylindrical wires are made outdistributed across its cross-sectional area. of the same material. Wire X has twice theAmpere's law is used with a concentric length and twice the diameter of wire Y. Whatcircular path of radius r, with r < R, to /R of their resistances?is the ratio Rxycalculate the magnitude of the magnetic (A) 1/4 (B) ? (C) 1 (D) 2 (E) 4field B at a distance r from the center of the wire. Which of the following equationsresults from a correct application ofAmpere's law to this situation? 22(A) B(2πr) = μI (B) B(2πr) =μI(r/R) 00(C) B(2πr) = 0 (D) B(2πR) = μI (E) B(2πR) 022= μI(r/R) 0Questions 45-4649. A solid metallic sphere of radius R has chargeQ uniformly distributed on its outer surface. Agraph of electric potential V as a function ofposition r is shown above. Which of thefollowing graphs best represents the magnitudeof the electric field E as a function of position r Particles of charge Q and -4Q are located on the for this sphere? x-axis as shown in the figure above. Assumethe particles are isolated from all other charges.45. Which of the following describes the directionof the electric field at point P ?(A) +x (B) +y (C)-y(D) Components in both the -x- and+y-directions(E) Components in both the+x- and -y-directions46. At which of the labeled points on the x-axis is the electric field zero?(A) A (B) B (C) C (D) D (E) E47. When the switch S is open in the circuitshown above, the reading on the ammeter Ais 2.0 A. When the switch is closed, thereading on the ammeter is(A) doubled(B) increased slightly but not doubled(C) the same(D) decreased slightly but not halved (E) halved50. Two parallel wires, each carrying a current I, repel each other with a force F. If bothcurrents are doubled, the force of repulsion is (A) 2F (B) F (C) 4F22(D) F (E) 8F 4251. A circular current-carrying loop lies so that the plane of the loop is perpendicular to a constant 54. A conducting loop of wire that is initially magnetic field of strength B. Suppose that the around a magnet is pulled away from the radius R of the loop could be made to increase magnet to the right, as indicated in the figure with time t so that R = at, where a is a constant. above, inducing a current in the loop. What is What is the magnitude of the emf that would be the direction of the force on the magnet and generated around the loop as a function of t ? 2the direction of the magnetic field at the (A) 2πBat(B) 2πBat (C) 2πBt 223center of the loop due to the (D) πBat (E) (π/3)Bat induced current? Direction ofMagnetic Field atDirection of Center of Loop dueForce on the Magnet to Induced Current(A) To the right To the right(B) To the right To the left(C) To the left To the right 52. The figures above show parts of two circuits, (D) To the left To the left(E) No direction; To the left each containing a battery of emf ε and internal the force is zero. resistance r. The current in each battery is 1 A, but the direction of the current in one battery is opposite to that in the other. If the potential differences across the batteries' terminals are 10 V and 20 V as shown, what are the valuesof ε and r ? 55. A square loop of wire carrying a current I is (A) ε = 5 V, r = 15 Ω initially in the plane of the page and is located in a uniform magnetic field B that points (B) ε =IOV, r=100 Ω toward the bottom of the page, as shown above. (C) ε = 15 V, r = 5 Ω Which of the following shows the correct initialrotati on of the loop due to the force exerted on (D) ε = 20 V, r = 10 Ωit by the magnetic field? (E) The values cannot be computed unless the complete circuits are shown.53. A charged particle can move withconstant velocity through a regioncontaining both an electric field and amagnetic field only if the(A) electric field is parallel to the magnetic field(B) electric field is perpendicular to the magnetic field(C) electric field is parallel to the velocity vector(D) magnetic field is parallel to the velocity vector(E) magnetic field is perpendicular to the velocity vectorQuestions 59-6156. In the circuit shown above, the equivalent The diagram above shows equipotential lines resistance of the three resistors is produced by an unknown charge distribution. A, (A) 10.5 Ω (B) 15Ω (C) 20 ΩB, C, D, and E are points in the plane. (D) 50 Ω (E) 115 Ω59. Which vector below best describes the direction Questions 57-58of the electric field at point A ?(A) (B) (C) (D)(E) None of these; the field is zero.60. At which point does the electric field havethe greatest magnitude? (A) A As shown in the figure above, six particles, each (B) B with charge +Q, are held fixed and ate equally(C) C spaced around the circumference of a circle of(D) D radius R.