AP Physics Impulse and Momentum

Suppose that you're driving down the highway and a moth crashes into the windshield of your car. Which undergoes the greater acceleration? a. the moth b. your car c. both the same

A

In a physics experiment, two equal-mass carts roll towards each other on a level, low-friction track. One cart rolls rightward at 2 m/s and the other cart rolls leftward at 1 m/s. After the carts collide, they couple (attach together) and roll together with a speed of _____________. Ignore resistive forces. a. 0.5 m/s b. 0.33 m/s c. 0.67 m/s d. 1.0 m/s e. none of these

A (2 kg•m/s) - (1 kg•m/s) = (2 kg) v 1 kg•m/s = (2 kg)v (1 kg•m/s) / (2 kg) = v 0.5 m/s = v

13. A bat strikes a 0.050-kg baseball so that its velocity changes by +32 m/s in 0.080 s. With what average force was the ball struck? A) +20 N B) -20 N C) +200 N D) -200 N E) +10 N

A) +20 N

64. What is the speed of the "bullet + block" system immediately after the bullet is embedded in the block? A) 0.1 m/s B) 10 m/s C) 1000 m/s D) 10 000 m/s E) zero m/s

A) 0.1 m/s

54. A juggler demonstrates his abilities by keeping a 2.3-kg pipe wrench, a 1.5-kg hatchet, and a 1.0-kg hammer flying through the air above his head. The white circles on the graph represent the positions of the center of mass of each of the flying objects at one instant. What are the x and y coordinates of the center of mass for the system of these three objects? x y A) 0.46 m 0.47 m B) 0.30 m 0.54 m C) 0.42 m 0.60 m D) 0.47 m 0.26 m E) 0.60 m 0.42 m

A) 0.46 m 0.47 m

12. While a car is stopped at a traffic light in a storm, raindrops strike the roof of the car. The area of the roof is 5.0 m2. Each raindrop has a mass of 3.7 × 10-4 kg and speed of 2.5 m/s before impact and is at rest after the impact. If, on average at a given time, 150 raindrops strike each square meter, what is the impulse of the rain striking the car? A) 0.69 N s B) 0.046 N s C) 0.14 N s D) 11 N s E) 21 N s

A) 0.69 N s

25. While in Earth's orbit, an 80-kg astronaut carrying a 20-kg tool kit is initially drifting toward a stationary (relative to her) space shuttle at a speed of 2 m/s. If she throws the tool kit toward the shuttle with a speed of 6 m/s as seen from the shuttle, her final speed is A) 1 m/s toward the shuttle. B) 1 m/s away from the shuttle. C) 2 m/s toward the shuttle. D) 4 m/s toward the shuttle. E) 6 m/s away from the shuttle.

A) 1 m/s toward the shuttle.

39. A 50.0-kg boy runs at a speed of 10.0 m/s and jumps onto a cart as shown in the figure. The cart is initially at rest. If the speed of the cart with the boy on it is 2.50 m/s, what is the mass of the cart? A) 150 kg B) 175 kg C) 210 kg D) 260 kg E) 300 kg

A) 150 kg

59. A rocket is launched vertically from rest; and it burns fuel at a constant rate of 136 kg/s. Exhaust gases are expelled with a speed of 5.25 × 103 m/s relative to the rocket. What is the magnitude of the thrust? A) 7.14 × 105 N B) 3.64 × 106 N C) 2.59 × 10-2 N D) 808 N E) 38.6 N

A) 7.14 × 105 N

61. A 160-kg space probe is moving in the positive x direction at 18 km/s when it encounters a time-dependent force directed in the negative x direction. The force is as follows: Determine the final speed of the space probe. A) 8.6 km/s B) 5.3 km/s C) 11 km/s D) 16 km/s E) 23 km/s

A) 8.6 km/s

49. Two asteroids are drifting in space with trajectories shown. Assuming the collision at point O between them is completely inelastic, at what angle from its original direction is the larger asteroid deflected? A) 80° above the +x axis B) 69° above the +x axis C) 42° above the +x axis D) 47° above the +x axis E) 90° above the +x axis

A) 80° above the +x axis

34. A tennis ball has a velocity of 12 m/s downward just before it strikes the ground and bounces up with a velocity of 12 m/s upward. Which statement is true concerning this situation? A) The momentum of the ball and the momentum of the earth both change. B) Neither the momentum of the ball nor the momentum of the earth changes. C) The momentum of the ball is changed; and the momentum of the earth is not changed. D) The momentum of the ball is unchanged; and the momentum of the earth is changed. E) Both the momentum and the kinetic energy of the ball change because of the collision.

