Choose the best answer to each question and write the appropriate letter in the space provided.

1) The momentum of an object is defined as the object's __.

A) mass times it acceleration
B) mass times its velocity
C) force times its acceleration
D) force times the time interval
E) velocity times the time interval

2) Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?
A) The large truck
B) The small truck
C) Both have the same momentum

3) Compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has __
A) the same momentum
B) twice as much momentum
C) four times as much momentum

4) If the momentum of an object changes and its mass remains constant, __
A) its velocity is changing
B) it is accelerating (or decelerating)
C) there is a force acting on it
D) all of the above
E) none of the above

5) The momentum change of an object is equal to the __
A) force acting on it
B) velocity change of the object
C) impulse acting on it
D) object's mass times the force acting on it
E) force acting on it times its velocity

6) In order to increase the final momentum of a golf ball, we could __
A) increase the force acting on it
B) increase the time of contact with the ball
C) follow through when hitting the ball
D) swing as hard as possible
E) all of the above

7) The reason padded dashboards are used in cars is that they __
A) look nice and feel good
B) increase the force of impact in a collision
C) increase the time of impact in a collision
D) decrease the momentum of a collision
E) decrease the impulse in a collision

8) A Ping-Pongä ball launcher is fired Compared to the force on the ball, the force on the launcher is __
A) larger
B) smaller
C) the same

9) A Ping-Pongä ball launcher is fired Compared to the impulse on the ball, the impulse on the launcher is __
A) larger
B) smaller
C) the same

10) Momentum of a system is conserved only when __
A) there are no forces acting on the system
B) there is no net external force acting on the system
C) there are no internal forces acting on the system
D) the system is not moving
E) the system has zero momentum

11) A collision is considered elastic if __
A) there is no sound generated during the collision
B) there is no lasting deformation
C) the objects that collide don't get hot
D) after the collision, the objects have the same shape as before the collision
E) all of the above _______

12) Suppose a girl is standing on a pond where there is no friction between her feet and the ice In order to get off the ice, she can __
A) bend over touching the ice in front of her, then bring her feet to her hands
B) throw something in the direction opposite to that in which she wants to go
C) walk very slowly on tiptoe
D) get on her hands and knees and crawl off the ice
E) all of the above will work _______

13) Which of the following has the largest momentum?
A) A tightrope walker crossing Niagara Falls
B) A pickup truck traveling down the highway
C) A Mack truck parked in a parking lot
D) The science building at your school
E) A dog running down the street _______

14) A freight train rolls along a track with considerable momentum If it were to roll at the same speed but had twice as much mass, its momentum would be __
A) zero
B) doubled
C) quadrupled
D) unchanged _______

15) A cannon recoils from launching a cannonball The speed of the cannon's recoil is small because the __
A) force against the cannon is relatively small
B) impulse on the cannon is less than the impulse on the cannonball
C) cannon has far more mass than the cannonball
D) momentum of the cannon is unchanged
E) none of the above _______

16) Suppose a cannon is made of a strong but very light material Suppose also that the cannonball is more massive than the cannon itself For such a system __
A) the target would be a safer place than where the operator is located
B) recoil problems would be lessened
C) conservation of energy would not hold
D) conservation of momentum would not hold
E) the force on the cannonball would be greater than the force on the cannon _______

17) Two objects, A and B, have the same size and shape, but A is twice as heavy as B When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has a higher __
A) speed
B) acceleration
C) momentum
D) all of the above
E) none of the above _______

18) In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion Doing this reduces the force of impact on the player's hand principally because __ A) the velocity of the hand is reduced
B) the momentum of impact is reduced
C) the time of impact is increased
D) the time of impact is decreased
E) none of the above _______

19) A car traveling along the highway needs a certain amount of force exerted on it to stop More stopping force may be required when the car has __
A) more mass
B) more momentum
C) less stopping distance
D) all of the above
E) none of the above _______

20) A cannon fires a cannonball The speed of the cannonball will be the same as the speed of the recoiling cannon __
A) because momentum is conserved
B) because velocity is conserved
C) because both velocity and momentum are conserved
D) if the mass of the cannonball equals the mass of the cannon
E) none of the above _______

