Physics 131 Test/Exam Problems: Impulse and Momentum
1) A student is initially standing still on a frictionless ice rink. Her friend throws a Frisbee directly toward her. After which of the following cases will the student be sliding on the ice with the greatest speed? (b)
(a) The student catches and holds on to the Frisbee.
(b) The student catches the Frisbee and then throws it back to her friend.
(c) The student catches the Frisbee and then drops it.
2) A bullet having an initial velocity of 300 m/s in the +x direction penetrates an initially stationary pop can of mass 100 gm and emerges in the other side with a final velocity of
200 m/s in the +x direction. The velocity of the pop can after the collision is 5 m/s, also in the +x direction. Assume the pop can slides on a horizontal frictionless surface. What is the mass of the bullet? (b)
(a) 2 gm
(b) 5 gm
(c) 12 gm
(d) 21 gm
(e) 25 gm

3) Which one of the following statements describing the above collision is true: (a)
(a) The momentum of the system in the x direction is conserved but the total mechanical energy of the system is not.
(b) The total mechanical energy of the system is conserved but the momentum of the system in the x direction is not.
(c) Both the momentum of the system in the x direction and the total mechanical energy of the system are conserved.
4) A bomb is initially at rest when it suddenly explodes into three pieces. A 5-kg piece goes north at 6 m/s, and a 2-kg piece goes east at 20 m/s. The speed of the third piece is 25 m/s. What is the mass of the third piece? (d)
(a) 1.2 kg
(b) 2.5 kg
(c) 3.6 kg
(d) 2.0 kg
(e) 4.8 kg
5) To test an aircraft window, a cannon is used to shoot dead chickens at it to simulate midair collisions with birds. All chickens have the same mass and are shot with the same velocity, but since they come from a local supermarket some chickens are frozen (hard) and some chickens are thawed (soft). Which chickens are more likely to break the window? (a) Why?
(a) Frozen chickens are more likely to break the window.
(b) Thawed chickens are more likely to break the window.
(c) Frozen and thawed chickens are equally likely to break the window.

The next 5 problems refer to the same situation
6) Two blocks slide towards each other on a frictionless surface. Block 1 has mass 6 kg and slides to the right with speed 15 m/s. Block 2 of unknown mass slides to the left with speed 15 m/s. The blocks collide, stick together and move to the right with velocity v f
= 5 m/s. Compare the magnitude of the net impulse on block 1, I
1
, with the magnitude of the net impulse on block 2, I
2
, during the collision. (b)
(a) I
1
> I
2
(b) I
1
= I
2
(c) I
1
< I
2
7) What is M
2
, the mass of block 2? (b)
(a) M
2
= 0.67 kg
(b) M
2
= 3.0 kg
(c) M
2
= 6.0 kg
(d) M
2
= 18 kg
(e) M
2
= 54 kg
8) What is the KE
1f
, kinetic energy of block 1 after the collision? (d)
(a) KE
1f
= 0 J
(b) KE
1f
= 30 J
(c) KE
1f
= 50 J
(d) KE
1f
= 75 J
(e) KE
1f
= 100 J

9) What is the net impulse I
2
on block 2 during the collision? (d)
(a) I
2
= 12 Ns
(b) I
2
= 30 Ns
(c) I
2
= 24 Ns
(d) I
2
= 60 Ns
(e) I
2
= 72 Ns
10) Which of the following statements best describes what happens to the two-block system during the collision? (c)
(a) Total momentum and kinetic energy are both conserved.
(b) Kinetic energy is conserved but total momentum is not.
(c) Total momentum is conserved but kinetic energy is not.
11) You are on the crew of the space shuttle performing extra-vehicular activity. You are slowly drifting away from the shuttle at a constant speed of 5 m/s. You decide that you are getting dangerously far from the shuttle and want to reverse your direction. You decide to throw the 10 kg tool kit you are carrying. In what direction should you throw the tool kit in order to achieve your desire to move toward the shuttle. (b)
(a) Toward the shuttle
(b) Away from the shuttle
(c) It makes no difference

12) A constant net force F is applied to block 1 (mass=M) and block 2 (mass=2M), both initially at rest, for the same amount of time
 t. Which block will end up with the higher momentum? (c)
(a) block 1
(b) block 2
(c) They end up with the same momentum.
13) Block A of mass M initially moves in the +x direction with velocity v. Block B of mass
3M is initially at rest. The two blocks collide, but do not stick together. After the collision
Block B moves in the +x direction with velocity v/2. The surface is frictionless.
What is the momentum of block B after the collistion?(c)
(a) Mv/2
(b) Mv
(c) 3Mv/2
(d) 2Mv
(e) 3Mv
14) What is the velocity of block A after the collision?(b)
(a) v/2 in +x direction
(b) v/2 in –x direction
(c) 0

15) A ball of mass 0.15 kg is thrown directly against a wall with an initial speed of 18 m/s. It bounces straight backward (in the opposite direction) with a final speed of 10 m/s. The contact time between the ball and wall is 1.5 x 10
-3
s. What is the magnitude of the average force exerted on the ball by the wall during the contact time? (a)
(a) 2800 N
(b) 5100 N
(c) 6667 N
(d) 12000 N
(e) 18667 N
16) Block 1 of mass 2 kg initially moves in the +x direction with velocity 4 m/s. Block 2 of mass 1 kg initially moves in the –x direction with velocity 6 m/s. The two blocks collide and stick together. In what direction do the two blocks move after the collision? (a)
(a) +x
(b)
–x
(c) They are at rest.
17) An object of mass M = 5 kg is moving horizontally in a straight line at a speed of 6 m/s.
A force of 100 N is applied over a short period of time such that the speed of the object increases to 10 m/s.
What is the time period over which the force was applied? (d)
(a) 10 s
(b) 0.35 s
(c) 0.15 s
(d) 0.2 s
(e) 5 s

18) An automobile of mass 1200 kg moving at 1.5 m/s collides with a lamp post and comes to rest. The collision takes 0.1 s.
What is the total impulse delivered to the automobile? (d)
(a) 1100 kg-m/s
(b) 1200 kg-m/s
(c) 1600 kg-m/s
(d) 1800 kg-m/s
(e) 2400 kg-m/s
19) A rocket is moving at a speed V
0
and suddenly breaks into two pieces of equal mass.
They fly off with velocities V
1
and V
2
, as shown in the drawing below. Which of the following equations describes the relation between the magnitude of V
1
and V
2
? (d)
(a) V
1
= V
2
(b) V
1
= (1.2) V
2
(c) V
1
= (1.3) V
2
(d) V
1
= (1.7) V
2
(e) V
1
= (1.9) V
2

20) Two balls approach each other on a flat frictionless surface. As in the picture below, ball
A heads north with a velocity of 5 m/s, while ball B heads due east with a velocity of 2 m/s. Ball A has a mass of 3 kg, and ball B has a mass of 5 kg. When the two balls collide they stick together. Determine the final speed and angle

that the balls have after their collision. (2.25 m/s, 56.3 degrees)
21) In order to convert a tough split in bowling it is necessary to strike the pin with a glancing blow as in the picture. Assume the bowling ball has velocity of 12 m/s initially. And assume the pin has a velocity of 15 m/s after it is hit. What is the velocity of the bowling ball afterwards and what angle is moving at? Assume the bowling ball is five times the mass of the pin. (11.66 m/s, 14.4

)