A) The momentum of the ball and the momentum of the earth both change.

A space vehicle of mass m has a speed v. At some instant, it separates into two pieces, each of mass 0.5m. One of the pieces is at rest just after the separation. 55. Which one of the following statements concerning this situation is true? A) The moving piece has speed 2v. B) This process conserves kinetic energy. C) The piece at rest possesses kinetic energy. D) The process does not conserve total energy. E) This process does not conserve momentum

A) The moving piece has speed 2v.

2. A rock is dropped from a high tower and falls freely under the influence of gravity. Which one of the following statements concerning the rock as it falls is true? Neglect the effects of air resistance. A) The rock will gain an equal amount of momentum during each second. B) The rock will gain an equal amount of kinetic energy during each second. C) The rock will gain an equal amount of speed for each meter through which it falls. D) The rock will gain an equal amount of momentum for each meter through which it falls. E) The amount of momentum the rock gains will be proportional to the amount of potential energy that it loses.

A) The rock will gain an equal amount of momentum during each second.

27. Complete the following statement: Different types of collisions between interacting bodies are categorized on the basis of A) kinetic energy conservation. B) mechanical energy conservation. C) linear momentum conservation. D) the magnitude of the forces involved. E) the temporal duration of the collision.

A) kinetic energy conservation.

33. A 2-kg stone falls 100 meters near the surface of the earth. It strikes the ground without any rebound thereby making a completely inelastic collision with the earth. Approximately how much kinetic energy is transferred to the earth in this process? A) zero joules B) 200 J C) 2000 J D) 10 000 J E) 20 000 J

A) zero joules

66. What is the speed of the center of mass of this system after the explosion? A) zero m/s B) 1 m/s C) 3 m/s D) 5 m/s E) 7 m/s

A) zero m/s

Which of the following objects have momentum? Include all that apply. a. An electron is orbiting the nucleus of an atom. b. A UPS truck is stopped in front of the school building. c. A Yugo (a compact car) is moving with a constant speed. d. A small flea walking with constant speed across Fido's back. e. The high school building rests in the middle of town.

A, C and D

A wad of chewed bubble gum is moving with 1 unit of momentum when it collides with a heavy box that is initially at rest. The gum sticks to the box and both are set in motion with a combined momentum that is ___. a. less than 1 unit b. 1 unit c. more than 1 unit d. not enough information

B

17. What, approximately, is the speed of the block at t = 11 seconds? A) 5.0 m/s B) 16 m/s C) 25 m/s D) 65 m/s E) 75 m/s

B) 16 m/s

48. A 0.50-kg bomb is sliding along an icy pond (frictionless surface) with a velocity of 2.0 m/s to the west. The bomb explodes into two pieces. After the explosion, a 0.20-kg piece moves south at 4.0 m/s. What are the components of the velocity of the 0.30-kg piece? A) 4.0 m/s north, 0 m/s B) 2.7 m/s north, 3.3 m/s west C) 4.0 m/s north, 2.7 m/s west D) 0 m/s, 2.0 m/s east E) 4.0 m/s north, 2.0 m/s east

B) 2.7 m/s north, 3.3 m/s west

37. A 0.050-kg lump of clay moving horizontally at 12 m/s strikes and sticks to a stationary 0.15-kg cart that can move on a frictionless air track. Determine the speed of the cart and clay after the collision. A) zero m/s B) 3 m/s C) 6 m/s D) 9 m/s E) 12 m/s

B) 3 m/s

A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown. Two seconds after it begins sliding, a horizontal, time-dependent force is applied to the mass. The force is removed eight seconds later. The graph shows how the force on the block varies with time. 16. What is the magnitude of the total impulse of the force acting on the block? A) 20 N s B) 42 N s C) 48 N s D) 54 N s E) 60 N s

B) 42 N s

52. The drawing shows two 4.5-kg balls located on the y axis at 1.0 and 9.0 m, respectively, and a third ball with a mass 2.3 kg which is located at 6.0 m. What is the location of the center of mass of this system? A) 4.8 m B) 5.2 m C) 5.6 m D) 6.0 m E) 6.4 m