(E) E57. What is the magnitude of the resultantelectric field at the center of the circle? 61. How much net work must be done by anexternal force to move a -1 μC point charge 6Q(A) 0 (B) (C) from rest at point C to rest at point E ? 24,,R0(A) -20 μJ(B) -10 μJ 23Q32Q (D) 22(C) 10 μJ ,,,,4R4R00(D) 20 μJ 3Q(E) 30μJ (E) 2,,2R 058. With the six particles held fixed, how muchwork would be required to bring a seventhparticle of charge + Q from very far awayand place it at the center of the circle?23Q6Q(A) 0 (B) (C) 2,,,,24RR00229Q3Q(D) (E) ,,,,2R00R62. One of Maxwell's equations can be written 65. A physics problem starts: "A solid sphere hascharge distributed uniformly throughout. . . " d,as. This equation expresses ,,,Eds,It may be correctly concluded that the dt(A) electric field is zero everywhere inside the the fact that sphere (A) a changingmagnetic field produces (B) electric field inside the sphere is the same an electric field as the electric field outside (B) a changing electric field produces a (C) electric potential on the surface of the magnetic field sphere is not constant (C) the net magnetic flux through a (D) electric potential in the center of the sphere closed surface depends on the is zero current inside (E) sphere is not made of metal (D) the net electric flux through a closed surface depends on the charge inside Questions 66-67 relate to the circuit represented (E) electric charge is conserved below. The switch S, after being open for a long time, is then closed., ,12 V4 HS63. The plates of a parallel-plate capacitor of cross 66. What isthe current in the circuit after the sectional area A are separated by a distance d, switch has been closed a long time? as shown above. Between the plates is a (A) 0 A dielectric material of constant K. The plates are (B) 1.2 A connected in series with a variable resistance R (C) 2 A and a power supply of potential difference V. (D) 3 A The capacitance C of this capacitor will (E) 12 A increase if which of the following isdecreased? (A) A (B) R (C) K 67. What is the potential difference across the (D) d (E) V resistor immediately after the switch is closed? (A) 0 V(B) 2 V(C) 7.2 V(D) 8 V(E) 12 V68. A uniform spherical charge distribution hasradius R.. Which of the following is true of the electric field strength due to this charge 64. The currents in three parallel wires, X, Y, and Z, distribution at a distance r from the center of each have magnitude l and are in the directions the charge? shown above. Wire Y is closer to wire X than to (A) It is greatest when r = 0. wire Z. The magnetic force on wire Y is (B) It is greatest when r = R/2. (A) zero (B) into the page (C) out of the page (C) It is directly proportional to r when r > (D) toward the bottom of the page R. (E) toward the left (D) It is directly proportional to r when r < R. 2(E) It is directlyproportional to r.69. When a negatively charged rod is brought near, but does not touch, the initially uncharged electroscope shown above, the leaves spring apart (I). When the electroscope is then touched with a finger, the leaves collapse (II). When next the finger and finally the rod are removed, the leaves spring apart a second time (III). The charge on the leaves is(A) positive in both I and III(B) negative in both I and III(C) positive in I, negative in III(D) negative in I, positive in III(E) impossible to determine in either I or III70. A sheet of copper in the plane of the page is connected to a battery as shown above, causing electrons to drift through the copper toward the bottom of the page. The copper sheet is in a magnetic field B directed intothe page. P and P are points at the edges of 12the strip. Which of the following statements is true?(A) P is at a higher potential than P. 12(B) P is at a higher potential than P. 21(C) P and P are at equal positive potential. 12(D) P and P are at equal negative potential. 12(E) Current will cease to flow in the copper sheet.。
ap物理c】真题】解答题c2000
