AP Physics Name _________________________ Practice Exam 2 Period _____ Multiple Choice (No calculator) 1. A person throws a marble straight up into the air, releasing 7. An object weighing 120 N is set on a rigid beam of it a short height above the ground and catching it at that negligible mass at a distance of 3 m from a pivot. A vertical same height. If air resistance is negligible, which of the force is to be applied to the other end of the beam a following graphs of position y versus time t is correct for distance of 4 m from the pivot to keep the beam at rest and the motion of the marble as it goes up and then comes horizontal. down? What is the magnitude F of the force required? (A) 10 N (B) 30 N (C) 90 N (D) 120 N Questions 8-10 A block released from rest at position A slides with negligible friction down an inclined track, around a vertical loop, and then along a horizontal portion of the track. The block never leaves the track. 2. A rocket lifts a payload upward from the surface of earth. The radius of earth is R, and the weight of the payload on the surface of earth is W. The force of earth's gravity on the payload is W/2 when the rocket's distance from the center of earth is (A) R (B) R (C) 2R (D) 22R 8. After the block is released, in which of the following sequences of positions is the speed of the block ordered from fastest to slowest? (A) B C D E (B) B E C D Questions 3-4 An object is thrown with an initial speed v near (C) D C E B (D) E B C D the surface of earth. Assume that air resistance is negligible and the gravitational field is constant. 3. If the object is thrown vertically upward, the direction and magnitude of its acceleration while it is in the air is 9. Which of the following is true of the net force on the block (A) upward and decreasing when it is at position C? (B) upward and constant (A) It is directed vertically downward only. (C) downward and increasing (B) It is directed vertically upward only. (D) downward and constant (C) It is directed to the left only. (D) It has components both to the left and vertically downward. 4. If the object is thrown horizontally, the direction and magnitude of its acceleration while it is in the air is (A) upward and decreasing 10. The gravitational potential energy and the kinetic energy of (B) upward and constant the block are most nearly equal at which position? (C) downward and increasing (Consider the potential energy to be zero at position B.) (D) downward and constant (A) A (B) B (C) C (D) D -5 5. Inertia can be best described as the 11. What is the acceleration of an object of mass 4.5 x 10 kg -9 (A) force that keeps an object in motion with constant with a charge of 9 x 10 C under the influence of an velocity electric field of magnitude 5000 V/m, assuming gravity is (B) force that keeps an object at rest negligible? 2 2 (C) force that overcomes friction (A) 0.05 m/s (B) 0.5 m/s 2 2 (D) property responsible for an object's resistance to (C) 0.9 m/s (D) 1.0 m/s changes in motion 12. An object is placed 12 cm in front of a concave mirror. The 6. At room temperature and one atmosphere of pressure, mirror forms a real inverted image that is the same size as which of the following materials is the best conductor of the object, also at 12 cm in front of the mirror. The focal heat? length of the mirror is (A) Air (B) Helium (C) Silver (D) Water (A) 3.0 cm (B) 4.0 cm (C) 6.0 cm (D) 12 cm 13. A 60 W, 120 V light bulb has a resistance of 18. A charged particle is in a region that contains both an (A) 0.5 (B) 2.0 (C) 120 (D) 240 electric and a magnetic field. The kinetic energy of the particle is 9 J at point X and 11 J at point Y in the figure below Questions 14-15 A sample of an ideal gas is taken through the cycle abca, as shown in the PV diagram. If the only forces present are electromagnetic, what is the work done by the electric force on the particle as it moves from X to Y along the path shown? (A) 0 J (B) 1 J (C) 2 J (D) 11 J Questions 19-20 The following are configurations of electric charges located at the vertices of an equilateral triangle. Point P is in the plane of the triangle and equidistant from 14. What is the change in internal energy of the gas for the the charges. process bc? (A) (B) (A) -1500 J (B) -500 J (C) 0 J (D) +500 J 15. If 1000 J of heat is added to the gas during process ab, what is the change in internal energy of the gas for process ab? (A) -2000 J (B) -1000 J (C) 0 J (D) +1000 J (C) (D) 16. Two point charges of unknown magnitudes q1 and q2 are placed where the electric field intensity is zero at point P, which is closer to q1 than to q2. 