B) 5.2 m

A 2.0-kg pistol fires a 1.0-g bullet with a muzzle speed of 1000 m/s. The bullet then strikes a 10-kg wooden block resting on a horizontal frictionless surface. The block and the embedded bullet then slide across the surface. 62. What is the kinetic energy of the bullet as it travels toward the block? A) 100 J B) 500 J C) 1000 J D) 5000 J E) 10 000 J

B) 500 J

32. Two objects of equal mass collide on a horizontal frictionless surface. Before the collision, object A is at rest while object B has a constant velocity of 12 m/s. After the collision, the two objects are stuck together. What is the speed of the composite body (A + B) after the collision? A) 3.0 m/s B) 6.0 m/s C) 12 m/s D) 24 m/s E) 36 m/s

B) 6.0 m/s

58. A mother is holding her 4.5-kg baby in her arms while riding in a car moving at 22 m/s. The car is involved in a head-on collision and stops within 1.5 seconds. What is the magnitude of the force exerted by the baby on his mother's arms? A) 45 N B) 66 N C) 90 N D) 99 N E) 150 N

B) 66 N

21. A 100-kg cannon at rest contains a 10-kg cannon ball. When fired, the cannon ball leaves the cannon with a speed of 90 m/s. What is the recoil speed of the cannon? A) 4.5 m/s B) 9 m/s C) 45 m/s D) 90 m/s E) zero m/s

B) 9 m/s

9. A 0.065-kg tennis ball moving to the right with a speed of 15 m/s is struck by a tennis racket, causing it to move to the left with a speed of 15 m/s. If the ball remains in contact with the racquet for 0.020 s, what is the magnitude of the average force exerted on the ball? A) zero newtons B) 98 N C) 160 N D) 240 N E) 320 N

B) 98 N

23. A sled of mass m is coasting on the icy surface of a frozen river. While it is passing under a bridge, a package of equal mass m is dropped straight down and lands on the sled (without causing any damage). The sled plus the added load then continue along the original line of motion. How does the kinetic energy of the (sled + load) compare with the original kinetic energy of the sled? A) It is 1/4 the original kinetic energy of the sled. B) It is 1/2 the original kinetic energy of the sled. C) It is 3/4 the original kinetic energy of the sled. D) It is the same as the original kinetic energy of the sled. E) It is twice the original kinetic energy of the sled.

B) It is 1/2 the original kinetic energy of the sled.

43. Two objects constitute an isolated system. In an elastic collision between the two objects, which one of the following statements is a false statement? A) The total kinetic energy is conserved. B) The kinetic energy of each object is the same before and after the collision. C) The total momentum is conserved. D) The magnitude of the force exerted by each object on the other object is equal. E) The total kinetic energy before the collision is equal to the total kinetic energy after the collision.

B) The kinetic energy of each object is the same before and after the collision.

10. A baseball of mass m, initially at rest, is struck by a bat so that it acquires a speed v. If t represents the duration of the collision between the bat and the ball, which one of the following expressions determines the magnitude of the average force exerted on the ball? A) (1/2)mv2 B) mv/t C) (1/2)mv2t D) mt2/(2v) E) mvt

B) mv/t

A relatively large force acting for a relatively long amount of time on a relatively small mass will produce a relatively ______. List all that apply. a. small velocity change b. large velocity change c. small momentum change d. small acceleration

B: A large force acting upon a small mass will result in a large acceleration (a=F/m) and subsequently a large velocity change (Delta v = a*t). This rules out choices A and D. A large force and for a long time will result in a large impulse and therefore a large momentum change. This rules out choice C.

Which of the following statements are true about impulse? a) Impulse is a force. b) Impulse is a vector quantity. c) An object which is traveling east would experience a westward directed impulse in a collision. d) Objects involved in collisions encounter impulses. e) The Newton is the unit for impulse. f) The kg•m/s is equivalent to the units on impulse. g) An object which experiences a net impulse will definitely experience a momentum change. h) In a collision, the net impulse experienced by an object is equal to its momentum change. i) A force of 100 N acting for 0.1 seconds would provide an equivalent impulse as a force of 5 N acting for 2.0 seconds.

BDFGHI

Which of the following are true about the relationship between momentum end energy? a) Momentum is a form of energy. b) If an object has momentum, then it must also have mechanical energy. c) If an object does not have momentum, then it definitely does not have mechanical energy either. d) Object A has more momentum than object B. Therefore, object A will also have more kinetic energy. e) Two objects of varying mass have the same momentum. f) The least massive of the two objects will have the greatest kinetic energy.