21) The force of an apple hitting the ground depends upon __
A) air resistance on the apple as it falls
B) the speed of the apple just before it hits
C) the time of impact with the ground
D) whether or not the apple bounces
E) all of the above _______

22) When you jump off a step, you usually bend your knees as you reach the ground By doing this, the time of the impact is about 10 times more what it would be in a stiff-legged landing and the average force on your body is reduced by __
A) less than 10 times B) more than 10 times C) about 10 times _______

23) Recoil is noticeable if we throw a heavy ball while standing on roller skates If instead we go through the motions of throwing the ball but hold onto it, our net recoil velocity will be __
A) zero
B) the same as before
C) small but noticeable _______

24) A 1-N apple falls to the ground The apple hits the ground with an impact force of about __
A) 1 N
B) 2 N
C) 4 N
D) 9.8 N
E) Not enough information to say _______

25) A karate expert executes a swift blow and severs a cement block with her bare hand
A) The impulse on both the block and the expert's hand have the same magnitude
B) The force on both the block and the expert's hand have the same magnitude
C) The time of impact on both the block and the expert's hand is the same
D) all of the above
E) none of the above _______

26) A moving freight car runs into an identical car at rest on the track The cars couple together Compared to the velocity of the first car before the collision, the velocity of the combined cars after the collision is __
A) twice as large
B) the same
C) one half as large
D) zero
E) More information is needed to say _______

27) Two gliders having the same mass and speeds move toward each other on an air track and stick together After the collision the velocity of the gliders is __
A) twice the original velocity
B) the same as the original velocity
C) one half the original velocity
D) zero
E) There is not enough information to say _______

28) A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest After the putty sticks to the ball, both are set in motion with a combined momentum that is __
A) less than 1 unit
B) more than 1 unit
C) 1 unit
D) Not enough information to say _______

29) The force that accelerates a rocket into outer space is exerted on the rocket by the __
A) Earth's gravity
B) rocket's wings
C) atmospheric pressure
D) exhaust gases
E) none of the above _______

30) If all people, animals, trains and trucks all over the world began to walk or run towards the east, then __
A) the earth would spin a bit faster
B) the earth would spin a bit slower
C) the earth's spin would not be affected at all ______

31) Suppose an astronaut in outer space wishes to play a solitary "throw, bounce, and catch" game by tossing a ball against a very massive and perfectly elastic concrete wall If the ball is as massive as the astronaut, then __
A) the astronaut will catch one bounce only
B) the astronaut will never catch the first bounce
C) the astronaut's time between catches will decrease as the game progresses
D) none of the above _______

32) A golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move The bowling ball is set in motion with a momentum of __
A) less than 1 unit
B) more than 1 unit
C) 1 unit
D) not enough information _______

33) Superman is at rest in space when he throws an asteroid that has more mass than he does Which moves faster, Superman or the asteroid?

A) The asteroid B) Superman C) They both move at the same speed _______

34) A cannonball shot from a long-barrel cannon travels faster than one shot from a short-barrel cannon because the cannonball receives a greater __

A) force B) impulse C) both A and B D) neither A nor B _______

35) While rollerblading, Granny collides with her tiny grandson Ambrose who is at rest Ignoring any friction effects, Ambrose's speed after the collision will be greatest when __

A) he and Granny make a bouncing collision, each going separate ways
B) Granny catches him and they both move together _______

36) A small economy car (low mass) and a limousine (high mass) are pushed from rest across a parking lot, equal distances with equal forces The car that receives the greater impulse is the __
A) small economy car
B) limousine
C) neither A nor B (same for each) _______

37) A 2-kg ball is thrown at 3 m/s What is the ball's momentum?
A) 2 kg m/s
B) 3 kg m/s
C) 6 kg m/s
D) 9 kg m/s
E) none of the above _______

38) A 4-kg ball has a momentum of 12 kg m/s What is the ball's speed?
A) 3 m/s
B) 4 m/s
C) 12 m/s
D) 48 m/s
E) none of the above _______

39) A ball is moving at 4 m/s and has a momentum of 48 kg m/s What is the ball's mass?
A) 4 kg
B) 12 kg
C) 48 kg
D) 192 kg
E) none of the above _______

40) A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball that is initially at rest The bowling ball with its putty passenger will then be set in motion with a momentum of __
A) 0 kg m/s
B) 1 kg m/s
C) 2 kg m/s
D) 5 kg m/s
E) more than 5 kg m/s _______

Write True or False in the space provided.

