45˚

Force AP Physics Multiple Choice Name ____________________

1. In the situation below, what is the tension in string 1? a. 69.3 N b. 98 N c. 138.6 N d. 147.6 N e. 1.55 N

2. Two masses, M and m, are hung over a massless, frictionless pulley as shown below. If M > m, what is the downward acceleration of mass M?

a. g b. (M−m )gM+m

c. (Mm )g d. MmgM+m e. Mmg

3. A 0.25 kg mass is attached to a string and swung in a vertical circle whose radius is 0.75 m. At the bottom of the circle, the mass is observed to have a speed of 10 m/s. What is the magnitude of the tension in the string at that point?

2

1

5 kg

F = 20 N

a. 2.45 N b. 5.78 N c. 22.6 N d. 35.7 N e. 44.7 N 4. A car and driver have a combined mass of 1000 kg. The car passes over the top of a hill that has

a radius of curvature equal to 10 m. The speed of the car at that instant is 5 m/s. What is the force of the hill on the car as it passes over the top?

a. 7300 N up b. 7300 N down c. 12,300 N up d. 12,300 N down

e. 0 N

5. A hockey puck with a mass of 0.3 kg is sliding along ice that can be considered frictionless. The puck’s velocity is 20 m/s. The puck now crosses over onto a floor that has a coefficient of kinetic friction equal to 0.35. How far will the puck travel across the floor before it stops?

a. 3 m b. 87 m c. 48 m d. 92 m e. 58 m

6. A spring with a stiffness constant k = 50 N/m has a natural length of 0.45 m. It is attached to the top of an incline that makes a 30˚ angle with the horizontal. The incline is 2.4 m long. A mass of 2 kg is attached to the spring, causing it to be stretched down the incline. How far down the incline does the end of the spring rest?

a. 0.196 m b. 0.45 m c. 0.646 m d. 0.835 m e. 1.2 m

7. A 20 N force is pushing two blocks horizontally along a frictionless floor. What is the force that the 8 kg mass exerts on the 2 kg mass?

a. 4 N b. 8 N c. 16 N d. 20 N e. 24 N

F = 20 N4 kg

8. A force of 20 N acts horizontally on a mass of 10 kg being pushed up a frictionless incline that makes a 30˚ angle with the horizontal. The magnitude of the acceleration of the mass up the incline is equal to

a. 1.9 m/s2 b. 2.2 m/s2 c. 3.17 m/s2 d. 3.87 m/s2 e. 4.3 m/s2

Label the diagram

9. According to the diagram, what is the tension in the connecting string if the table is frictionless? a. 6.4 N b. 13 N c. 19.7 N d. 25 N e. 32 N

10. A mass, M, is released from rest on an incline that makes a 42˚ angle with the horizontal. In 3 s, the mass is observed to have gone a distance of 3 m. What is the coefficient of kinetic friction between the mass and the surface of the incline?

a. 0.8 b. 0.7 c. 0.6 d. 0.5 e. 0.3

2 kg

11. Which of the following are units for the spring constant k?

a.kgm2

s2 b. kgs2 c.

kgms d.

kgs2

e. kgm2

s

12. A 2.0 kg cart is given a shove up a long, smooth 30 degree incline. If the cart is traveling 8 m/s after the shove, how much time elapses until the block returns to its initial position?

a. 1.6 s b. 3.2 s c. 4.0 s d. 6 s e. 8 s

13. A car slides up a frictionless inclined plane. How does the normal force of the incline on the car compare with the weight of the car?

a. The normal force must be equal to the car’s weight.b. The normal force must be less than the car’s weight.c. The normal force must be greater than the car’s weight.d. The normal force must be zero.e. The normal force could have any value relative to the car’s weight.

14. In the diagram above, a 1 kg cart and a 2 kg cart are connected by a rope. The spring scale reads 10 N. What is the tension in the rope connecting the two carts? Neglect any friction.

a. 30 N b. 10 N c. 6.7 N d. 5 N e. 3.3 N

15. The velocity time graph below represents the motion of a 5 kg box. The only force applied to this box is a person pushing. Assuming that the box is moving to the right, what is the magnitude and direction of the force applied by the person pushing?

a. 2 N, right b. 2 N, left c. 0.4 N, right d. 0.4 N, left e. 12.5 N, left

16. A book is lying at rest on a table. The book will remain there at rest because:a. there is a net force but the book has too much inertia.b. there are no forces acting on it at allc. it does move, but too slowly to be seend. there is no net force on the booke. there is a net force, but the book is too heavy to move