BE

A physics cart rolls along a low-friction track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is ____. a. zero b. four times as large c. twice as large d. unchanged

C

A truck driving along a highway road has a large quantity of momentum. If it moves at the same speed but has twice as much mass, its momentum is ________________. a. zero b. quadrupled c. doubled d. unchanged

C

Consider the concepts of work and energy (presuming you have already studied it) and those of impuse and momentum. Force and time is related to momentum change in the same manner as force and displacement pertains to ___________. a. impulse b. work c. energy change d. velocity e. none of these.

C

In order to catch a ball, a baseball player naturally moves his or her hand backward in the direction of the ball's motion once the ball contacts the hand. This habit causes the force of impact on the players hand to be reduced in size principally because ___. A)the resulting impact velocity is lessened B)the momentum change is decreased C)the time of impact is increased D)the time of impact is decreased E) none of these

C

Suppose that you're driving down the highway and a moth crashes into the windshield of your car. Which undergoes the greater change is momentum? a. the moth b. your car c. both the same

C

Suppose that you're driving down the highway and a moth crashes into the windshield of your car. Which undergoes the greater force? a. the moth b. your car c. both the same

C

Suppose that you're driving down the highway and a moth crashes into the windshield of your car. Which undergoes the greater impulse? a. the moth b. your car c. both the same

C

The firing of a bullet by a rifle causes the rifle to recoil backwards. The speed of the rifle's recoil is smaller than the bullet's forward speed because the ___. a. force against the rifle is relatively small b. speed is mainly concentrated in the bullet c. rifle has lots of mass d. momentum of the rifle is unchanged e. none of these

C

Two objects, A and B, have the same size and shape. Object A is twice as massive as B. The objects are simultaneously dropped from a high window on a tall building. (Neglect the effect air resistance.) The objects will reach the ground at the same time but object A will have a greater ___. Choose all that apply. a. speed b. acceleration c. momentum d. none of the above quantities will be greater

C

If a force is exerted on an object, which statement is true? a) a large force always produces a large change in the object's momentum b) a large force produces a large change in the object's momentum only if the force is applied over a very short time interval c) A small force applied over a long time interval can produce a large change in the object's momentum d) a small force always produces a large change in the object's momentum

C A small force applied over a long time interval can produce a large change in the object's momentum

When comparing the momentum of two moving objects, which of the following is correct? a) The object with the higher velocity will have less momentum if the masses are equal. b) The more massive object will have less momentum if its velocity is greater. c) The less massive object will have less momentum if the velocities are the same. d) The more massive object will have less momentum if the velocities are the same.

C The less massive object will have less momentum if the velocities are the same.

24. A bullet of mass m is fired at speed v0 into a wooden block of mass M. The bullet instantaneously comes to rest in the block. The block with the embedded bullet slides along a horizontal surface with a coefficient of kinetic friction . Which one of the following expressions determines how far the block slides before it comes to rest (the magnitude of displacement s in the figure)? A) B) C) D) E)

C)

22. A 50-kg toboggan is coasting on level snow. As it passes beneath a bridge, a 20-kg parcel is dropped straight down and lands in the toboggan. If KE1 is the original kinetic energy of the toboggan and KE2 is the kinetic energy after the parcel has been added, what is the ratio KE2/KE1. A) 0.4 B) 0.6 C) 0.7 D) 0.8 E) 1

C) 0.7

35. A 3.0-kg cart moving to the right with a speed of 1.0 m/s has a head-on collision with a 5.0-kg cart that is initially moving to the left with a speed of 2.0 m/s. After the collision, the 3.0-kg cart is moving to the left with a speed of 1.0 m/s. What is the final velocity of the 5.0-kg cart? A) zero m/s B) 0.80 m/s to the right C) 0.80 m/s to the left D) 2.0 m/s to the right E) 2.0 m/s to the left

C) 0.80 m/s to the left

57. How much work was done by the internal forces that caused the separation? A) zero joules B) C) D) mv2 E) 2mv2

C) 1/2 mv2

8. A machine gun fires 25-g bullets at the rate of 4 bullets per second. The bullets leave the gun at a speed of 1000 m/s. What is the average recoil force experienced by the machine gun? A) 10 N B) 20 N C) 100 N D) 200 N E) 1000 N

C) 100 N

50. In the game of billiards, all the balls have approximately the same mass, about 0.17 kg. In the figure, the cue ball strikes another ball such that it follows the path shown. The other ball has a speed of 1.5 m/s immediately after the collision. What is the speed of the cue ball after the collision? A) 1.5 m/s B) 1.8 m/s C) 2.6 m/s D) 4.3 m/s E) 5.2 m/s

