8. Base your answer to the following question on the diagram below.

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1 1. A hanging plant weighing 15 newtons is suspended by two light strings of equal length. They make an angle of 30 and 60 degrees with the horizontal. What are the tensions of the 30 degree and 60 degree string respectively? A) 7.5, 7.5 B) 7.5, 7.5 C) 7.5, 7.5 D) E) A 500 newton physicist is rappelling down the side of a cliff. If the physicist swings 36.9 degrees and picks up a 20 newton rock what is the tension on the rope? A) 90 newtons B) 312 newtons C) 500 newtons D) 416 newtons E) 650 newtons 3. Two physicists are playing tug-o-war. The rope is extremely light in comparison with the 70 kg mass in the center. If the two physicists are in equilibrium and the ropes make angles 30 degrees and 60 degrees with the horizontal. Respectively, the tension on each side of the rope is A) 100 N and 300 N B) 200 N and 400 N C) 350 N and 600 N D) 500 N and 100 N E) 600 N and 300 N 4. A bowling ball of mass m is suspended by two light pieces of fishing line, equal in length. Each line makes an angle with the ceiling. What is the weight of the bowling ball if a student measures the tension in one string to be 4 newtons? A) 4 newtons B) 4 sin newtons C) 6 newtons D) 8 newtons E) 8 sin newtons 5. Which of the following is not true about a 500 newton box hanging on a massless rope in static equilibrium? A) The net force is zero B) The net acceleration is zero C) The tension in the rope is 500 newtons D) The net vertical force is zero E) The net horizontal force is 500 newtons 6. A student is hoisting a 50 newton trunk at a constant rate. He is using a uniform 10 kg cable, 25 meters long wrapped around a pulley attached to the 15 meter high ceiling. The tension in the rope at the pulley A) Is always 40 newtons B) Is always 50 newtons C) Is always 60 newtons D) Increases as the trunk is lifted E) Decreases as the trunk is lifted 7. Base your answer to the following question on the diagram below. A pendulum consists of a bob of mass A hanging from a string of non-zero mass m. Its maximum displacement is /4. What is true of the tension in the string? A) It is greatest at the top. B) It is greatest at the bottom. C) It is uniform throughout. D) It does not vary when the pendulum is put in motion. E) It is greatest when the pendulum is it its maximum amplitude.

2 8. Base your answer to the following question on the diagram below. At what point during the pendulum's motion is the tension in the string the greatest if B is the maximum displacement of the pendulum? (Note: the maximum angular displacement is less than /3.) A) at point A B) at point B C) between point A and point B D) the tension is always the same E) not enough information is given 9. Base your answer to the following question on the diagram below. Assuming the strings are massless, what is the tension T? A) 175 N B) 300 N C) 450 N D) 520 N E) 600 N 10. A ball of mass m hangs vertically from a massless string experiencing a tension T. What force is required to pull the ball out to an angle q from the vertical? A) mg sin q B) mg cos q C) mg tan q D) 2mg tan q E) mg/cos q 11. A uniform rope of weight 50 N hangs from a ceiling. A box hangs from the bottom of the rope. The ratio of tension at the top of the rope to the tension at the bottom is 3:1. What is the mass of the box? A) 100 kg B) 50 kg C) 20 kg D) 10 kg E) 2.5 kg Base your answers to questions 12 and 13 on the diagram below which shows an object of weight W is suspended from two massless strings. 12. The tension in string T 2 is A) W cos q B) W cos q C) W tan q D) W tan q E) W sin q 13. The tension in string T 1 is A) W B) W sin q C) W sin q D) W cos q E) W cos q

3 14. A uniform rope of weight 60 N hangs from a ceiling as shown above. A box of weight 90 N hangs from the rope. What is the ratio of the tension at the top of the rope to the tension at the bottom? A) B) C) 1 D) E) 15. A uniform rope of weighing 30 N hangs from a ceiling as shown above. A box of weight 50 N hangs from the rope. What is the tension in the rope? A) 50 N throughout the rope. B) 65 N throughout the rope. C) 80 N throughout the rope. D) It varies from 50 N at the bottom of the rope to 80 N at the top. E) It varies from 80 N at the bottom of the rope to 50 N at the top. 16. A box of mass 50 kg is held by two identical, vertical, and massless ropes. What is the tension in each string? A) 50 N B) 250 N C) 500 N D) 300 N E) 100 N 17. Two massless strings of equal length are used to suspend a ball as shown above. If the tension in the first string is T, what is the tension in the second string? A) Tsin B) Tcos C) T cos D) mg T E) mg Tsin 18. A 2,000 newton car is parked on a 30 degree incline. If the driver does not use the emergency brake, how much force must the transmission exert on the car? A) 1,000 newtons B) 1,700 newtons C) 2,000 newtons D) 2,300 newtons E) 4,000 newtons 19. A student wants to keep a block from falling down a frictionless ramp inclined at 53.1 degrees. If the block is to move at a constant rate how much force needs to be applied to a 50 newton block? A) 25 newtons B) 30 newtons C) 40 newtons D) 50 newtons E) 60 newtons 20. What force is required to push a block (mass m) up an inclined plane that makes an angle of q with the horizon at a constant velocity, if the coefficient of friction between the plane and the block is m? A) mg (m cos q + sin q ) B) mgm cos q C) mg (m sin q + cos q ) D) mg (m cos q + m sin q ) E) g (m cos q + m sin q )