【AP物理C】【真题】解答题C2000AP? Physics C2000 Free response QuestionsThe mat erials included in these files are intended for use by AP teachers for course and exam preparation in the classroom; permission for any other use must be sought from the Advanced Placement Program?. Teachers may reproduce them, in whole or in part, in limited quantities, for face-to-face teaching purposes but may not mass distribute the materials, electronically or ot herwise. These mat erials and any copies made of t hem may not be resold, and the copyright notices must be retained as they appear here. This permission does not apply to any third-party copyrights contained herein.These materials were produced by Educational Testing Service? (ETS?), which develops and administers the examinations of the Advanced Placement Program for the College Board. The College Board and Educational Testing Service (ETS) are dedicated to the principle of equal opportunity, and their programs, services, and employment policies are guided by that principle.The College Board is a national nonprofit membershipassociation dedicated to preparing, inspiring, and connecting students to college and opportunity. Founded in 1900, the association iscomposed of more than 4,200 schools, colleges, universities, and other educational organizations. Each year, the College Board serves over three million students and their parents, 22,000 high schools, and 3, 500 colleges, through major programs and services in college admission, guidance, assessment, financial aid, enrollment, and teaching and learning・ Among its best-known programs are the SAT?, the PSAT/NMSQT?, and the Advanced Placement Program? (AP?). The College Board is committed to the principles of equity andexcellence, and that comm it men t is embodied in allof its programs, services, activities, and concerns.API EL is a trademark owned by the College Ent rance Examination Board・ PSAT/NMSQT is a registeted trademark jointly owned by the College Entrance Examination Board and the National Merit Scholarship Corporation. Educational Testing Service and ETS are registered trademarks of Educational Testing Service.Copyright ? 2000 by College Entrance Examination Board.All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.(2000 Ml) You are conducting an experiment to measure the acceleration due to gravity gu at an unknown location. In the measurement apparatus, a simple pendulum swings past a photogate located at the pendulum^ s lowest point, which records the time tlO for the pendulum to undergo 10 full oscillations. The pendulum consists of a sphere of mass m at the end of a st ring and has a leng th 1. There are four versions of this apparatus, each with a different length. All four are at the unknown location, and the data shown below are sent to you during the experiment.tio T T2 ? (s) (s) (s2) (cm) 12 18 21 32 a. For each pendulum, calculate the period T and the square of the period. Use a reasonable number of signifies nt figures. Enter these results in the table above.b.On the axes below, plot the square of the period versus the length of the pendulum. Draw a best-fit straight linefor this data. c. Assuming that each pendulum undergoessmall amplitude oscillations, from your fit determine the experimental value gexp of the acceleration due to gravity at this unknown location. Justify your answer.d.If the measurement apparatus allows a determination of gexp that is accurate to within 4%, is your experimentalvalue in agreement with the value m/s2 ? Justify your answer.e.Someone informs you that the experimental appara tus is in fac t neat Ear th's surface, but that the experiment hasbeen conducted inside an elevator with a constant acceleration a. Assuming that your experimental value g is exact, determine the magnitude and direction of the elevatoH s acceleration.Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registeted trademarks of the College Entrance Examination Board.2000M2. A rubber ball of mass m is dropped from a cliff. As the ball falls, it is subject to air drag (a resistiveforce caused by the air). The drag force on the ball has magnitude bv2, where b is a constant drag coefficient and v is the instantaneous speed of the ball. The drag coeff icie nt b is direc tly proportional to the cross-sectional area of the ball and the density of the air and does not depend on the mass of the ball. As the ball falls, its speed approaches a constant value called the terminal speed.a.On the figure below, draw and label all the forces on the ball at some instant before it reaches terminal speed.b.State whether the magnitude of the acceleration of the ball of mass m increases, decreases, or remains the sameas the ball approaches terminal speed. Explain.c.Write, but do NOT solve, a differential equation for the instantaneous speed v of the ball in terms of time t, thegiven quantities, and fundamentai constants.d.Det ermine the terminal speed vt in t erms of the given quantities and fundamental constants.e.Determine the energy dissipated by the drag force during the fall if the ball is released at height h and reachesits terminal speed before hitting the ground, in terms of the given quantities and fundamental constants.2000M3・ A pulley of radius R1 and rotational inertiaII is mounted on an axle with negligible friction. A light cord passing over the pulley has