C) 2.6 m/s

6. A projectile is launched with a momentum of 200 kg • m/s and 1000 J of kinetic energy. What is the mass of the projectile? A) 5 kg B) 10 kg C) 20 kg D) 40 kg E) 50 kg

C) 20 kg

26. While on an interplanetary mission, a 58.5-kg astronaut is floating toward the front of her ship at 0.15 m/s, relative to the ship. She wishes to stop moving, relative to the ship. She decides to throw away the 2.50-kg book she's carrying. What should the approximate speed and direction of the book be to achieve her goal? A) 0.15 m/s, toward the front of the ship B) 3.5 m/s, toward the back of the ship C) 3.7 m/s, toward the front of the ship D) 0.30 m/s, toward the back of the ship E) 1.5 m/s, toward the front of the ship

C) 3.7 m/s, toward the front of the ship

7. A 0.2-kg steel ball is dropped straight down onto a hard, horizontal floor and bounces straight up. The ball's speed just before and just after impact with the floor is 10 m/s. Determine the magnitude of the impulse delivered to the floor by the steel ball. A) zero N s B) 2 N s C) 4 N s D) 20 N s E) 200 N s

C) 4 N s

A stationary 4-kg shell explodes into three pieces. Two of the fragments have a mass of 1 kg each and move along the paths shown with a speed of 10 m/s. The third fragment moves upward as shown. 65. What is the speed of the third fragment? A) zero m/s B) 1 m/s C) 5 m/s D) 10 m/s E) 20 m/s

C) 5 m/s

4. Jennifer is walking at 1.22 m/s. If Jennifer weighs 552 N, what is the magnitude of her momentum? A) 97.0 kg m/s B) 137 kg m/s C) 68.6 kg m/s D) 672 kg m/s E) 951 kg m/s

C) 68.6 kg m/s

11. An airplane is traveling at 225 m/s when it strikes a weather balloon (m = 1.82 kg), which can be considered to be at rest relative to the ground below. After the collision, the balloon is caught on the fuselage and is traveling with the airplane. The collision takes place over a time interval of 4.44 × 10-3 N. What is the average force that the balloon exerts on the airplane during the collision? A) 415 N B) 2.78 × 104 N C) 9.22 × 104 N D) 4.61 × 105 N E) 5.07 × 106 N

C) 9.22 × 104 N

20. An object of mass 3m, initially at rest, explodes breaking into two fragments of mass m and 2m, respectively. Which one of the following statements concerning the fragments after the explosion is true? A) They will fly off at right angles. B) They will fly off in the same direction. C) The smaller fragment will have twice the speed of the larger fragment. D) The larger fragment will have twice the speed of the smaller fragment. E) The smaller fragment will have four times the speed of the larger fragment

C) The smaller fragment will have twice the speed of the larger fragment.

A 5-N force is applied to a 3-kg ball to change its velocity from +9 m/s to +3 m/s. The impulse experienced by the ball is ____ N•s. a. -2.5 b. -10 c. -18 d. -45 e. none of these

C: Impulse is defined as a force acting upon and object for a given amount of time. Impulse can be computed by multiplying force*time. But in this problem, the time is not known. Never fear - the impulse equals the momentum change. The momentum change in this problem is -18 kg•m/s Thus, the impulse is -18 N•s.

A 5-N force is applied to a 3-kg ball to change its velocity from +9 m/s to +3 m/s. This impulse causes the momentum change of the ball to be ____ kg•m/s. a. -2.5 b. -10 c. -18 d. -45 e. none of these

C: the momentum change of an object can be found if the mass and the velocity change are known. In this equation, m=3 kg and the velocity change is -6 m/s. When finding the velocity change, always subtract the initial velocity from the final velocity (vf - vi).

It is NOT possible for a rocket to accelerate in outer space because ____. List all that apply. A)there is no air in space B)there is no friction in space C)there is no gravity in outer space D)... nonsense! Rockets do accelerate in outer space.

D

Suppose that Paul D. Trigger fires a bullet from a gun. The speed of the bullet leaving the muzzle will be the same as the speed of the recoiling gun ____. A) because momentum is conserved B) because velocity is conserved C) because both velocity and momentum are conserved D)only if the mass of the bullet equals the mass of the gun E)none of these

D

Consider a karate expert. During a talent show, she executes a swift blow to a cement block and breaks it with her bare hand. During the collision between her hand and the block, the ___. a)time of impact on both the block and the expert's hand is the same b)force on both the block and the expert's hand have the same magnitude c) impulse on both the block and the expert's hand have the same magnitude d) all of the above. e) none of the above.

