Name: ___________________________
Momentum-Impulse Review
Date: ________
Period: ______
A ___ 1.Which of the following has the greatest momentum?
a.
b.
c.
d.
a tortoise with a mass of 275 kg moving at a velocity of 0.55 m/s
a hare with a mass of 2.7 kg moving at a velocity of 7.5 m/s
a turtle with a mass of 91 kg moving at a velocity of 1.4 m/s
a roadrunner with a mass of 1.8 kg moving at a velocity of 6.7 m/s
A _____ 2. A person sitting in a chair with wheels stands up, causing the chair to roll backward across the floor. The
momentum of the chair
a.
b.
c.
d.
was zero while stationary and increased when the person stood.
was greatest while the person sat in the chair.
remained the same.
was zero when the person got out of the chair and increased while the person sat.
D _____ 3. A 0.2 kg baseball is pitched with a velocity of 40 m/s and is then batted to the pitcher with a velocity of 60
m/s. What is the magnitude of change in the ball’s momentum?
a.
b.
c.
d.
2 kgm/s
8 kgm/s
4 kgm/s
20 kgm/s
B _____ 4. Which of the following statements about the conservation of momentum is not correct?
a.
b.
c.
d.
Momentum is conserved for a system of objects pushing away from each other.
Momentum is not conserved for a system of objects in a head-on collision.
Momentum is conserved when two or more interacting objects push away from each other.
The total momentum of a system of interacting objects remains constant regardless of forces between
the objects.
B _____ 5. Two balls of dough collide and stick together. Identify the type of collision.
a.
b.
c.
d.
Elastic
Inelastic – together at the end
Inelastic – together at the beginning
Conserved
SHORT ANSWER
6. Which has more momentum, a supertanker tied securely at the dock or a falling raindrop? Why?
Raindrop has more momentum because it is moving. Supertanker has no velocity  no momentum.
7. Is the momentum of a car traveling south different from that of an identical car moving north at the same
speed? Explain.
The momentums are different – one is positive and one is negative.
8. When you jump off something like a table you let your legs bend at the knees when you strike the floor. Explain
why you would do this.
When you bend your knees, you are increasing the time you are changing your momentum, and therefore decreasing
the force exerted on your body by the floor.
9. Why are today’s vehicles designed with crumple zones?
The crumple zone is designed to increase the time of collision (where you change your momentum), and therefore
decreasing the force exerted on the car saving your life.
10. To catch a fast moving baseball barehanded should your hand be moving or should it be still at the time of
contact? Why?
Your hand should be moving to increase the time in which you change the baseball’s momentum, therefore
decreasing the force exerted on your hand (so it doesn’t hurt as much).
11. A boxer being hit by a punch tries to move with the punch for best results, whereas a karate expert delivers a
blow to bricks in a short time for best results. Is this a contradiction? Explain.
A boxer wants to increase the time of the punch so it hurts his face less (less force exerted on him).
The karate expert wants to increase the force to break the bricks, so she has to decrease the time.
12. A baseball pitcher’s first pitch is a fastball, moving at high speed. The pitcher’s second pitch—with the same
ball—is a changeup, moving more slowly. Which pitch is harder for the catcher to stop? Explain your answer in
terms of momentum.
Fastball will be harder to stop, because it has more velocity and therefore more momentum to change.
13. Is it possible for a spaceship traveling with constant velocity to experience a change in momentum? Explain your
answer.
It is possible if you change the mass of the ship – for example, throwing something off of the ship.
PROBLEM SOLVING
14. What velocity must a 1340 kg car have in order to have the same momentum as a 2680 kg truck traveling at a
velocity of 15 m/s to the west?
p = 40,200 kgm/s
40,200 = (1340kg)v
v = 30 m/s
15. A 0.060 kg tennis ball moves at a velocity of 12 m/s. The ball is struck by a racket, causing it to rebound in the
opposite direction at a speed of 18 m/s. What is the impulse of the racket on the ball?
BEFORE
AFTER
Picture
Picture
Tennis ball moving at 12 m/s
Tennis ball moving in OPPOSITE DIRECTION at 18 m/s
TOK
TOK
m1 = 0.060 kg
v1 = 12 m/s
m1 = 0.060 kg
v1f = -18 m/s
Bar Chart
p1
p2
J
p1f
p2f
Equation
m1v1 + F∆t = m1v1f
F∆t = -1.8 kgm/s
16. A train with a mass of 1,800 kg is moving at 15 m/s when the engineer applies the brakes. If the braking force is
constant at 35,000 N, how long does it take the train to stop?
BEFORE
AFTER
Picture
Picture
Train moving at 15 m/s
Train stopped
TOK
TOK
m1 = 1,800 kg
v1 = 15 m/s
F = 35,000 N
m1 = 1,800 kg
v1f = 0 m/s
Bar Chart
p1
p2
J
p1f
p2f
Equation
m1v1 + F∆t = m1v1f
∆t = 0.77 s
17.An astronaut with a mass of 85 kg is outside a space capsule when the tether line breaks and he is stranded at rest
out in space. To return to the capsule, the astronaut throws a 2.0 kg wrench away from the capsule at a speed of 14
m/s. At what speed does the astronaut move toward the capsule?
BEFORE
AFTER
Picture
Picture
Astronaut and wrench at rest
Astronaut and wrench travelling in different directions
TOK
TOK
m1 = 85 kg
vi = 0 m/s
m2 = 2.0 kg
m1 = 85 kg
v1f = ? m/s
m2 = 2.0 kg
v2f = 14 m/s
Bar Chart
p1
p2
0
J
0
p1f
p2f
0
Equation
(m1 + m2) vi = m1v1f + m2v2f
v1f = -0.33 m/s
18.A 0.10 kg toy car initially travelling at 0.195 m/s makes a head-on collision with a 0.15 kg stationary truck. The final
velocity of the 0.10 kg toy car after the collision is 0.045 m/s. Calculate the final velocity of the 0.15 kg toy truck
after the collision.
BEFORE
AFTER
Picture
Picture
Toy car headed toward toy truck
Toy car and toy truck bounce off of each other
TOK
TOK
m1 = 0.10 kg
vi = 0.195 m/s
m2 = 0.15 kg
v2f = 0 m/s
Bar Chart
m1 = 0.10 kg
v1f = -0.045 m/s
m2 = 0.15 kg
v2f = ? m/s
p1
p2
0
J
p1f
p2f
0
Equation
m1v1 + m2v2 = m1v1f + m2v2f
v2f = 0.16 m/s
20.A 90 kg halfback runs 8 m/s in the positive direction and is tackled by a 120 kg opponent running in the negative
direction at 4 m/s. Just after the tackle, both players move in the positive direction. Calculate the final velocity of
both players together.
BEFORE
AFTER
Picture
Picture
Halfback runs and collides with opponent
traveling in opposite direction
Both players move in positive direction
TOK
TOK
m1 = 90 kg
vi = 8 m/s
m2 = 120 kg
v2 = -4 m/s
m1 =90kg
vf = ? m/s
m2 = 120 kg
Bar Chart
p1
p2
J
p1f
0
Equation
m1v1 + m2v2 = (m1+ m2)v2f
v2f = 1.14 m/s
+
p2f