two blocks of mass m attached to either end, as shown above. Assume that the cord does not slip on the pulley. Det ermine the answers to parts (a) and (b) in t erms of m, Rl, II, and fundamental constants, a. Determine the tension T in the cord.b.One block is now removed from the right and hung on the left・ When the system is released from rest, the threeblocks on the left accelerate downward with an accelera tion g/3 • Det ermine the following, i. The tension T3 in the section of cord supporting the three blocks on the left ii. The tension T1 in the section of cord supporting the single block on the right iii. The rotational inertia II of the pulleyCopyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the CollegeEntrance Examination Board.c.The blocks are now removed and the cord is tied into a loop, which is passed around the original pulley and asecond pulley of radius 2R1 and rotational inertia 1611. The axis of the original pulley is attached to a motor that rotates it at angular speed ?1, which in turn causes the larger pulley to rotate. The loop does not slip on the pulleys. Det ermine the following in terms of II, RI, and ?1. i. The angular speed ?2 of the larger pulleyii. The angular momentum L2 of the larger pulley iii. The totai kinetic energy of the system2000E1. Lightbulbs A, B, and C are connected in the circuit shown above.a.List the bulbs in order of t heir brigh tn ess, from brightest to least bright・ If any bulbs have the same brightness,state which ones. Justify your answer.Now a switch S and a mH indue tor are added to the circuit; as shown above. The switch is closed at time t二0・b.Det ermine the curre nts IA, IB, and IC for the following times. i. Immediately after the switch is closedii. A long time after the switch is closedCopyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.c.On the axes below, sketch the magnitude of the potential difference VL across the inductor as a function of time,from immediately after the switch is closed untila long time after the switch is closed.d.Now consider a similar circuit with an uncharged ?F capacitor instead of the induetor, as shown above. Theswitch is again closed at time t 二0・ On the axes below, sketch the magnitude of the potential difference Vcap across the capacitor as a function of time, from immediately after the switch is closed until a long time after the switch is closed.Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.2000E2・Three particles, A, B, and C, have equal positive charges Q and are held in place at the vertices of anequilater&l triangle with sides of length 1, as shown in the figures below. The dot ted lines represe nt the bisec tors for each side. The base of the t riangle lies on the x-axis, and the altitude of the triangle lies on the y-axis.a.i.Point Pl, the intersection of the three bisec to rs, loca tes the geometric center of the triangle and is one pointwhere the electrie field is zero. On Figure 1 above, draw the elec trie field vec tors EA, EB, and EC at P, due to each of the three charges. Be sure your arrows are drawn to reflect the relative magnitude of the fields・ii.Another poi nt where the elec trie field is zero ispoint P2 at (0, y2). On Figure 2 above, draw electrie field vectors EA, EB, and EC at P2 due to each of the three point charges. Indicate below whether the magnitude of each of these vectors is greater than, less than, or the same as for point Pl.EA EB EC Greater than at Pl Less than at Pl The same as at Pl b. Explain why the x-component of the total electric field is zero at any point on the y-axis.c.Write a general expression for the electrie potential V at any point on the y-axis inside the trianglein terms of Q,1, and y.d.Describe how the answer to part (c) could be used to determine the y-coordinates of points Pl and P2 at whichthe electric field is zero. (You do not need toactually determine these coordinates.)Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.2000E3. A capacitor consists of two conducting, coaxial, cylindrical shells of radius a and b, respec ti vely, and leng th L » b. The space bet ween the cylinders is filled with oil that has a dielectric constant K .Initially bothcylinders are uncharged, but then a battery is used to charge the capacitor, leaving a charge +Q on the inner cylinder and -Q on the outer cylinder, as shown above. Let r be the radial distance from the axis of the capacitor.ing Gauss，s 1aw, determine the electrie field midway along the length of the cylinder for the following valuesof r, in t erms of the given qua ntities and fundamental constants. Assume end effects are negligible. i.a b. Determine the following in terms of the givenquantities and fundamentai constants.i. The potential difference across the capacitor ii. The capacitance of this capacitorc.Now the capacitot is discharged and the oil is drained from it. As shown above, a battery of emf ? is connectedto opposite ends of the inner cylinder and a battery of emf 3? is connected to opposite ends of the outer cylinder. Each cylinder has resistance R. Assume that end effects and the contributions to the magnetic field from the wires are negligible. Using Ampere" s law, determine the magnitude Bof the magnetic field midway along the length of the cylinders due to the current in the cylinders for the following values of r. i. a Copyrigh t ? 