19. In which configuration is the electric field at P pointed directly toward one of the charges? Which of the following is true of the signs of the charges and their magnitudes? 20. In which configuration is the electric potential at P equal to Signs Magnitudes zero? (A) Opposite q1 < q2 (B) Opposite q1 > q2 (C) Same q1 > q2 21. Consider the circuit. (D) Same q1 < q2 17. A conducting spherical shell of radius R has charge q uniformly distributed on its outer surface. The graph below represents electric field strength E versus distance r from What is the current in the 5 resistor? the center of the spherical shell. (A) 40 A (B) 25 A (C) 20 A (D) 10 A 22. Balls 1 and 2 are each thrown horizontally from the same height above level ground, but ball 2 has a greater initial velocity after leaving the thrower's hand. If air resistance is negligible, how do the accelerations of the balls and the times it takes them to hit the ground compare? Which of the following graphs best represents E versus r Acceleration a Time to Hit Ground when the charge on the spherical shell is doubled to 2q? (A) Greater for ball 2 Greater for ball 2 (B) Greater for ball 2 Equal (C) Equal Greater for ball 2 (D) Equal Equal 23. Two objects, X and Y, accelerate from rest with the same constant acceleration. Object X accelerates for twice the time as object Y. Which of the following is true of these objects at the end of their respective periods of acceleration? (A) Object X is moving four times faster than object Y. (B) Object X has traveled the same distance as object Y. (C) Object X has traveled twice as far as object Y. (D) Object X has traveled four times as far as object Y. 24. A builder is replacing a concrete wall with a wooden one 32. The two wave pulses, X and Y, shown below are moving and wants the new wall to have the same area and rate of toward each other in the same medium. heat flow through it as the old wall. The thermal conductivities of wood and concrete are 0.1 W/m•K and 0.8 W/m•K, respectively. If the concrete wall is 40 cm thick and the temperature difference across the two walls is the same, what thickness of wooden wall is needed? (A) 2 cm (B) 4 cm (C) 5 cm (D) 20 cm Which of the following interference patterns could result at some instant as the pulses pass through each other? 25. A series of measurements are made of the pressure P and the volume V of a sample of nitrogen gas kept at a constant temperature. It is desired to represent the data graphically so that the graph will be a straight line if the behavior of the gas is ideal. Accordingly, which of the following should be plotted? (A) P vs. V (B) V/P vs. V -1 (C) P/V vs. V (D) P vs. V (A) I only (B) II only (C) I and III only (D) II and III only 26. At a point of observation, the time between successive crests of a passing wave is 0.2 s. Which of the following must be true of the wave? 33. The figure shows a portion of the energy level diagram for (A) Wavelength is 0.2 m. (B) Wavelength is 5 m. hydrogen. Possible transitions among the energy levels (C) Period is 5 s. (D) Frequency is 5 Hz. are represented by arrows I, II, and III. 27. Which of the following experimental observations provides the best support for the statement, "Light behaves like a wave"? (A) Light can be reflected by a mirror. (B) Light is scattered when passing through smoke. (C) Monochromatic light forms bright and dark bands after passing through two narrow slits. Which of the following lists the transitions in order of their (D) White light can be broken into component colors by a associated wavelengths of light, from shortest wavelength prism. to longest wavelength? (A) I, II, III (B) I, III, II (C) II, I, III (D) II, III, I 28. When a light wave passes from air into glass, quantities that remain constant include which of the following? 