17. A hockey puck slides on ice at constant velocity. What is the net force acting on the puck?a. more than its weight.b. equal to its weightc. less than its weight but more than zerod. depends on the speed of the pucke. zero

18. You put your book on the bus seat next to you. When the bus stops suddenly, the book slides forward off the seat. Why?

a. a net force acted on it.b. no net force acted on itc. it remained at restd. it did not move, but only seemed toe. gravity briefly stopped acting on it

4

2

0 5 10 t(s)

v(m/s)

19. You kick a smooth flat stone out on a frozen pond. The stone slides, slows down and eventually stops. You conclude that:

a. the force pushing the stone forward finally stopped pushing on itb. no net force acted on the stonec. a net force acted on it all alongd. the stone simply ran out of steame. the stone has a natural tendency to be at rest

20. Consider a cart on a horizontal frictionless table. Once the cart has been given a push and released, what will happen to the cart?

a. slowly come to a stopb. continue with constant accelerationc. continue with decreasing accelerationd. continue with constant velocitye. immediately come to a stop

21. What would have to be done to the cart in order to have it continue with constant nonzero acceleration?

a. push the cart harder before releaseb. push the cart longer before releasec. push the cart continuouslyd. change the mass of the carte. it is impossible to do that

22. A very large truck sits on a frozen lake. Assume there is no friction between the tires and the ice. A fly suddenly smashes against the front window. What will happen to the truck?

a. it is too heavy, so it just sits thereb. it moves backward at constant speedc. it accelerates backwardd. it moves forward at constant speede. it accelerates forward

23. From rest, we step on the gas of our Ferrari, providing a force F for 4 seconds, speeding it up to a final speed v. If the applied force were only ½ F , how long would it have to be applied to reach the same final speed?

a. 16 s b. 8 s c. 4 s d. 2 s e. 1 s

24. From rest, we step on the gas of our Ferrari, providing a force F for 4 seconds. During this time, the car moves 50 m. If the same force would be applied for 8 seconds, how much would the car have traveled during this time?

a. 250 m b. 200 m c. 150 m d. 100 m e. 50 m

25. We step on the brakes of our Ferrari, providing a force F for 4 seconds. During this time, the car moves 25 m, but does not stop. If the same force would be applied for 8 seconds, how far would the car have traveled during this time?

a. 100 m b. 50 m < x < 100 m c. 50 m d. 25 m < x < 50 m e. 25 m

26. From rest, we step on the gas of our Ferrari, providing a force F for 40 m, speeding it up to a final speed 50 km/hr. If the same force would be applied for 80 m, what final speed would the car reach?

a. 200 km/hr b. 100 km/hr c. 90 km/hr d. 70 km/hr e. 50 km/hr

27. A force F acts on mass M for a time interval T, giving it a final speed v. If the same force acts for the same time on a different mass 2M, what would be the final speed of the bigger mass?

a. 4 v b. 2 v c. v d. ½ v e. ¼ v

28. A force F acts on mass m1 , giving acceleration a1 . The same force acts on a different mass m2

giving acceleration a2 = 2a1. If m1 and m2 are glued together and the same force F acts on this combination, what is the resulting acceleration?

a. ¾ a1 b. 3/2 a1 c. ½ a1 d. 4/3 a1 e. 2/3 a1

29. What can you say about the force of gravity Fg acting on a stone and a feather?a. Fg is greater on the featherb. Fg is greater on the stonec. Fg is zero on both due to vacuumd. Fg is equal on both alwayse. Fg is zero on both always

30. What can you say about the acceleration of gravity acting on the stone and the feather?a. It is greater on the featherb. It is greater on the stonec. It is zero on both due to vacuumd. It is equal on both alwayse. It is zero on both always

31. An astronaut on Earth kicks a bowling ball and hurts his foot. A year later, the same astronaut kicks a bowling ball on the Moon with the same force. His foot hurts…..

a. more b. less c. the same

32. A block of mass M rests on the floor of an elevator that is moving upward at constant speed. What is the relationship between the force due to gravity and the normal force on the block?

a. N > mg b. N = mg c. N < mg d. N = 0

e. depends on the size of the elevator

33. A block of mass M rests on the floor of an elevator that is accelerating upward. What is the relationship between the force due to gravity and the normal force on the block?

a. N > mg b. N = mg c. N < mg d. N = 0

e. depends on the size of the elevator

34. Below you see two cases: a physics student pulling or pushing a sled with a force F which is applied at an angle θ. In which case is the normal force greater?