D - All of the above

41. A 7.30-kg bowling ball strikes a 1.60-kg pin at rest head-on. Before the collision, the velocity of the ball is +6.00 m/s. After the collision, the velocity of the ball is +5.40 m/s. What is the velocity of the pin after the collision? A) +0.6 m/s B) +5.4 m/s C) +1.2 m/s D) +2.7 m/s E) +3.2 m/s

D) +2.7 m/s

38. A 0.10-kg cart traveling in the positive x direction at 10.0 m/s collides with a 0.30-kg cart at rest. The collision is elastic. What is the velocity of the 0.10-kg cart after the collision? A) +2.5 m/s B) -2.5 m/s C) +5 m/s D) -5 m/s E) +3.3 m/s

D) -5 m/s

40. A 0.015-kg marble moving to the right at 0.40 m/s has a head-on, elastic collision with a 0.045-kg marble sitting at rest on a smooth, level surface. Which of the following are the correct magnitudes and directions of the velocities of the two marbles after the collision? 0.015 kg marble 0.045 kg marble A) 0.15 m/s, left 0.25 m/s, right B) 0.10 m/s, right 0.30 m/s, right C) zero m/s 0.25 m/s, right D) 0.20 m/s, left 0.20 m/s, right E) 0.40 m/s, left zero m/s

D) 0.20 m/s, left 0.20 m/s, right

53. During hockey practice, two pucks are sliding across the ice in the same direction. At one instant, a 0.18-kg puck is moving at 16 m/s while the other puck has a mass of 0.14 kg and a speed of 3.8 m/s. What is the velocity of the center of mass of the two pucks? A) 5.0 m/s B) 7.0 m/s C) 9.0 m/s D) 11 m/s E) 13 m/s

D) 11 m/s

15. A football player kicks a 0.41-kg football initially at rest; and the ball flies through the air. If the kicker's foot was in contact with the ball for 0.051 s and the ball's initial speed after the collision is 21 m/s, what was the magnitude of the average force on the football? A) 9.7 N B) 46 N C) 81 N D) 170 N E) 210 N

D) 170 N

14. The head of a hammer (m = 1.5 kg) moving at 4.5 m/s strikes a nail and bounces back with the same speed after an elastic collision lasting 0.075 s. What is the magnitude of the average force the hammer exerts on the nail? A) 6.8 N B) 60 N C) 90 N D) 180 N E) 240 N

D) 180 N

36. A 1000-kg car traveling east at 20 m/s collides with a 1500-kg car traveling west at 10 m/s. The cars stick together after the collision. What is the common velocity of the cars after the collision? A) 16 m/s, east B) 6 m/s, west C) 4 m/s, east D) 2 m/s, east E) 1 m/s, west

D) 2 m/s, east

47. Car One is traveling due north and Car Two is traveling due east. After the collision shown, Car One rebounds in the due south direction. Which of the numbered arrows is the only one that can represent the final direction of Car Two? A) 1 B) 2 C) 3 D) 4 E) 5

D) 4

46. How much kinetic energy was released in the collision? A) 8.28 × 1022 J B) 3.51 × 1027 J C) 7.02 × 1027 J D) 4.14 × 1022 J E) 1.50 × 1013 J

D) 4.14 × 1022 J

29. Which one of the following is characteristic of an inelastic collision? A) Total mass is not conserved. B) Total energy is not conserved. C) Linear momentum is not conserved. D) Kinetic energy is not conserved. E) The change in momentum is less than the total impulse.

D) Kinetic energy is not conserved.

19. A stationary bomb explodes in space breaking into a number of small fragments. At the location of the explosion, the net force due to gravity is zero newtons. Which one of the following statements concerning this event is true? A) Kinetic energy is conserved in this process. B) All of the fragments must have equal kinetic energies. C) The sum of the kinetic energies of the fragments must be zero. D) The vector sum of the linear momenta of the fragments must be zero. E) The mass of any one fragment must be equal to the mass of any other fragment

D) The vector sum of the linear momenta of the fragments must be zero.