4 Base your answers to questions 21 and 22 on the following. A block of mass M on a frictionless ramp that makes an angle of q to the horizontal. It is held at rest by a massless string which passes over a frictionless pulley and is attached to a block of mass m as shown in the diagram below. 21. The mass m is equal to A) B) C) Mtan q D) Mcos q E) Msin q 22. The normal force on the block of mass M is A) B) C) Mg D) Mgcos q E) Mgsin q 23. The top of a 50 m long inclined plane is 5 m off the ground. If a 10 kg mass is at the top of this plane, the net force it feels is most nearly A) 1 N B) 5 N C) 10 N D) 25 N E) 50 N 24. A 5.0 kg object rests on a an inclined plane that makes an angle of 30º to the horizontal. The net force felt by the object is most nearly A) 2.5 N B) 5 N C) 25 N D) 50 N E) 75 N 25. Three dogs are playing with a tennis ball. If two of the dogs are pulling with 106 degrees between them exerting a force of 20 newtons and 50 newtons, what is the magnitude of minimum force exerted by the third dog needed to keep the ball from moving? A) 20 newtons B) 30 newtons C) 50 newtons D) 60 newtons E) 70 newtons 26. In which instance is net force on the particle equal to zero? A) A feather dropped on the moon (There is no air on the moon) B) A car going from 0 to 60 miles per hour C) sky diver falling at her terminal velocity. D) A cyclist releasing the breaks and rolling down a steep incline E) A model rocket being launched from rest 27. Which of the following are necessary for an object to be in translational equilibrium I. Net velocity = 0 m/s II. Net acceleration = 0 m/s 2 III. Net force = 0 N A) I only B) III only C) I and II only D) II and III only E) I, II, and III

5 28. An object that was formerly in a state of equilibrium is no longer is such a state. Which of the following does NOT describe this situation? A) A rock initially at rest begins to slide down an inclined plane. B) A ball held in a stationary hand is dropped from a height. C) An object decelerates along a plane and comes to be at rest. D) A box at rest on the floor is placed on a shelf. E) A car traveling northat constant velocityturns left. 29. When an object is in translational equilibrium, which of the following must be zero? A) velocity B) momentum C) acceleration D) kinetic energy E) net torque 30. The weight of a 2.5 kg block on the surface of the earth is most nearly A) 2.5 N B) 6 N C) 10 N D) 25 N E) 50 N 31. A block of weight W is pushed along a horizontal surface at constant speed v by a forces F that acts at an angle. What is the magnitude of the normal force on the block? A) W Fcos B) W Fsin C) W D) W + Fsin E) W + Fcos 32. A 15 N force is applied to a 12 kg box for 6 s. The box is initially at rest. What is the speed of the box at the end of the 6 s interval? A) 1.8 m/s B) 3 m/s C) 7.5 m/s D) 15 m/s E) 30 m/s 33. A tennis player hits a 1 newton ball horizontally with a force of 5 newtons. How far does the ball travel in horizontally 2 seconds? A) 25 meters B) 50 meters C) 75 meters D) 100 meters E) 1,000 meters 34. A coin is dropped off the top of the Empire state building which is 440 meters high. The coin is kg if the coin encounters a constant resistant force of newtons. What is the acceleration of the coin when it lands? A) 5 m/s 2 B) 9 m/s 2 C) 10 m/s 2 D) 20 m/s 2 E) 30 m/s A physicist steps on a piece of gum. The gum exerts a constant non conservative force of 3 newtons as she picks up her foot. If her foot is 1 kg how much force would she have to exert to accelerate her foot vertically at 6 m/s 2? A) 15 newtons B) 18 newtons C) 28 newtons D) 22 newtons E) 25 newtons 36. A car is moving at 40 m/s. At 10 meters the driver spots a deer on the road and instantly steps on the brakes. If the car is 400 kg how much force must the breaks exert to stop the car in time? A) 0.5 newtons B) 80 newtons C) 160 newtons D) 3,200 newtons E) 32,000 newtons 37. An enthusiastic physics student takes a scale into an elevator. Before getting in the elevator the student measured his weight to be 500 newtons. Wile the elevator was moving up the 8 th floor, his weight was measured to be 600 newtons. At what rate did the elevator accelerate? A) 2 m/s 2 B) 5 m/s 2 C) 10 m/s 2 D) 15 m/s 2 E) 20 m/s 2

