Clickers Ch. 6

1. Clicker Questions
Chapter 6:
Momentum
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2. When a farmer throws a 3-kg pumpkin at a
speed of 4 m/s onto a compost pile, the
pumpkin's momentum just before hitting the pile
is
a) 0 kg•m/s.
b) 5 kg•m/s.
c) 7 kg•m/s.
d) 12 kg•m/s.
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3. When a farmer throws a 3-kg pumpkin at a
speed of 4 m/s onto a compost pile, the
pumpkin's momentum just before hitting the pile
is
a) 0 kg•m/s.
b) 5 kg•m/s.
c) 7 kg•m/s.
d) 12 kg•m/s.
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4. Compared with the momentum of a 200-lb man
running 10 mi/h, the momentum of a 2000-lb
car moving 1 mph is
a) zero.
b) the same.
c) greater.
d) less.
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5. Compared with the momentum of a 200-lb man
running 10 mi/h, the momentum of a 2000-lb
car moving 1 mph is
a) zero.
b) the same.
c) greater.
d) less.
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6. A lunar vehicle is tested on Earth at a speed of
10 km/h. When it travels at the same speed on
the Moon, its momentum is
a) the same.
b) less.
c) more.
d) zero.
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7. A lunar vehicle is tested on Earth at a speed of
10 km/h. When it travels at the same speed on
the Moon, its momentum is
a) the same.
b) less.
c) more.
d) zero.
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8. When both the force and time of contact are
doubled, the impulse on an object is
a) unchanged.
b) doubled.
c) quadrupled.
d) decreased.
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9. When both the force and time of contact are
doubled, the impulse on an object is
a) unchanged.
b) doubled.
c) quadrupled.
d) decreased.
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10. Your friend says that impulse equals momentum.
Your friend's statement is not correct, and the
missing word is
a) work.
b) acceleration.
c) speed or velocity.
d) change.
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11. Your friend says that impulse equals momentum.
Your friend's statement is not correct, and the
missing word is
a) work.
b) acceleration.
c) speed or velocity.
d) change.
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12. If a car comes to a full stop when hitting a
haystack and when hitting a stone wall, the
change in momentum is greater for hitting the
a) haystack.
b) stone wall.
c) Same momentum change in both cases.
d) None of the above.
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13. If a car comes to a full stop when hitting a
haystack and when hitting a stone wall, the
change in momentum is greater for hitting the
a) haystack.
b) stone wall.
c) Same momentum change in both cases.
d) None of the above.
Explanation:
Although the change in momentum is the same for
both cases, the forces involved are quite different!
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14. A 1-kg ball has the same speed as a 10-kg ball.
Compared with the 1-kg ball, the 10-kg ball has
a) less momentum.
b) the same momentum.
c) 10 times as much momentum.
d) 100 times as much momentum.
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15. A 1-kg ball has the same speed as a 10-kg ball.
Compared with the 1-kg ball, the 10-kg ball has
a) less momentum.
b) the same momentum.
c) 10 times as much momentum.
d) 100 times as much momentum.
Explanation:
Let the definition mv guide your thinking.
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16. Which of the following equations most directly
illustrates the safety value of automobile
airbags?
a) F = ma.
b) Ft = ∆(mv).
c) d = 1/2 at2.
d) v = gt.
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17. Which of the following equations most directly
illustrates the safety value of automobile
airbags?
a) F = ma.
b) Ft = ∆(mv).
c) d = 1/2 at2.
d) v = gt.
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18. A ball is tossed into a bale of hay and comes to
a stop. If instead, it comes to a stop when
hitting a sticky solid wall, the impulse needed to
stop it is
a) less.
b) the same.
c) more.
d) zero.
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19. A ball is tossed into a bale of hay and comes to
a stop. If instead, it comes to a stop when
hitting a sticky solid wall, the impulse needed to
stop it is
a) less.
b) the same.
c) more.
d) zero.
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20. When a falling object bounces as it hits the
ground
a) the impulse on it is greater than for stopping it.
b) its change in momentum is greater than for stopping.
c) Both of these.
d) None of these.
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21. When a falling object bounces as it hits the
ground
a) the impulse on it is greater than for stopping it.
b) its change in momentum is greater than for stopping.
c) Both of these.
d) None of these.
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22. When you jump from an elevated position to
the ground below, the force you experience
when landing does NOT depend on
a) the jumping height.
b) the softness or hardness of the ground.
c) how much you bend your knees.
d) your attitude about jumping.
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23. When you jump from an elevated position to
the ground below, the force you experience
when landing does NOT depend on
a) the jumping height.
b) the softness or hardness of the ground.
c) how much you bend your knees.
d) your attitude about jumping.