34. A railroad car of mass m is moving with speed v when it I. Frequency II. Wavelength III. Speed collides with and connects to a second railroad car of mass (A) I only (B) II only 3m, initially at rest, as shown below. (C) I and III only (D) II and III only 238 29. 92U undergoes a series of reactions in which it emits 4 eight 2He nuclei and six electrons. What is the isotope that How do the speed and kinetic energy of the connected results from this series of reactions? cars compare to those of the single car of mass m before 222 206 206 207 (A) 66Dy (B) 81Tl (C) 82Pb (D) 82Pb the collision? Speed Kinetic Energy 2 (A) Less Less 30. A deuterium nucleus 1H interacts with a lithium nucleus (B) Less The same 7 3Li. Which of the following could NOT possibly occur as (C) The same Less the end products of this reaction because of violation of (D) The same The same conservation of charge or mass number? 4 3 2 3 1 1 (A) 2He + 1H + 1H (B) 2 1H+ 1H + 2 0n 4 1 7 2 (C) 2 2He + 0n (D) 3Li + 1H 35. A simple pendulum consisting of a small object of mass m attached to a string of length L has a period T. A pendulum with which of the following combinations of object mass 31. A ball of mass m and momentum p has kinetic energy and string length will also have period T? equal to which of the following? Object Mass String Length 2 2 (A) ½p /m (B) p /m (A) m/2 L 2 2 (C) 2p /m (D) ½m/p (B) m L/4 (C) 2m L/2 (D) 2m 4L 36. A planet of mass m orbits a star of mass M, where m << M. 43. What is the magnitude of the average frictional force The orbit is circular, its radius is r, and its period is T. True exerted on the block by the rough section of the surface? statements about the planet's orbit include which of the (A) 30 N (B) 12 N (C) 4.5 N (D) 4 N following? I. The orbital speed equals 2r/T. II. The gravitational force equals GMm/r . 2 44. An object attached to one end of a string moves in a circle III. If the orbital radius r were greater, T would also at constant speed. Which of the following is correct? be greater. (A) The object is accelerating as it moves. (A) I only (B) II only (B) The object's velocity is the same as its speed. (C) I and III only (D) I, II, and III (C) The object does not require a force to keep its state of circular motion. (D) If the string breaks, the object will keep its circular Questions 37-38 Helium gas is flowing steadily through the pipe motion. shown. The diameter of the pipe at the left end is 2.00 x -2 -2 10 m and at the right is 1.00 x 10 m. The flow is slow enough that the density of the gas remains essentially 45. The index of refraction of air increases linearly with its -3 3 constant. The volume flow rate is 2.00 x 10 m /s. density. A ray of light passes through an interface from vacuum into air. Statements that are true as the air is heated at constant pressure include which of the following? I. The frequency of refracted light in air decreases. II. The wavelength of refracted light in air decreases. III. The speed of light in air increases. 37. The speed of the gas in the right end of the pipe is how (A) II only (B) III only many times the speed in the left end? (C) I and II (D) II and III (A) 1/4 (B) 1/2 (C) 2 (D) 4 46. Three point charges, +q, +Q, and -Q, are fixed at the 38. What is the speed of the gas in the left end of the pipe? corners of an isosceles triangle in the plane of the page. -5 (A) 4 x 10 m/s (B) 0.10 m/s (C) 0.20 m/s (E) 20/ m/s 39. The pressure exerted on the bottom of a dam by the water in the reservoir created by the dam depends on the (A) shape of the dam (B) area of the dam (C) depth of the water at the dam (D) surface area of the reservoir Which arrow in the figure represents the direction of the net electrostatic force on charge +q due to the other two 40. A 3.0 kg block hanging from a spring scale is submerged in equal and opposite charges? a beaker of water until the spring scale reads 20 N. What (A) A (B) B (C) C (D) D is the buoyant force on the block? (A) 10 N (B) 17 N (C) 37 N (D) 50 N 47. The wavelength of yellow sodium light in vacuum is -7 approximately 6.0 x 10 m. The frequency of the light is 41. The magnetic flux for each turn of a 20-turn coil decreases 2 most nearly from 0.30 T•m to zero in 2 s. The emf induced in the coil is -15 (A) 2.0 x 10 Hz (B) 1.8 Hz (A) 2 V (B) 3 V 2 14 (C) 1.8 x 10 Hz (D) 5.0 x 10 Hz (C) 6 V (D) 9 V 48. Two lenses are