6 38. A wagon of mass m is pulled by a string parallel to its direction of motion. If there is a frictional force F acting on the wagon and the tension in the string is T, what is the acceleration of the wagon? A) (T F)/m B) (F T)/m C) T/m D) (F + T)/m E) (F + T)m 39. A box of mass m slides along a horizontal floor with constant velocity v. The coefficient of kinetic friction between the box and the floor is µ. What is the net force on the box? A) µmgv B) mgv C) µmv 2 D) 0 N E) µmg/v 40. How much force is required to vertically lift an object of mass m with acceleration g? A) mg B) 2mg C) mg 2 D) 2mg 2 E) m/g 41. Block A of mass m is at rest on a horizontal, frictionless surface. Block B of mass m is moving on a frictionless horizontal surface at constant velocity v. When a force F is applied to both blocks in the direction of B's motion, the resulting acceleration of Block B relative to Block A is A) less, and in a different direction B) less, and in the same direction C) greater, and in a different direction D) greater, and in the same direction E) the same 42. An object with mass m is at rest on a frictionless horizontal surface on Earth. If a horizontal force F is applied to this object, its resulting acceleration is a. An identical object of mass m is at rest on a frictionless horizontal surface on Planet Y, which has a gravitational acceleration of 0.1g. If this mass is pushed on the same surface with the same horizontal force F, what will be its resulting acceleration? A) 0.1a B) 0.2a C) 0.5a D) a E) 10a 43. A cat that weighs 50 N when at rest on Earth stands on a scale in an elevator moving upward at a constant velocity of 10 m/s. What does the scale read? A) 0 N B) 50 N C) 100 N D) 200 N E) 1000 N 44. A student that has a mass of 100 kg is standing on a scale in an elevator car. The elevator is accelerating downward at 5 m/s 2 in the Earth's gravitational field. The reading on the scale in the elevator is most nearly A) 150 N B) 500 N C) 1000 N D) 1500 N E) 50 N 45. A dog that weighs 500 N at rest on the Earth's surface is standing on a scale on the floor of an elevator. The elevator is accelerating upward in the Earth's gravitational field at a rate of 9.8 m/s 2. What does the scale read? A) 0 N B) 250 N C) 500 N D) 1000 N E) 2000 N 46. An elevator is moving upwards at a constant velocity of 5 m/s. What is the net acceleration the elevator experiences? A) 0 m/s 2 B) C) D) g E) 2g 47. A force F gives an object with a mass m an acceleration a. If this force F is applied to an object of mass m, what would the acceleration be? A) a B) a C) 2a D) 4a E) 8a

7 48. Base your answer to the following question on the following information. A proton with a mass of kg is accelerated from rest for a time of 10-8 s by a uniform electric field that exerts a force of N on the proton. The distance over which the proton accelerated is most nearly A) m B) m C) m D) m E) m Base your answers to questions 49 and 50 on the following situation. A ball of mass m is dropped down through the air in a gravitational field. The magnitude of the force of air resistance is bv 2 where b is a positive constant. 49. What is the terminal speed of the ball? A) B) C) D) E) 50. The magnitude of the acceleration of the ball at any time is A) g b B) g bv 2 /m C) g + bv 2 /m D) g/b E) bv 2 + g Base your answers to questions 51 and 52 on the picture below, which represents a frictionless system accelerated by a force of magnitude F. The tension in the string connecting blocks A and B is F. 51. What is the tension in the string connecting blocks B and C? A) F B) F C) F D) F E) 2F 52. If blocks B and C each have a mass m, what is the mass of block A? A) m 3 B) m 2 C) m D) 2m E) 3m 53. In the frictionless system shown above, all blocks have the same mass, and the entire system is accelerated by an applied force of magnitude F. What is the tension in the cord between blocks B and C? A) F B) F C) F D) F E) 2F 54. A wagon is pulled up a 36.9 degree incline at a constant rate with a 50 newton force. If a 12 newton force wind blows behind the wagon, what is the increase in acceleration? A) 3 m/s 2 B) 4 m/s 2 C) 36 m/s 2 D) 48 m/s 2 E) 64 m/s A motorcyclist comes to a red light on a hill while traveling at 30 m/s. The incline is 30 degrees and he is facing down hill. How much force would the breaks need to exert to stop from 20 meters away if the combined weight of cyclist and cycle is 1,200 newtons? A) 44 newtons B) 440 newtons C) 2,100 newtons D) 3,300 newtons E) 33,000 newtons 56. A greased pig starts at rest from the top of a frictionless slide a height 25 m above his mud pit. If the bottom section of the slide is 5 m above the pit and is parallel to the ground, at what distance from the bottom of the slide will the pig hit the mud? A) 10 m B) 15 m C) 20 m D) 28 m E) 36 m

8 Base your answers to questions 57 through 59 on the following diagram, which shows a block that starts at the top of a frictionless ramp and slides down. Base your answers to questions 60 through 62 on the following diagram, which shows a block sliding down a frictionless ramp. The block starts at the top of the ramp and takes 4 s to slide to the bottom of the ramp. 57. If the mass of the block is 5 kg, how much work is done by gravity as the block slides down the full length of the incline? A) 10 J B) 100 J C) 200 J D) 1000 J E) 2000 J 58. With what speed will the block reach the bottom if it was released from rest at the top? A) 10 m/s B) 20 m/s C) 25 m/s D) 30 m/s E) 40 m/s 59. How long does it take to block to slide to the bottom of the ramp? A) 4 s B) 8 s C) 10 s D) 16 s E) There is insufficient information to answer the question. 60. If the coefficient of kinetic friction between the block and the incline is 0.4, the work that the normal force does on the block during the slide is A) 0 J B) 20 J C) 240 J D) 550 J E) 700 J 61. The speed of the block when it reaches the bottom of the ramp is most nearly A) 4 m/s B) 8 m/s C) 14 m/s D) 20 m/s E) 40 m/s 62. How high is the top of the ramp? A) 5 m B) 10 m C) 20 m D) 25 m E) 40 m 63. A train contains three cars, accelerating at a. If the three cars all have the same mass, what is the mass of one car if the engine exerts a force F? A) B) C) D) E) 64. Two massless strings of equal length support a hammer, making 30 degree angles with the ceiling. The tension on one of the strings is 10 newtons. When one string is cut, what is the initial horizontal acceleration of the hammer? A) B) C) D) E)