41) Momentum is defined as an object's mass times its velocity _______

42) Impulse is defined as the force exerted on an object times the time it lasts _______

43) If the net external force acting on a system is zero, then the total momentum of the system is zero _______

44) When two objects collide and completely bounce apart with no lasting deformation or generation of heat, the collision is said to be elastic _______

45) When two objects collide and completely stick together, the collision is said to be inelastic _______

46) Impulses are normally smaller when bouncing takes place _______

47) Perfectly elastic collisions between large objects are uncommon in the everyday world _______

48) When a baseball player follows through when hitting the ball, the contact time with the ball is longer _______

49) Automobile dashboards that are padded lengthen the time of impact in case of a collision _______

50) If a net force acts on a system, the system's momentum will change _______

51) Momentum is a scalar quantity _______

On a separate sheet of paper, answer the following questions.

52) In terms of momentum change, explain why it is best to "give" when catching a baseball Provide other examples of situations in which you want to lengthen the impact time in a collision

53) An unfortunate bug splatters on the windshield of a moving car Describe the forces, impulses, momentum changes, and accelerations of both the bug and the car

54) A boy fires a Ping-Pong ball launcher Briefly describe the forces and impulses on the launcher and the ball Which has more momentum? Which is moving faster? Explain

55) What does it mean to say that momentum is conserved? Give at least two examples where momentum is conserved in a collision

56) A railroad diesel engine coasting at 10 km/h runs into a stationary flatcar The diesel weighs 4 times as much as the flatcar Assuming the cars couple together, how fast are they moving after the collision?

Answer the following questions in the space provided Show all work.

57) What is the average momentum of a 50-kg runner who covers 400 m in 50 s?_____

58) A cement truck of mass 16,000 kg moving at 15 m/s slams into a cement wall and comes to a halt What is the force of impact on the truck?_____

59) A 10-kg cement block moving horizontally at 2.0 m/s plows into a pillow and comes to a stop in 0.5 s What is the average impact force on the pillow? _____

60) A 8.0-kg blob of clay moving horizontally at 2.0 m/s hits a 4.0-kg blob of clay at rest What is the speed of the two blobs stuck together immediately after the collision?_____

61) A 40-kg football player leaps through the air to collide with and tackle a 60-kg player heading toward him, also in the air If the 40-kg player is heading to the right at 7.0 m/s, and the 60-kg player is heading toward the left at 3.0 m/s, what is the speed and direction of the tangled players?_____

62) A 5.0-kg blob of clay moving horizontally at 2.0 m/s has a head-on collision with a 6.0-kg blob of clay that moves toward it at 1.0 m/s What is the speed of the two blobs stuck together immediately after the collision?_____

63) A 10-kg bowling ball moving at 4.0 m/s bounces off a spring at about the same speed that it had before bouncing What is the change in momentum of the bowling ball?_____

64) A loaded freight car has 5 times as much mass as an empty freight car If the loaded car coasts at 2.0 m/s and collides with and attaches to the empty car at rest, what will be the speed of both cars after collision?_____

65) An 80-kg cart moving at 70 km/h collides head-on with an approaching 120-kg cart moving at 40 km/h (in the opposite direction) If the two carts stick together, what will be their speed?_____

66) A 30-kg girl and a 25-kg boy face each other on friction-free roller skates The girl pushes the boy, who moves away at a speed of 2.0 m/s What is the girl's speed?_____

67) A 100-kg free-floating astronaut fires 0.10 kg of gas at a speed of 50.0 m/s from her propulsion pistol What is the astronaut's recoil speed?_____

68) Assume that a 20-kg ball moving at 7.0 m/s strikes a wall perpendicularly and rebounds elastically at the same speed What is the amount of impulse given to the wall?_____