arranged so that a narrow laser beam of Questions 42-43 A block of mass 3 kg slides along a horizontal parallel rays spreads into a wider beam of parallel rays. surface that has negligible friction except for one section. The block arrives at the rough section with a speed of 5 m/s and leaves it 0.5 s later with a speed of 3 m/s. If the lenses are interchanged, the light in region 3 will be a beam of (A) parallel rays narrower than the beam in region I 42. What is the magnitude of the work done by the frictional (B) parallel rays wider than the beam in region I force exerted on the block by the rough section? (C) parallel rays about the same width as in region 1 (A) 24 J (B) 16 J (C) 8 J (D) 6 J (D) diverging rays 49. The magnet shown below is initially far away from the 54. Two skaters are initially at rest next to each other on conducting loop and is moved at constant speed toward frictionless ice. Skater A pushes on skater B. If skater A and completely through the loop. has greater mass than skater B, which of the following correctly relates the magnitudes of their momentums p and their kinetic energies K after the push? (A) pA = pB and KA < KB (B) pA = pB and KA = KB (C) pA = pB and KA > KB (D) pA < pB and KA < KB If T is the time at which the magnet is halfway through the 55. Current I flows into and out of the page in two parallel, loop, which of the following graphs best represents the long, straight wires that are fixed at two vertices of an induced current I in the loop as a function of time t? equilateral triangle. The net magnetic field at the third vertex (point P) due to these currents is in which of the following directions? (A) (B) (C) (D) 56. One section of wire in the circuit above lies in a region 50. Traveling waves are generated on a string fixed at both containing a magnetic field B directed into the page. ends. The string has a length L, a linear mass density , and a tension T. Which of the following will cause the wave speed to increase? I. Using the same string but increasing the tension II. Using a longer string with the same and T III. Using a string with the same L and T but smaller (A) I only (B) II only (C) III only (E) I or III The magnetic force on the section of wire is directed (A) toward the right 51. Which of the following is true of the conservation of (B) toward the left momentum and kinetic energy? (C) toward the top of the page (A) Momentum is conserved only in elastic collisions. (D) toward the bottom of the page (B) Momentum is conserved only in inelastic collisions. (C) Kinetic energy is conserved only in elastic collisions. (D) Kinetic energy is conserved only in inelastic collisions. 57. A student wants to determine experimentally, without disconnecting any wires in the circuit, the DC current moving through a copper wire. Which of the following 52. When a voltage V1 is connected across a capacitor of items of laboratory equipment would be sufficient to make capacitance C1, charges of equal magnitude Q1 and the necessary measurements for this determination? opposite sign are on the plates, and the energy stored in (A) Magnetic field sensor only the capacitor is U1. If C2 = 2C1 and V2 = V1, how are Q2 (B) Magnetic field sensor and meter stick and U2 affected? (C) Bar magnet and meterstick Q2 U2 Q2 U2 (D) Stopwatch and meterstick (A) = ½Q1 = ½U1 (B) = ½Q1 = ¼U1 (C) = Q1 = U1 (D) = 2Q1 = 2U1 58. A force of constant magnitude F and fixed direction acts on an object of mass m that is initially at rest. If the force acts 53. Consider the diagram below. for a time interval t over a displacement x, what is the magnitude of the resultant change in the linear momentum of the object? (A) Ft (B) Fx (C) Ft/m (D) Fx/m 59. A ball is thrown with an initial speed of 20 m/s at an angle What is the equivalent capacitance between points P and Q? of 60° to the ground. If air resistance is negligible, what is (A) 6 F (B) 24 F (C) 25 F (D) 50 F the ball's speed at the instant it reaches its maximum height from the ground? (A) Zero (B) 10 m/s (C) 14 m/s (D) 17 m/s 60. The maximum energy of photoelectrons emitted from a 66. A student working with glass objects and silvered mirrors metal surface depends on which of the following? traces light rays in the laboratory. Which of the following I. The intensity of the incident light ray tracings is drawn most correctly? II. The frequency of the incident light (A) (B) III. The work function of the metal (A) I only (B) III only (C) I and II only (D) II and III only (C) (D) 61. For the hydrogen atom, how does the potential energy U of the atom change as the energy level n increases? (A) The potential energy always increases. (B) The potential energy always decreases. (C) The potential energy increases, then decreases. (D) The potential energy decreases, then increases. 