a. case 1 b. case 2 c. it’s the same for both

d. depends on the magnitude of the force F e. depends on the ice surface

35. Consider two identical blocks, one resting on a flat surface, and the other resting on an incline. For which case is the normal force greater?

a. Case A b. case b c. both the same (N = mg)

d. both the same ( 0 < N < mg ) e. both the same ( N = 0 )

36. When you climb up a rope, the first thing you do is pull down on the rope. How do you manage to go up the rope by doing that?

a. This slows your initial velocity which is already upwardb. You don’t go up. You are too heavyc. You’re not really pulling down, it just seems that way.d. The rope actually pulls you up.e. You are pulling the ceiling down.

37. In outer space, a bowling ball and a ping-pong ball attract each other due to gravitational forces. How do the magnitudes of these attractive forces compare?

a. The bowling ball exerts a greater force on the ping pong ball.b. The ping pong ball exerts a greater force on the bowling ballc. The forces are equald. The forces are zero because they cancel oute. There are actually no forces at all

38. In outer space, gravitational forces exerted by a bowling ball and a ping pong ball on each other are equal and opposite. How do their accelerations compare?

a. They do not accelerate because they are weightlessb. Accelerations are equal but not oppositec. Accelerations are opposite but bigger for the bowling balld. Accelerations are opposite but bigger for the ping pong balle. Accelerations are equal and opposite

39. A small car collides with a large truck. Which experiences the greater impact force? a. The car b. the truck c. both the same

d. it depends on the velocity of each e. it depends on the mass of each

40. In the collision between the car and the truck, which has the greater acceleration?a. The car b. the truck c. both are the same

d. it depends on the velocity of each e. it depends on the mass of each

41. If you push with force F on either the heavy box (m1) or the light box (m2) , in which of the two cases below is the contact force between the two boxes larger?

a. Case A b. case B c. same in both cases

42. Two blocks of masses 2m and m are in contact on a horizontal frictionless surface. If a force F is applied to mass 2m, what is the force on mass m?

a. 2F b. F c. ½ F d. 1/3 F e. ¼ F

43. You tie a rope to a tree and you pull on the rope with a force of 100 N. What is the tension in the rope?

a. 0 N b. 50 N c. 100 N d. 150 N e. 200 N

44. Two tug of war opponents each pull with a force of 100 N on opposite ends of a rope. What is the tension in the rope?

a. 0 N b. 50 N c. 100 N d. 150 N e. 200 N

M2M1 M1M2

2MM

45. You and a friend can each pull with a force of 20 N. If you want to rip a rope in half, what is the best way?

a. You and your friend each pull on opposite ends of the ropeb. Tie the rope to a tree, and you both pull from the same end.c. It doesn’t matter both of the above are equivalentd. Get a large dog to bite the rope

46. Three blocks of mass 3m, 2m, and m are connected by strings and pulled with constant acceleration a. What is the relationship between the tensions in each of the strings?

a. T1 > T2 > T3 b. T1 < T2 < T3 c. T1 = T2 = T3

d. all tensions are zero e. tensions are random

47. In which case does block m experience a larger acceleration? In (1) there is a 10 kg mass hanging from a rope and falling. In (2) a hand is providing a constant downward force of 98 N. assume massless ropes.

a. Case 1 b. acceleration is zero c. both cases are the same

d. depends on the value of m e. case 2

3M2M M

T3 T2 T1

48. A box sits in a pickup truck on a frictionless truck bed. When the truck accelerates forward, the box slides off the back of the truck because

a. the force from the rushing air pushed it offb. the force of friction pushed it offc. no net force acted on the boxd. the truck went into reverse by accidente. none of the above

49. Antilock brakes keep the car wheels from locking and skidding during a sudden stop. Why does this help slow the car down?

a. µk > µs so sliding friction is betterb. µk > µs so static friction is betterc. µs < µk so sliding friction is betterd. µs < µk so static friction is bettere. None of the above

50. Your little sister wants you to give her a ride on her sled. On level ground, what is the easiest way to accomplish this?

a. Pushing her from behindb. Pulling her from the frontc. Both are equivalentd. It is impossible to move the slede. Tell her to get out and walk

51. A box of weight 100 N is at rest on a floor where µs = 0.5. A rope is attached to the box and pulled horizontally with tension T = 30 N. Which way does the box move?

a. Moves to the leftb. Moves to the rightc. Moves upd. Moves downe. The box does not move

52. A box sits on a flat board. You lift one end of the board, making an angle with the floor. As you increase the angle, the box will eventually begin to slide down. Why?