56. What is the kinetic energy of the moving piece just after the separation? A) zero joules B) C) D) mv2 E) 2mv2

D) mv2

31. Complete the following statement: Momentum will be conserved in a two-body collision only if A) both bodies come to rest. B) the collision is perfectly elastic. C) the kinetic energy of the system is conserved. D) the net external force acting on the two-body system is zero. E) the internal forces of the two body system cancel in action-reaction pairs.

D) the net external force acting on the two-body system is zero.

Three boxes, X, Y, and Z, are at rest on a table as shown in the diagram at the right. The weight of each box is indicated in the diagram. The net or unbalanced force acting on box Y is _____. a. 4 N down b. 5 N down c. 5 N up d. 10 N up e. zero

E

44. A 35-kg girl is standing near and to the left of a 43-kg boy on the frictionless surface of a frozen pond. The boy throws a 0.75-kg ice ball to the girl with a horizontal speed of 6.2 m/s. What are the velocities of the boy and the girl immediately after the girl catches the ice ball? girl boy A) 0.81 m/s, left 0.67 m/s, right B) 0.17 m/s, left 0.14 m/s, left C) 0.18 m/s, right 0.13 m/s, left D) 0.42 m/s, left 0.49 m/s, right E) 0.13 m/s, left 0.11 m/s, right

E) 0.13 m/s, left 0.11 m/s, right

A comet fragment of mass 1.96 × 1013 kg is moving at 6.50 × 104 m/s when it crashes into Callisto, a moon of Jupiter. The mass of Callisto is 1.08 × 1023 kg. The collision is completely inelastic. 45. Assuming for this calculation that Callisto's initial momentum is zero kg m/s, what is the recoil speed of Callisto immediately after the collision? A) 3.34 × 10-18 m/s B) 1.27 × 10-14 m/s C) 3.58 × 10-12 m/s D) 6.13 × 10-7 m/s E) 1.18 × 10-5 m/s

E) 1.18 × 10-5 m/s

63. The explosive charge in the pistol acts for 0.001 s. What is the average force exerted on the bullet while it is being fired? A) 0.001 N B) 1.0 N C) 100 N D) 500 N E) 1000 N

E) 1000 N

5. A 1.0-kg ball has a velocity of 12 m/s downward just before it strikes the ground and bounces up with a velocity of 12 m/s upward. What is the change in momentum of the ball? A) zero kg m/s B) 12 kg m/s, downward C) 12 kg m/s, upward D) 24 kg m/s, downward E) 24 kg m/s, upward

E) 24 kg m/s, upward

42. A 2.5-kg ball and a 5.0-kg ball have an elastic collision. Before the collision, the 2.5-kg ball was at rest and the other ball had a speed of 3.5 m/s. What is the kinetic energy of the 2.5-kg ball after the collision? A) 1.7 J B) 3.4 J C) 8.1 J D) 14 J E) 27 J

E) 27 J

60. A 100-kg fisherman and a 500-kg supply crate are on a frozen pond that is essentially frictionless. The man and the crate are initially separated by a distance of 600 meters. The fisherman uses a very light rope to pull the crate closer to him. How far has the man moved when the crate reaches the fisherman? A) zero meters B) 10 m C) 50 m D) 100 m E) 500 m

E) 500 m

18. In which one of the following situations is linear momentum not conserved? A) A bomb suspended by a string explodes into one hundred fragments. B) A bowling ball collides with a set of ten pins. C) A golf ball is struck by a club. D) An astronaut floating in space throws a hammer away and subsequently moves in the opposite direction. E) A tree limb is struck by lightning and falls to the ground.

E) A tree limb is struck by lightning and falls to the ground

1. Which one of the following statements concerning momentum is true? A) Momentum is a force. B) Momentum is a scalar quantity. C) The SI unit of momentum is kg m2/s. D) The momentum of an object is always positive. E) Momentum and impulse are measured in the same units.

E) Momentum and impulse are measured in the same units.

3. A stunt person jumps from the roof of a tall building, but no injury occurs because the person lands on a large, air-filled bag. Which one of the following best describes why no injury occurs? A) The bag provides the necessary force to stop the person. B) The bag reduces the impulse to the person. C) The bag increases the amount of time the force acts on the person and reduces the change in momentum. D) The bag decreases the amount of time during which the momentum is changing and reduces the average force on the person. E) The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.

E) The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.

51. Which one of the following statements concerning center of mass is true? A) All of an object's mass is located at its center of mass. B) The center of mass of an object must be located within the object. C) The center of mass of a system of objects cannot change even if there are forces acting on the objects. D) The velocity of the center of mass of a system of objects is greatly affected by a collision of objects within the system. E) The velocity of the center of mass of a system of objects is constant when the sum of the external forces acting on the system is zero.