67. In a lab, a block weighing 80 N is attached to a spring 62. The present theory of the nature of light suggests that it scale, and both are pulled to the right on a horizontal (A) is a wave only surface. Friction between the block and the surface is (B) consists of particles only negligible. (C) is a mixture of both waves and particles (D) exhibits either wave or particle properties depending on the situation 63. An object PQ is located to the left of a converging lens What is the acceleration of the block when the scale reads having focal points F. 32 N? 2 2 2 2 (A) 2.0 m/s (B) 2.5 m/s (C) 4.0 m/s (D) 6.0 m/s 68. A box is given a sudden push up a ramp. Friction between the box and the ramp is not negligible. Which of the following diagrams best represents the directions of the The image formed by the lens is actual forces acting on the box as it moves upward after (A) real, inverted, and smaller than the object the push? (B) real, inverted, and larger than the object (C) real, upright, and larger than the object (D) virtual, upright, and larger than the object 64. The system shown below is released from rest. If friction is negligible, the acceleration of the 4.0 kg block 69. A small car with mass m and speed 2v and a large car with sliding on the table shown above is most nearly mass 2m and speed v both travel the same circular section 2 2 2 (A) 0 (B) 1.7 m/s (C) 3.3 m/s (D) 5.0 m/s of an unbanked road. If the frictional force required to keep the small car on the road without skidding is F, then the frictional force required to keep the large car on the road 65. Young's double-slit experiment is performed with a pair of without skidding is slits separated by a distance d. A screen is a distance L (A) 4F (B) 2F (C) F (D) F/2 away from the slits, and the distance from the central th maximum to the n bright fringe is x. What is the wavelength of this light? (A) nxdL (B) xd/nL (C) nL/xd (D) L/nxd Approximate AP Grading Scale AP Grade Number Correct Percentages 5 69 – 48 (100 % - 70 %) 4 47 – 38 (69 % - 55 %) 3 37 – 28 (54 % - 40 %) 2 27 – 17 (39 % - 25 %) 1 16 – 0 (24 % - 0 %) Free Response (Calculator) 1. In an experiment, students are to calculate the spring e. Describe a procedure for measuring the height h in the constant k of a vertical spring in a small jumping toy that experiment, given that the toy is only momentarily at initially rests on a table. When the spring in the toy is that maximum height. compressed a distance x from its uncompressed length Lo and the toy is released, the top of the toy rises to a maximum height h above the point of maximum compression. The students repeat the experiment several times, measuring h with objects of various masses taped to 2. Two small objects, labeled 1 and 2 in the diagram, are the top of the toy so that the combined mass of the toy and suspended in equilibrium from strings of length L. Each added objects is m. The bottom of the toy and the spring object has mass m and charge +Q. Assume that the each have negligible mass compared to the top of the toy strings have negligible mass and are insulating and and the objects taped to it. electrically neutral. Express all algebraic answers in terms of m, L, Q, , and fundamental constants. a. On the following diagram, sketch lines to illustrate a 2- dimensional view of the net electric field due to the two objects in the region enclosed by the dashed lines. a. Derive an expression for the height h in terms of m, x, k, and fundamental constants. b. Derive an expression for the electric potential at point With the spring compressed a distance x = 0.020 m in A, shown in the diagram, which is midway between each trial, the students obtained the following data for the charged objects. different values of m. m (kg) h (m) 0.020 0.49 c. On the diagram of object 1, draw and label vectors to 0.030 0.34 represent the forces on the object. 