2000 by College Ent rance Examina tion Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.AP? Physics C2000 Free response QuestionsThe mat erials included in these files are intended for use by AP teachers for course and exam preparation in the classroom; permission for any other use must be sought from the Advanced Placement Program?. Teachers may reproduce them, in whole or in part, in limited quantities, for face-to-face teaching purposes but may not mass distribute the materials,electronically or otherwise. These mat erials and any copies made of t hem may not be resold, and the copyright notices must be retained as they appear here. This permission does not apply to any third-party copyrights contained herein.These materials were produced by Educational Testing Service? (ETS?), which develops and administers the examinations of the Advanced Placement Program for the College Board. The College Board and Education&l Testing Service (ETS) are dedicated to the principle of equal opportunity, and theirprograms, services, and employment policies are guided by that principle.The College Board is a national nonprofit membership association dedicated to preparing, inspiring, and connecting students to college and opportunity. Founded in 1900, the association iscomposed of more than 4,200 schools, colleges, universities, and other educational organizations. Each year, the College Board serves over three million students and their parents，22,000 high schools, and 3, 500 colleges, through major programs and services in college admission, guidance, assessment, financial aid, enrollment, and teaching andlearning・ Among its best-known programs are the SAT?, the PSAT/NMSQT?, and the Advanced Placement Program? (AP?). The College Board is committed to the principles of equity andexcellence, and that commitment is embodied in all of its programs, services, activities, and concerns.API EL is a trademark owned by the College Ent rance Examination Board・PSAT/NMSQT is a registeted trademark jointly owned by the College Entrance Examination Board and the National Merit Scholarship Corporation. Educational Testing Service and ETS are registered trademarks of Educational Testing Service.Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.(2000 Ml) You are conducting an experiment to measure the acceleration due to gravity gu at an unknown location. In the measurement apparatus, a simple pendulum swings past a photogate located at the pendulum^ s lowest point, which records the time tlO for the pendulum to undergo 10 fulloscillations. The pendulum consists of a sphere of mass m at the end of a st ring and has a length 1. There are four versions of this apparatus, each with a different length. All four are at the unknown location, and the data shown below are sent to you during the experiment.tio T T2 ? (s) (s) (s2) (cm) 12 18 21 32 a. For each pendulum, calculate the period T and the square of the period. Use a reasonable number of significant figures. Enter these results in the table above.b.On the axes below, plot the square of the period versus the length of the pendulum. Draw a best-fit straight linefor this data. c. Assuming that each pendulum undergoes small amplitude oscillations, from your fit determine the experimentai value gexp of the acceleration due to gravity at this unknown location. Justify your answer.d.If the measurement apparatus allows a determination of gexp that is accurate to within 4%, is your experimentalvalue in agreement with the value m/s2 ? Justify your answer.e.S omeone informs you that the experimental apparatus isin fact near Earth^ s surface, but that the experiment has been conducted inside an elevator with a constant acceleration a. Assuming that your experimentai value g is exact, determine the magnitude and direction of the elevatoH s acceleration.Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.2000M2. A rubber ball of mass m is dropped from a cliff. As the ball falls, it is subject to air drag (a resistive force caused by the air). The drag force on the ball has magnitude bv2, where b is a const&nt drag coefficient and v is the instantaneous speed of the ball. The drag coefficient b is directly proportional to the cross-sectional area of the ball and the density of the air and does not depend on the mass of the ball. As the ball falls, its speed approaches a constant value called the terminal speed.a.On the figure below, draw and label all the forces on the ball at some inst&nt before it reaches terminal speed.b.State whether the magnitude of theacceleration of the ball of mass m increases, decreases, or remains the sameas the ball approaches terminal speed. Explain.c.Write, but do NOT solve, a differential equation for the instantaneous speed v of the ball in terms of time t, thegiven quantities, and fundamentai constants.d・Determine the terminal speed vt in terms ofthe given quantities and fundamental constants.e. Determine the energy dissipated by the drag force during the fall if the ball is released at height h and reachesits terminal speed before hitting the ground, in terms of the given quantities and fundamental constants.2000M3・ A pulley of radius R1 and rotational inertiaII is mounted on an axle with negligible friction. A light cord passing over the pulley has two blocks of mass m attached to either end, as shown above. Assume that the cord does not slip on the pulley.Determine the answers to parts (a) and (b) in terms of m, Rl, II, and fundamental constants. a. Determine the tension T in the cord.b.One block is now removed from the right and hung on the left・ When the system is released from rest, the threeblocks on the left accelerate downward with an accelera tion g/3 • Det ermine the followin g, i. The tension T3 in the section of cord supporting the three blocks on the left ii. The tension T1 in the section of cord supporting the single block on the right iii. The rotation&l inertia II of the pulleyCopyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.c.The blocks are now removed and the cord is tied into a loop, which is passed around the original pulley and asecond pulley of radius 2R1 and rotational inertia 1611. The axis of the original pulley is attached to a motor that rotates it at angular speed ?1, which in turn causes the larger pulley to rotate. The loop does not slip on the pulleys.Det ermine the following in terms of II, RI, and ?1. i. The angular speed ?2 of the larger pulleyii. The angular momentum L2 of the larger pulley iii. The total kinetic energy of the system2000E1. Lightbulbs A, B, and C are connected in the circuit shown above.a.List the bulbs in order of t heir brigh tn ess, from brightest to least bright. If any bulbs have the same brightness,state which ones. Justify your answer.Now a switch S and a mH indue tor are added to the circuit; as shown above. The switch is closed at time t 二0.b.Det ermine the curre nts IA, IB, and IC for the following times. i. Immediately after the switch is closed ii. A long time after the switch is closedCopyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board.c.On the axes below, sketch the magnitude of thepotenti&l difference VL across the inductor as a function of time,from immediately after the switch is closed unt订a long time after the switch is closed.d.Now consider a similar circuit with an uncharged ?F capacitor instead of the inductor, as shown above. Theswitch is again closed at time t = 0. On the axes below, sketch the magnitude of the potential difference Vcap across the capacitor as a function of time, from immediately after the switch is closed until a long time after the switch is closed.Copyright ? 2000 by College Entrance Examination Board. All rights reserved.College Board, Advanced Placement Program, AP, SAT,and the acorn logo are registered trademarks of theCollege Entrance Examination Board.。
ap物理c力学试卷
选择题一个物体在水平面上做匀速直线运动，若突然撤去所有外力，物体将如何运动？A. 继续做匀速直线运动（正确答案）B. 逐渐减速至停止C. 开始做匀加速直线运动D. 做曲线运动下列哪个力是弹力？A. 重力B. 摩擦力C. 电磁力D. 弹簧的拉力（正确答案）一个物体在竖直上抛运动中，到达最高点时，它的速度为零，此时它的加速度是？A. 零B. 9.8 m/s²（正确答案）C. -9.8 m/s²D. 无法确定关于牛顿第三定律，下列说法正确的是？A. 作用力和反作用力大小相等，方向相同B. 作用力和反作用力作用在不同物体上（正确答案）C. 作用力和反作用力可以相互抵消D. 作用力先于反作用力产生一个物体在恒力作用下做匀加速直线运动，如果突然将力的大小减半，但方向不变，物体的运动状态将如何变化？A. 继续做匀加速直线运动，但加速度减小（正确答案）B. 开始做匀速直线运动C. 开始做匀减速直线运动D. 做曲线运动下列哪个选项描述了动量守恒定律的适用条件？A. 系统不受外力作用或所受合外力为零（正确答案）B. 系统内各物体速度必须相同C. 系统内各物体加速度必须相同D. 系统内各物体质量必须相等一个物体在光滑的水平面上受到一个水平恒力的作用，它将做何种运动？A. 匀速直线运动B. 匀加速直线运动（正确答案）C. 匀减速直线运动D. 曲线运动关于冲量，下列说法正确的是？A. 冲量是矢量，方向与力的方向相同（正确答案）B. 冲量是标量，只有大小没有方向C. 冲量的大小等于力与时间的乘积，方向与速度方向相同D. 冲量的大小等于力与位移的乘积一个物体在竖直方向上受到重力和空气阻力的作用，下落过程中它的加速度将如何变化？A. 保持不变B. 逐渐增大C. 逐渐减小（正确答案，假设空气阻力随速度增大而增大）D. 先增大后减小。