9 65. An astronaut on the moon drops a coin where the acceleration of gravity is g, where g is a constant. Which of the following is true about the net force experienced by the coin? A) The force decrease as the coin approaches the surface B) The force increases as the coin approaches the surface C) The net force is zero D) The force is greatest in the middle of its path and least at the beginning and end E) The force is constant 66. An object moves through space at a constant velocity. Which of the following cannot be true? A) It is accelerating centripetally. B) The sum of all force on the object is zero. C) It is in dynamic equilibrium. D) The net work done on the object is zero. E) Forces are acting on the object. Base your answers to questions 67 and 68 on the graph below which plots the net force on an object versus time. 67. If at t = 1 the acceleration of the object is 2.5 m/s 2, what is the mass of the object? A) 2 kg B) 4 kg C) 6 kg D) 8 kg E) 10 kg 68. At how many points does the object achieve equilibrium? A) 0 B) 1 C) 2 D) 3 E) Which graph best represents the relationship between mass and acceleration due to gravity for objects near the surface of the Earth? A) B) C) D) 70. Three forces act upon an object. The vector sum of these forces is zero. Which of the following must be true? I. The object's velocity is zero. II. The object's acceleration is zero. III. The object is in translational equilibrium. A) II only B) III only C) I and II only D) II and III only E) I, II, and III only 71. Four forces act on an object. If the net acceleration of the object is zero, which of the following must be true? I. The forces must have equal magnitude. II. The forces must act in the same plane. III. The vector sum of all the forces must be zero. A) II only B) III only C) I and II only D) II and III only E) I, II, and III 72. If L, M and T denote the dimensions of length, mass, and time, respectively, what are the dimensions of force? A) L/MT B) MT/L C) ML/T D) ML/T 2 E) ML 2 /T An object is acted upon by four forces, each of magnitude 20 N and its resulting acceleration is 10 m/s 2. Which of the following could be the mass of the object? A) 5 kg B) 10 kg C) 12 kg D) 20 kg E) 25 kg

10 74. An object with a mass of 2 kg is acted upon by 4 forces, each with a magnitude of 20 N. Which of the following could NOT be the resulting acceleration of the object? A) 0 m/s 2 B) 10 m/s 2 C) 20 m/s 2 D) 37 m/s 2 E) 45 m/s In the figure above, two blocks are connected via a massless string over a massless, frictionless pulley. If the acceleration of the blocks once they are released from rest is 0.6g, the coefficient of kinetic friction between the block of mass m and the table is A) 0.2 B) 0.4 C) 0.6 D) 0.8 E) In the above diagram, blocks of mass m and M (M > m) are hung by a massless string over a massless, frictionless pulley. The tension in the string is A) (M + m)g B) (M m)g C) gmm M + m D) 2gMm M + m E) gmm M m 76. In the figure above, the coefficient of kinetic friction between the block of mass m and the table is 0.5. If the pulley is massless and frictionless, determine the acceleration of the blocks if they are released from rest. A) 0.5g B) 0.5g/3 C) 0.6g/3 D) 0.6g E) 0.7g

11 80. In which of the following situations is an object accelerated? 78. Blocks of mass M and m are connected by a massless string across a massless, frictionless pulley, as shown in the above diagram. Which of the following properly represents the acceleration of the block with mass M when released from rest? A) Mg m B) mg M + m C) Mg M + m D) (M + m)g M m E) (M m)g M + m 79. If object X has half the mass of object Y, then which statements below are true? I. On the moon, X experience half the gravitational force that Y experiences. II. On the moon the acceleration due to gravity for object X is half of that for object Y. III. When both have the same speed and are in the same circular orbit, X experiences half the centripetal force of Y. A) I only B) II only C) I and II only D) I and III only E) I, II, and III I. It moves in a straight line with constant speed. II. It moves in a circle with constant speed. III. It moves as a projectile in a uniform gravitational field A) I only B) III only C) I and III only D) II and III only E) I, II, and III Base your answers to questions 81 and 82 on the diagram below which shows a box of mass m being pulled across a rough horizontal floor by a force of magnitude T at an angle. The coefficient of friction between the box and the floor is m. 81. The normal force on the box has magnitude A) mg + Tsin q B) mg Tsin q C) mg + Tcos q D) mg Tcos q E) mg 82. The acceleration of the block has magnitude A) Tsinq + m(mg+tsinq) B) Tsinq m(mg+tsinq) m C) Tcosq m(mg Tsinq) m D) (Tcosq m(mg+tsinq))/m E) Tsinq + m(mg Tsinq) 83. A shooter on ice fires a gun. She experiences recoil of 2 m/s 2 when the bullet is fired with a force 100 newtons. What is the mass of the shooter? A) 10 kg B) 20 kg C) 50 kg D) 80 kg E) 100 kg