0.040 0.28 0.050 0.19 0.060 0.18 b. (1) What quantities should be graphed so that the slope of a best-fit straight line through the data points can be used to calculate the spring constant k? d. Using the conditions of equilibrium, write—but do not solve—two equations that could, together, be solved for and the tension T in the left-hand string. (2) Fill in one or both of the blank columns in the table with calculated values of your quantities, including units. c. On the axes below, plot your data and draw a best-fit 3. A metal rod of mass 0.22 kg lies across two parallel straight line. Label the axes and indicate the scale. conducting rails that are a distance of 0.52 m apart on a h (m) tabletop. A 3.0- resistor is connected across the left ends of the rails. The rod and rails have negligible resistance but 0.5 significant friction with a coefficient of kinetic friction of 0.20. There is a magnetic field of 0.80-T perpendicular to the 0.4 plane of the tabletop. A string pulls the metal rod to the right with a constant speed of 1.8 m/s. 0.3 0.2 0.1 0 10 20 30 40 50 -1 1/m ((kg ) d. Using your best-fit line, calculate the numerical value of the spring constant. a. Calculate the magnitude of the current induced in the a. Must all tensions be the same? Justify your answer. loop formed by the rod, the rails, and the resistor. -5 3 Object A has a volume of 1.0 x 10 m and a density of 3 b. Calculate the magnitude of the force required to pull 1300 kg/m . The tension in the string to which object A is the rod to the right with constant speed. attached is 0.0098 N. b. Calculate the buoyant force on object A. c. Calculate the energy dissipated in the resistor in 2.0 s. c. Calculate the density of the liquid. d. Calculate the work done pulling the rod in 2.0 s. d. Some of the liquid is now drained from the tank until only half of the volume of object A is submerged. Would the tension in the string to which object A is e. Compare your answers to parts (c) and (d). Provide a attached increase, decrease, or remain the same? physical explanation for why they are equal or unequal. Justify your answer. 6. A beam of wavelength 550 nm is incident perpendicularly -6 4. The cylinder contains 2.2 kg of water vapor initially at a onto a pair of slits. Each slit has a width w of 1.2 x 10 m, 3 5 volume of 2.0 m and an absolute pressure of 3.0 x 10 Pa. and the distance d between the centers of the slits is 1.8 x -5 This state is represented by point A in the PV diagram. 10 m. The class observes light and dark fringes on a screen that is a distance L of 2.2 m from the slits. a. Calculate the temperature of the water vapor at point A. a. Calculate the frequency of the light. The absolute pressure of the water vapor is increased at 5 constant volume to 4.0 x 10 Pa at point B, and then the volume of the water vapor is increased at constant b. Calculate the distance between two adjacent dark 3 pressure to 2.5 m at point C, as shown in the PV diagram. fringes on the screen. The entire apparatus is now immersed in a transparent fluid having index of refraction 1.4. c. What is the frequency of the light in the fluid? d. Does the distance between the dark fringes increase, decrease, or remain the same? Explain your reasoning. b. Calculate the temperature of the water vapor at point C. 7. 250 nm photon ejects an electron from a metal. The ejected electron has a de Broglie wavelength of 0.85 nm. c. Does the internal energy of the water vapor for the a. Calculate the kinetic energy of the electron. process A B C increase, decrease, or remain the same? Justify your answer. b. Assuming the kinetic energy found in (a) is maximum, calculate the work function of the metal. d. Calculate the work done on the water vapor for the process A B C. c. The 400 nm photon was created when an atom underwent an electronic transition labeled X on the energy level diagram. Which transition could generate 5. Three objects of identical mass attached to strings are the 250 nm photon? Justify your answer. suspended in a large tank of liquid, as shown.
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