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24. Nets used to catch falling boulders on the side
of rocky hillside roadways are more effective
than rigid fences because their breakage is
reduced by
a) less impulse of falling rocks.
b) less momentum of falling rocks.
c) more time to change the momentum of falling
rocks.
d) less time to change the momentum of falling rocks.
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25. Nets used to catch falling boulders on the side
of rocky hillside roadways are more effective
than rigid fences because their breakage is
reduced by
a) less impulse of falling rocks.
b) less momentum of falling rocks.
c) more time to change the momentum of falling
rocks.
d) less time to change the momentum of falling rocks.
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26. Standing still on a skateboard, you catch a ball
tossed horizontally to you. The mass of the ball
is one-tenth your mass. Compared with the
speed of the caught ball, the speed that both
you and the caught ball acquire is
a) the same.
b) one-tenth as much.
c) 10 times as much.
d) 100 times as much.
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27. Standing still on a skateboard, you catch a ball
tossed horizontally to you. The mass of the ball
is one-tenth your mass. Compared with the
speed of the caught ball, the speed that both
you and the caught ball acquire is
a) the same.
b) one-tenth as much.
c) 10 times as much.
d) 100 times as much.
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28. When Jake tosses a ball while standing still on
his skateboard, he and his skateboard recoil. If
he goes through the motions of tossing the ball,
but doesn't toss it, his net recoil will ideally be
a) the same as if he threw the ball.
b) almost as much as if he threw the ball.
c) very small.
d) zero.
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29. When Jake tosses a ball while standing still on
his skateboard, he and his skateboard recoil. If
he goes through the motions of tossing the ball,
but doesn't toss it, his net recoil will ideally be
a) the same as if he threw the ball.
b) almost as much as if he threw the ball.
c) very small.
d) zero.
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30. When you say momentum is conserved, you
mean that
a) when an impulse acts on an object, its momentum
will change.
b) momentum can be stored.
c) when external impulses don't occur, a system's
momentum remains the same before and after
an interaction.
d) when two objects collide, the mass and velocity of
each object will not change.
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31. When you say momentum is conserved, you
mean that
a) when an impulse acts on an object, its momentum
will change.
b) momentum can be stored.
c) when external impulses don't occur, a system's
momentum remains the same before and after
an interaction.
d) when two objects collide, the mass and velocity of
each object will not change.
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32. In the absence of external forces, momentum is
conserved in
a) an elastic collision.
b) an inelastic collision.
c) either an elastic or an inelastic collision.
d) neither an elastic nor an inelastic collision.
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33. In the absence of external forces, momentum is
conserved in
a) an elastic collision.
b) an inelastic collision.
c) either an elastic or an inelastic collision.
d) neither an elastic nor an inelastic collision.
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34. A big fish coasts up to and swallows a small
fish at rest. Right after lunch, the speed of the
big fish is
a) the same as before.
b) less than before.
c) more than before.
d) zero.
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35. A big fish coasts up to and swallows a small
fish at rest. Right after lunch, the speed of the
big fish is
a) the same as before.
b) less than before.
c) more than before.
d) zero.
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36. A big fish swims up on and swallows a small
fish at rest. Right after lunch, the momentum of
the big fish is
a) the same as before.
b) less than before.
c) more than before.
d) zero.
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37. A big fish swims up on and swallows a small
fish at rest. Right after lunch, the momentum of
the big fish is
a) the same as before.
b) less than before.
c) more than before.
d) zero.
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38. a) a little less than one unit.
b) one unit.
c) more than one unit.
d) much less than one unit.
A piece of clay moving with one unit of
momentum strikes and sticks to a heavy
bowling ball initially at rest. After the clay sticks,
both the clay and ball ideally move with a
combined momentum of
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39. A piece of clay moving with one unit of
momentum strikes and sticks to a heavy
bowling ball initially at rest. After the clay sticks,
both the clay and ball ideally move with a
combined momentum of
a) a little less than one unit.
b) one unit.
c) more than one unit.
d) much less than one unit.
Explanation:
Straight logic; the momentum before the interaction was one unit, and
in the absence of external forces remains one unit after the interaction.
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40. A pair of spiral galaxies collide and merge to
form one larger elliptical galaxy. Astronomers
assume that the momentum of the new elliptical
galaxy is
a) equal to the sum of the momenta of two spiral
galaxies.
b) equal to the difference in momenta of the two spiral
galaxies.
c) the same as the momentum of the more massive
spiral galaxy.
d) zero.
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41. A pair of spiral galaxies collide and merge to
form one larger elliptical galaxy. Astronomers
assume that the momentum of the new elliptical
galaxy is
a) equal to the sum of the momenta of two spiral
galaxies.
b) equal to the difference in momenta of the two spiral
galaxies.
c) the same as the momentum of the more massive
spiral galaxy.
d) zero.
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