12 84. A person grabs their belt and pulls upward with a force of 40 newtons. If the person weighs 500 newtons what is the net force experienced by the person? A) 0 newtons B) 0.02 newtons C) 12.5 newtons D) 460 newtons E) 540 newtons 85. The frictional force on each twin is 50 newtons. If each twin is 500 newtons and they are pushing off each other then how much force can they exert before they slip? A) 25 newtons B) 50 newtons C) 100 newtons D) 1,000 newtons E) 5,000 newtons 86. Two students in frictionless rolling office chairs push off each other with force F. If their masses are m and 2m then respectively the acceleration they experience are A) and B) and C) and D) and A) 25 newtons B) 50 newtons C) 70 newtons D) 90 newtons E) 100 newtons E) and 87. A 100 newton box sits on a frictionless 60 degree incline. If the box is kept still by a rope, how much force does the incline exert on the box? 88. A man is trying to push his car across a frozen lake. If the car is 600 kg, the man is 70 kg, and the man pushes with a force of 50 newtons how fast will the man accelerate? A) 0.08 m/s 2 B) 0.7 m/s 2 C) 1.4 m/s 2 D) 5 m/s 2 E) 12 m/s A person is accelerating 2 blocks of different masses by sliding them end to end with a 10 newton force. Which of the following statements is true? A) Both blocks are accelerating at the same rate B) The heavier mass is accelerating at a faster rate C) The lighter mass is accelerating at a faster rate D) The net force is 0 E) The velocity of the lighter block is constant 90. A 100 kg cannon fires a 20 kg cannonball on a sheet of ice. If the force exerted on the canon ball is 100 newtons, what is the acceleration experienced by the cannon? A) 1 m/s 2 B) 5 m/s 2 C) 50 m/s 2 D) 100 m/s 2 E) 500 m/s Which of the following are always true about two ice skaters of different mass pushing off each other? A) They both experience the same final velocity B) The both experience the same acceleration C) They both travel the same distance D) They both experience the same force E) They experience unequal forces 92. On a frozen pond a hunter fires his rifle. The 1 gram bullet reaches 300 m/s in 5 seconds. If the hunter is 60 kg what acceleration does he experience? A) m/s 2 B) m/s 2 C) 0.01 m/s 2 D) 0.06 m/s 2 E) 60 m/s A golfer swings a golf club and hits a ball. Which of the following best explains why the effects of the collision on the club are difficult to observe? I. The club's mass is large compared to that of the ball. II. The club's initial momentum is large compared to the impulse imparted to it by the collision. III. The collision causes only the ball to accelerate, not the club. A) I only B) III only C) I and II only D) II and III only E) I, II, and III

13 94. A golfer swings a club and hits a golf ball. Which of the following best describes the collision between the club and the ball? A) The club exerts a force on the ball that causes it to accelerate for a short period of time. B) The club exerts a force on the ball that cause it to accelerate through the air. C) The club and the ball exert equal and opposite forces on each other, but only ball accelerates due to this force. D) The club and the ball exert equal and opposite forces on each other and both objects experience an acceleration. E) The momentum of the club is the same before and after it hits the ball. 95. How can Newton's Third Law be explained with an object experiencing fluid friction? A) The fluid exerts a force on the object that is an isolated force. B) The fluid exerts a force on the object and the object exerts an equal force on the molecules of the fluid. C) The force does work to create heat energy. D) The object decelerates as the sum of all forces is negative. E) The object's motion is slowed because there is a force exerted on it in a direction opposite to its motion. 96. A physics teacher pushes against the wall with a force of 100 N. What is the magnitude of the force exerted on the physics teacher by the wall. A) 0 N B) 100 N C) Depends on the mass of the teacher D) Depends on the mass of the wall E) Depends on both the mass of the teacher and the mass of the wall 97. The pain experienced when kicking a large boulder can be explained by A) Newton's First Law of Motion B) Newton's Second Law of Motion C) Newton's Third Law of Motion D) Faraday's Law E) Lenz's Law 98. A woman of mass M standing on an ice rink (friction negligible) fires a bullet of mass m from a gun parallel to the surface of the rink. The bullet accelerates at a rate of a, leaving the gun at velocity v and hitting the surface of the rink after time t. What is the magnitude of the woman's acceleration? A) vt/a B) ta/m C) vtm/am D) 2vm/M E) ma/m 99. Block A of mass 2M rests upon Block B of mass M. What is the ratio of the normal force exerted by Block B on Block A to the force of gravity exerted on the Block A-Block B system? A) 5:2 B) 3:2 C) 1:1 D) 2:3 E) 2: According to Newton's Third Law, A) for every action there is a weaker, and opposite, reaction B) for every action there is an equal, but delayed, reaction C) for every action there is an equal, and similar, reaction D) for every action there is an equal, but opposite, reaction E) for every action there is a weaker, but opposite, reaction Base your answers to questions 101 and 102 on the information below. A child of mass 60 kg is standing on a frictionless surface. The child throws a ball of mass 5 kg with a force of 30 N What is ratio of the force felt by the child to the force felt by the ball? A) 12:1 B) 6:1 C) 1:1 D) 1:6 E) 1: What is the magnitude of the child's acceleration over the surface? A) 0.25 m/s 2 B) 0.5 m/s 2 C) 0.75 m/s 2 D) 1 m/s 2 E) 1.25 m/s 2