E) The velocity of the center of mass of a system of objects is constant when the sum of the external forces acting on the system is zero.

30. Two objects of equal mass traveling toward each other with equal speeds undergo a head on collision. Which one of the following statements concerning their velocities after the collision is necessarily true? A) They will exchange velocities. B) Their velocities will be reduced. C) Their velocities will be unchanged. D) Their velocities will be zero. E) Their velocities may be zero.

E) Their velocities may be zero.

28. Complete the following statement: A collision is elastic if A) the final velocities are zero. B) the objects stick together. C) the final kinetic energy is zero. D) the final momentum is zero. E) the total kinetic energy is conserved.

E) the total kinetic energy is conserved.

TRUE or FALSE: A ball is dropped from the same height upon various flat surfaces. For the same collision time, impulses are smaller when the most bouncing take place.

False

A roller coaster climbs up a hill at 4m/s and then zips down the hill at 30m/s. The momentum of the roller coaster

is greater up the hill than down the hill

What equation can be used to directly calculate an object's momentum, p?

p=mv

A rubber ball moving at the speed of 5m/s hits a flat wall and returned to the thrower at 5m/s. The magnitude of the momentum of the rubber ball

remained the same

A 4 kg object has a momentum of 12 kg•m/s. The object's speed is ___ m/s. a. 3 b. 4 c. 12 d. 48 e. none of these.

A: p=m*v with m=4 kg and p=12 kg•m/s.

Which of the following statements are true about collisions? a) Two colliding objects will exert equal forces upon each other even if their mass is significantly different. b) During a collision, an object always encounters an impulse and a change in momentum. c) During a collision, the impulse which an object experiences is equal to its velocity change. d) The velocity change of two respective objects involved in a collision will always be equal. e) While individual objects may change their velocity during a collision, the overall or total velocity of the colliding objects is conserved. f) In a collision, the two colliding objects could have different acceleration values. g) In a collision between two objects of identical mass, the acceleration values could be different. h)Total momentum is always conserved between any two objects involved in a collision. i)When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater collision force. j)When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater momentum change. k)A moving object collides with a stationary object; the stationary object has significantly less mass. The stationary object encounters the greater collision force. l)A moving object collides with a stationary object; the stationary object has significantly less mass. The stationary object encounters the greater momentum change.

ABF

Cars are equipped with padded dashboards. In collisions, the padded dashboards would be safer than non-padded ones because they ____. List all that apply. a. increase the impact time b. decrease an occupant's impulse c. decrease the impact force d. none of the above

AC

Which of the following statements are true about momentum? a) Momentum is a vector quantity. b) The standard unit on momentum is the Joule. c) An object with mass will have momentum. d) An object which is moving at a constant speed has momentum. e) An object can be traveling eastward and slowing down; its momentum is westward. f)Momentum is a conserved quantity; the momentum of an object is never changed. g) The momentum of an object varies directly with the speed of the object. h) Two objects of different mass are moving at the same speed; the more massive object will have the greatest momentum. i) A less massive object can never have more momentum than a more massive object. j) Two identical objects are moving in opposite directions at the same speed. The forward moving object will have the greatest momentum. k) An object with a changing speed will have a changing momentum.

ADGHK

Which of the following statements are true about elastic and inelastic collisions? Perfectly elastic and perfectly inelastic collisions are the two opposite extremes along a continuum; where a particular collision lies along the continuum is dependent upon the amount kinetic energy which is conserved by the two objects. Most collisions tend to be partially to completely elastic. Momentum is conserved in an elastic collision but not in an inelastic collision. The kinetic energy of an object remains constant during an elastic collision. Elastic collisions occur when the collision force is a non-contact force. Most collisions are not inelastic because the collision forces cause energy of motion to be transformed into sound, light and thermal energy (to name a few). A ball is dropped from rest and collides with the ground. The higher that the ball rises upon collision with the ground, the more elastic that the collision is. A moving air track glider collides with a second stationary glider of identical mass. The first glider loses all of its kinetic energy during the collision as the second glider is set in motion with the same original speed as the first glider. Since the first glider lost all of its kinetic energy, this is a perfectly inelastic collision. The collision between a tennis ball and a tennis racket tends to be more elastic in nature than a collision between a halfback and linebacker in football.

AEFGI