Download Assessment

Momentum and Collisions
Chapter 6 Study Guide
MULTIPLE CHOICE
In the space provided, write the letter of the term or phrase that best completes
each statement or best answers each question.
_____ 1. 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.
_____ 2. A child with a mass of 23 kg rides a bike with a mass of 5.5 kg at a
velocity of 4.5 m/s to the south. Compare the momentum of the child
with the momentum of the bike.
a. Both the child and the bike have the same momentum.
b. The bike has a greater momentum than the child.
c. The child has a greater momentum than the bike.
d. Neither the child nor the bike has momentum.
_____ 3. A roller coaster climbs up a hill at 4 m/s and then zips down the hill at
30 m/s. The momentum of the roller coaster
a. is greater up the hill than down the hill.
b. is greater down the hill than up the hill.
c. remains the same throughout the ride.
d. is zero throughout the ride.
_____ 4. 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 produces a large change in the object’s momentum.
Chapter Test A continued
_____ 5. A ball with a momentum of 4.0 kgm/s hits a wall and bounces straight
back without losing any kinetic energy. What is the change in the ball’s
momentum?
a. 8.0 kgm/s
c. 0.0 kgm/s
b. 4.0 kgm/s
d. 8.0 kgm/s
_____ 6. The impulse experienced by a body is equivalent to the body’s change in
a. velocity.
c. momentum.
b. kinetic energy.
d. force.
_____ 7. A 75 kg person walking around a corner bumped into an 80 kg person
who was running around the same corner. The momentum of the 80 kg
person
a. increased.
c. remained the same.
b. decreased.
d. was conserved.
_____ 8. Two skaters stand facing each other. One skater’s mass is 60 kg, and the
other’s mass is 72 kg. If the skaters push away from each other without
spinning,
a. the lighter skater has less momentum.
b. their momenta are equal but opposite.
c. their total momentum doubles.
d. their total momentum decreases.
_____ 9. In a two-body collision,
a. momentum is always conserved.
b. kinetic energy is always conserved.
c. neither momentum nor kinetic energy is conserved.
d. both momentum and kinetic energy are always conserved.
_____ 10. The law of conservation of momentum states that
a. the total initial momentum of all objects interacting with one another
usually equals the total final momentum.
b. the total initial momentum of all objects interacting with one another
does not equal the total final momentum.
c. the total momentum of all objects interacting with one another is zero.
d. the total momentum of all objects interacting with one another remains
constant regardless of the nature of the forces between the objects.
_____ 11. Two objects stick together and move with a common velocity after
colliding. Identify the type of collision.
a. elastic
c. inelastic
b. perfectly elastic
d. perfectly inelastic
_____ 12. Two billiard balls collide. Identify the type of collision.
a. elastic
c. inelastic
b. perfectly elastic
d. perfectly inelastic
_____ 13. In an inelastic collision between two objects with unequal masses,
a. the total momentum of the system will increase.
b. the total momentum of the system will decrease.
c. the kinetic energy of one object will increase by the amount that the
kinetic energy of the other object decreases.
d. the momentum of one object will increase by the amount that the
momentum of the other object decreases.
_____ 14. A billiard ball collides with a stationary identical billiard ball in an
elastic head-on collision. After the collision, which of the following is
true of the first ball?
a. It maintains its initial velocity.
b. It has one-half its initial velocity.
c. It comes to rest.
d. It moves in the opposite direction.
SHORT ANSWER
15. As a bullet travels through the air, it slows down due to air resistance. How
does the bullet’s momentum change as a result?
_________________________________________________________________
_________________________________________________________________
16. A student walks to class at a velocity of 3 m/s. To avoid walking into a door as
it opens, the student slows to a velocity of 0.5 m/s. Now late for class, the
student runs down the corridor at a velocity of 7 m/s. At what point in this
scenario does the student have the least momentum?
_________________________________________________________________
_________________________________________________________________
17. How can a small force produce a large change in momentum?
_________________________________________________________________
_________________________________________________________________
18. Two billiard balls of equal mass are traveling straight toward each other with
the same speed. They meet head-on in an elastic collision. What is the total
momentum of the system containing the two balls before the collision?
_________________________________________________________________
Chapter Test A continued
PROBLEM
19. Compare the momentum of a 6160 kg truck moving at 3.00 m/s to the
momentum of a 1540 kg car moving at 12.0 m/s.
20. A ball with a mass of 0.15 kg and a velocity of 5.0 m/s strikes a wall and
bounces straight back with a velocity of 3.0 m/s. What is the change in
momentum of the ball?
Physics Ch. 6 Study Guide
Momentum and Collisions
CHAPTER 6 STUDY GUIDE
1.
2.
3.
4.
5.
c
c
b
c
a
Given
pi  4.0 kg  m/s
pf  4.0 kg  m/s
Solution
p  pf  pi  (4.0 kg  m/s) 
4.0 kg  m/s  8.0 kg  m/s


6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
19. They have the same momentum.
(1.85  10 4 kg  m/s)
Given
m1  6160 kg


c
b
b
a
d
d
a
d
c

The bullet’s momentum decreases as its
speed decreases.
16. The student has the least momentum when
dodging the opening door.
17. A small force can produce a large change in
momentum if the force acts on an object for 
a long period of time.
18. zero
v 1  3.00 m/s
m2  1540 kg
v 2  12.0 m/s
Solution
p1 = m1v1 = (6160 kg)(3.00 m/s)
=1.85  104 kgm/s
p2 = m2v2 = (1540 kg)(12.0 m/s)
=1.85  104 kgm/s
p1 = p2
20. 1.2 kg  m/s
Given
m  0.15 kg
v i  5.0 m/s
v f  3.0 m/s
Solution
p  m(v f  v i ) 
(0.15 kg)( 3.0 m/s  5.0 m/s) 
1.2 kg  m/s