14 Base your answers to questions 103 and 104 on the information below. A cannon of mass 55 kg fires a projectile, exerting a force of 150 N on the object. The cannon rests on a surface with a coefficient of static friction of What is the minimum amount of force the cannon must exert on the object for it to overcome the force of friction? A) 150 N B) 220 N C) 280 N D) 350 N E) 475 N 104. What happens to the cannon after it fires? A) The cannon moves back 15 m before coming to rest. B) The cannon moves back 30 m before coming to rest. C) The cannon moves back 0.15 m before coming to rest D) The cannon moves back 0.3 meters before coming to rest. E) The cannon does not move A rocket engine acquires motion by ejecting hot gases in the opposite direction. This is an example of the law of A) conservation of heat B) conservation of energy C) conservation of linear momentum D) conservation of mass E) conservation of angular momentum 106. Two skaters, one of mass 100 kg, the other of mass 50 kg are on a frozen pond (negligible friction). If the heavier person pushed the lighter one with a force F, the ratio of the magnitude of the acceleration of the lighter skater to that of the heavier is A) 1:4 B) 1:2 C) 1:1 D) 2:1 E) 4: Two skaters, one of mass 75 kg, the other of mass 50 kg, stand next to each other on ice (negligible friction). If the heavier skater pushes the lighter with a force F, the ratio of the force felt by the lighter to the force felt by the heavier is A) 1:3 B) 2:3 C) 1:1 D) 3:2 E) 3: There are two forces acting upon an object at rest on a horizontal floor: the pull of gravity and the normal force from the floor. These two forces A) have different magnitudes and the same direction B) have different magnitudes and opposite directions C) have the same magnitude and the same direction D) have the same magnitude and opposite directions E) have the same magnitude and are perpendicular 109. A force of magnitude F pushes two blocks on a frictionless surface. What is the force the 4 kg block exerts on the 2 kg block? A) 4F B) 2F C) D) E) 110. A car drives along a curved track. The frictional force exerted by the track on the car is A) greater than the frictional force exerted by the car on the track B) directed radially outward C) opposite in direction to the frictional force exerted by the car on the track D) zero if the car's speed is constant E) dependent on the radius of the track 111. The coefficient of static friction between an arrow and the surface of a crossbow is If the bow is held horizontally what is the minimum force needed to move a newton arrow? A) newtons B) newtons C) newtons D) 0.25 newtons E) 4 newtons

15 112. A student uses a weight hanger and string to apply newton weights to a cup in the horizontal direction. If the cup is 3 newtons and takes 3 weights to cause motion what is the coefficient of static friction? A) B) C) 0.03 D) 0.1 E) The coefficient of static friction between a 200 newton pile of cinder blocks and the ground is A student trying to move the pile connects a frictionless pulley system to a rafter 3 meters high and stands 4 meters away pulling straight down. How much force is needed to move the pile? A) newtons B) newtons C) 2 newtons D) newtons E) newtons 114. The coefficient of static friction between an incline of adjustable height and a 20 newton brick is What is the maximum angle of the incline which can keep the brick from sliding? A) 0 degrees B) Arctan(0.005) C) 45 degrees D) Arctan(5,000) E) 90 degrees 115. The coefficient of static friction between the road and the tires on a 2,500 newton car is How fast can the car decelerate without skidding? A) 0.04 m/s 2 B) 0.4 m/s 2 C) 4 m/s 2 D) 10 m/s 2 E) 100 m/s Compared to the force of friction felt by an object which has a force exerted on it sliding on a rough surface, the force of friction felt by the object which has an equal force exerted on it while remaining at rest on the same surface A) is the same B) is greater C) is lesser D) depends on the nature of the object and the surface E) virtually zero 117. What is the work done by friction on an 10 N object that is initially at rest on a surface with a coefficient of static friction of 0.8 when the object is pushed by a 7 N force for 10 s? A) 0 J B) 10 J C) 20 J D) 70 J E) 80 J 118. An object of mass m is placed on an inclined plane that makes an angle of q with the horizontal. When released, the object remains stationary. The coefficient of static friction between the object and the plane is m. Which of the following must be true? A) m cos q ³ sin q B) m sin q ³ cos q C) m sin q =.5 cos q D) m cos q < sin q E) m cos q sin q 119. Two crates are stacked on top of each other on a horizontal floor. The coefficient of static friction between Box A and Box B is 0.6. The coefficient of static friction between Box A and the floor is 0.2. A force of 100 N is applied parallel to the floor on Box B. The boxes move together along the floor. The ratio of the mass of Box A to Box B is possibly A) 5:1 B) 5:2 C) 4:1 D) 3:1 E) 1: Two boxes, each weighing 900 N are stacked on a horizontal floor. Box A is on the bottom, Box B is on the top. The coefficient of static friction between Box A and the floor is 0.3. A worker applies a force of 600 N to Box B parallel to the floor, and the stack moves together along the floor. Which of the following could be the coefficient of static friction between Box A and Box B? A) 0.7 B) 0.5 C) 0.4 D) 0.3 E) 0.1