a. Component of the gravity force parallel to the plane increasedb. Coefficient of static friction decreasedc. Normal force exerted by the board decreased.d. Both a and ce. All of a, b, and c

53. A mass m is placed on an inclined plane and slides down the plane with constant speed. If a similar block of mass 2m were placed on the same incline it would (µ’s are the same)

a. Not move at allb. Slide a bit, slow down, then stopc. Accelerate down the inclined. Slide down at constant speede. Slide up at constant speed

54. A block of mass m sits on the ground. A student pulls up on the block with tension T, but the block remains in contact with the ground. What is the normal force on the block?

a. T + mg b. T - mg c. mg d. mg - T e. T

55. A mass hangs from two ropes at unequal angles, as shown. Which of the following makes correct comparisons of the horizontal and vertical components of the tension in each rope?

a. The horizontal and vertical tensions are greater in rope Bb. The horizontal tension is equal in both ropes but the vertical tension is greater in rope Ac. The horizontal tension is greater in rope A and the vertical tension is greater in rope Ad. The horizontal and vertical tensions are equal in both ropes e. The horizontal tension is greater in rope B and the vertical tensions are equal in both

AB

56. A free body diagram includes vectors representing the individual forces acting on an object. Which of these quantities should NOT appear on a free body diagram?

a. Tension of a ropeb. Mass times accelerationc. Kinetic frictiond. Static frictione. Weight

57. An object rolls along level ground to the right at constant speed. Must there be any forces pushing this object to the right?

a. Yes; the only forces that act must be to the rightb. Yes; but there could also be a friction force acting to the leftc. No; no forces can act to the rightd. No; while there can be forces acting, no force MUST acte. The answer depends on the speed of the object

58. Which of the following arrangements of three masses (hanging off the horizontal rod) would result in a balanced mobile? Note M1 = M2 = M3

Mass 1 Mass 2 Mass 3

a. X = 0.5 m x = 0 m x = 1.5 mb. X = 1 m x = 0 m x = 2 mc. X = 2 m x = 1 m x = 0 md. X = 0 m x = 1 m x = 0 me. X = 0.5 m x = 0 m x = 2 m

Pivot Point at 0.33 mark

59. In the diagram below, a picture frame held by two ropes is at rest. Find the value of the tension in rope 1.

a. 50 N b. 70 N c. 100 N d. 140 N e. 200 N

60. A force F of strength 20 N acts on an object of mass 3 kg as it moves a distance of 4 m. If f is perpendicular to the 4 m displacement, the work it does is equal to

a. 0 J b. 60 J c. 80 J d. 600 J e. 2400 J

61. Under the influence of a force, an object of mass 4 kg accelerates from 3 m/s to 6 m/s in 8 seconds. How much work was done on the object during this time?

a. 27 J b. 54 J c. 72 J d. 96 J e. cannot be determined

62. A box of mass m slides down a frictionless inclined plane of length L and vertical height h. What is the change in its gravitational potential energy?

a. –mgL b. –mgh c. –mgL/h d. –mgh/L e. –mghL

63. While a person lifts a book of mass 2 kg from the floor to a tabletop 1.5 m above the floor, how much work does the gravitational force do on the book?

a. -30 J b. -15 J c. 0 J d. 15 J e. 30 J

200 N

1 2

45˚ 45˚

64. A block of mass 3 kg slides down a frictionless inclined plane of length 6 m and height 4 m. If the block is released from rest at the top of the incline, what is its speed at the bottom?

a. 5 m/s b. 6 m/s c. 8 m/s d. 9 m/s e. 10 m/s

65. A block of mass 3 kg slides down an inclined plane of length 6 m and height 4 m. If the force of friction on the block is a constant 16 N as it slides from rest at the top of the incline, what is its speed at the bottom?

a. 2 m/s b. 3 m/s c. 4 m/s d. 5 m/s e. 6 m/s

66. A block of mass m slides from rest down an inclined plane of length s and height h. If f is the magnitude of the force of kinetic friction acting on the block as it slides, then the kinetic energy of the block when it reaches the bottom of the incline will be equal to

a. mgh b. mgh – Fh c. mgs - Fh d. mgh - Fs e. mgs - Fs

67. A force F is exerted at an angle θ on a box of mass m as it is dragged across the floor at constant velocity. If the box travels a distance x, then the work done by the force F on the box is

a. Fx b. Fxcos θ c. mgxcos θ d. Fxsin θ e. Fxtan θ