16 121. Block A with mass m is placed on a horizontal surface. The static coefficient of friction between A and the surface is 0.6. The magnitude of the force necessary to push it across the surface at a constant velocity is F1. Block B, also of mass m is placed on top of the first block. The static coefficient of friction between A and B is 0.5. The force necessary to push this stack across the floor at constant velocity, F2, is greater than F1 because A) the force of friction on Block B is greater B) the coefficient of friction between Block A and the floor is greater C) the weight of Block A is greater D) the force of the floor on Block A is greater E) of the additional frictional force between Block A and Block B 122. A box weighing 100 N is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is 0.5, and the coefficient of kinetic friction is If the crate is pushed with a force of 20 N parallel to the floor, which of the following is true? A) The crate will remain stationary, due to the static friction force of 50 N which opposes the intended motion. B) The crate will remain stationary, due to the static friction force of 20 N which opposes the intended motion. C) The crate will accelerate across the floor at 3 m/s 2. D) The crate will accelerate at until it reaches 3 m/s then remain traveling at that constant velocity. E) The crate will accelerate at 3 m/s 2, then its acceleration will increase to 5 m/s A 50 kg mass is placed on a inclined plane that makes an angle of 37º with the horizontal. When released, the mass remains motionless. The coefficient of static friction between the mass and the plane is at least A) 0.1 B) 0.2 C) 0.4 D) 0.5 E) A 20 kg block is held at rest on a ramp that makes an angle of 30º with the horizontal. The coefficient of static friction between the block and the ramp is 0.7 and the coefficient of kinetic friction is 0.6. If the block is released, it will A) remain stationary B) begin to accelerate down the ramp, then decelerate and stop C) accelerate down the ramp D) move down the ramp with constant velocity E) accelerate down the ramp until it reaches a terminal velocity, then remain traveling at that constant velocity 125. A 3 kg block is supported on a 60 incline by a string as shown above. If the coefficient of static friction is 1.0, the tension in the string is most nearly A) 5.3 N B) 10.8 N C) 15 N D) 25.5 N E) 30 N

17 Base your answers to questions 126 through 128 on the picture below which shows a 3 kg block sliding 50 m down a frictionless inclined plane dropping a distance of 30 m What is the magnitude of the normal force of the plane on the block? A) 5 N B) 8 N C) 16 N D) 24 N E) 30 N 127. What is the magnitude of the acceleration for the block? A) 3 m/s 2 B) 4 m/s 2 C) 6 m/s 2 D) 8 m/s 2 E) 10 m/s What is the minimum coefficient of static friction needed to prevent the block from moving? A) 1/3 B) 3/5 C) 3/4 D) 4/5 E) 5/ A 500 newton cyclist is skidding down a hill at a constant 40 m/s if the coefficient of kinetic friction is 0.1, what is the angle of the incline? A) Arctan(1/10) B) Arctan(10) C) Arctan(250) D) Arccos(250) E) Arccos(1/10) 130. If on earth an object has a weight W and coefficient of friction on a horizontal plane, what would be the frictional force on a planet with gravity, g? A) u W B) u W C) u W D) 2 u W E) 4 u W 131. A 500 newton worker is pulling a 500 newton crate on a rope with a force of 50 newtons at a constant velocity. If the coefficient of friction for the worker is 0.05 and the coefficient for the crate is 0.04 what is the acceleration of the worker? A) 0.01 m/s 2 B) 0.1 m/s 2 C) 1 m/s 2 D) 2 m/s 2 E) 5 m/s Which of the following is most efficient for a student sliding a rock on a horizontal surface with a coefficient of friction of 0.04? A) Pushing upwards at 45 degrees B) Pushing upwards at 60 degrees C) Pushing upwards at 30 degrees D) Pushing horizontally E) Pushing upward at 90 degrees 133. The coefficient of kinetic friction between the highway and a car s tires are 0.1. The 3,000 newton car s tires lock up. How far will it skid if it was going 30 m/s? A) 0.2 meters B) 10.5 meters C) 45 meters D) 450 meters E) 5,000 meters 134. A 3 kg sled is pulled across a horizontal surface with a force of 30 N. The coefficient of friction between the surface and the sled is 0.2. What is the sled's acceleration? A) 4 m/s 2 B) 8 m/s 2 C) 10 m/s 2 D) 12 m/s 2 E) 15 m/s It requires P power to move an object of mass m at a constant velocity v on a particular planet. The coefficient between the surface of the planet and the object is m.. What is the acceleration due to gravity on this planet? A) P/mvm B) m/pv C) m/mvp D) Pm/mv E) mv/mp 136. An object traveling at 16 m/s enters a frictional area. It comes to rest after a time of 4 s. The coefficient of friction of the frictional area is A) 0.3 B) 0.4 C) 0.5 D) 0.9 E) 1.6

18 137. A 125 kg woman pushes a 75 kg couch across a floor at a constant velocity. The coefficient of kinetic friction between the floor and the couch is 0.6. She is capable of produce 2250 W of power. The maximum possible velocity of the couch is most nearly A) 50 m/s B) 25 m/s C) 5 m/s D) 3 m/s E) the couch will not move 138. A car traveling at 25 m/s slams its brakes leaving skids marks along a distance 125 m as it comes to rest. The coefficient of friction between the tires and the road is A) 5 B) 2.5 C) 1 D) 0.4 E) What is the power necessary to push a box of mass m with constant velocity v across a horizontal floor, if the coefficient of friction between the box and the floor is µ? A) µmv B) mgv C) v/µmg D) µmgv E) µmg/v 140. An object of mass m is sliding on a horizontal surface at constant velocity v. If the coefficient of kinetic friction between the object and the surface is µ, which of the following best describes the force F being applied to the object? A) of magnitude µmg, in the direction of v. B) of magnitude µmg, in the direction opposite v. C) of magnitude µmgv, normal to the surface. D) of magnitude µmg, but the direction cannot be determined. E) Not enough information is provided to determine the magnitude or direction An object is being pushed along a horizontal surface by a force of 60 N with an acceleration of 4 m/s 2. The coefficient of kinetic friction between the object and the surface is 0.1. The mass of the object is most nearly A) 6 kg B) 12 kg C) 20 kg D) 30 kg E) 60 kg 142. A 30 N block is being pulled along a horizontal surface with an acceleration of 6 m/s 2 by a rope. The coefficient of kinetic friction between the block and the surface is 0.5. What is the force applied by the rope? A) 3 N B) 15 N C) 30 N D) 33 N E) 66 N 143. An 40 kg object is being pushed along a surface at a constant velocity by a force of 80 N. What is the coefficient of kinetic friction between the object and the surface? A) 0.1 B) 0.2 C) 0.25 D) 0.4 E) A toboggan of mass 10 kg is pulled by a rope at an angle of 60 relative to the ground with a magnitude of 20N. The sled moves with constant velocity. What is the coefficient of kinetic friction between the toboggan and the ice? A) 0.10 B) 0.20 C) 0.25 D) 0.30 E) Two blocks of the same material and equal mass are pulled by a force F on a rough surface. Which statement is false? A) The coefficient of kinetic friction is the same in each case. B) A force of the same magnitude is needed to keep each block moving. C) A force of the same magnitude was required to start each block moving. D) The magnitude of the force of kinetic friction is greater for the block on the right. E) The normal force exerted on the blocks by the surface is the same for both blocks An object of mass 10 kg moving with a velocity of 30 m/s enters an area with friction. The coefficient of kinetic friction is 0.2. The time it will take for the object to stop moving is most nearly A) 6.00 s B) 7.5 s C) 15.3 s D) 22.5 s E) 30 s

19 Base your answers to questions 147 and 148 on the picture below, which represents a plane 10 m in length with a coefficient of kinetic friction of 0.2, inclined at an angle of 53º. A block of weight 30 N is placed at the top of the plane and allowed to slide down The magnitude of the frictional force exerted on the block by the plane is A) 1.5 N B) 1.8 N C) 3.0 N D) 3.6 N E) 4.5 N 149. A horizontal force of 15 N is used to push a 2 kg block along a table top that has a coefficient of friction of What is the acceleration of the block? A) 3 m/s 2 B) 6 m/s 2 C) 7.5 m/s 2 D) 8.5 m/s 2 E) 10 m/s The magnitude of the normal force exerted on the block by the plane is most nearly A) 15 N B) 18 N C) 24 N D) 30 N E) 50 N

20 Answer Key AP Force Review C 37. A 73. A 109. D 2. E 38. A 74. E 110. C 3. C 39. D 75. C 111. A 4. E 40. B 76. A 112. A 5. E 41. E 77. D 113. D 6. E 42. D 78. E 114. B 7. A 43. B 79. D 115. B 8. A 44. B 80. D 116. B 9. D 45. D 81. B 117. A 10. C 46. A 82. C 118. A 11. E 47. D 83. C 119. E 12. C 48. C 84. A 120. A 13. C 49. B 85. B 121. D 14. E 50. B 86. A 122. B 15. D 51. A 87. B 123. E 16. B 52. D 88. B 124. A 17. C 53. A 89. A 125. B 18. A 54. B 90. A 126. D 19. C 55. D 91. D 127. C 20. A 56. C 92. A 128. C 21. E 57. D 93. C 129. A 22. D 58. B 94. D 130. B 23. C 59. A 95. B 131. B 24. C 60. D 96. B 132. D 25. C 61. D 97. C 133. D 26. C 62. C 98. E 134. B 27. D 63. E 99. D 135. A 28. C 64. D 100. D 136. B 29. C 65. E 101. C 137. C 30. D 66. A 102. B 138. E 31. D 67. B 103. B 139. D 32. C 68. E 104. E 140. A 33. D 69. D 105. C 141. B 34. B 70. D 106. D 142. D 35. C 71. B 107. C 143. B 36. E 72. D 108. D 144. A

21 Answer Key AP Force Review D 146. C 147. B 148. D 149. B