Transcript Physics Quiz

Physics Review Quiz
Motion and Forces; Energy
Jan. 2012
1. Newton’s First Law says that when
forces are _____________, no
acceleration occurs.
a. equal
b. constant
c. balanced
d. removed
2. According to Newton’s Second Law,
acceleration is directly proportional
to__________ and inversely
proportional to _______________.
a.speed; time
b. distance; force
c. force; time
d. force; mass
3. A 3-kg mass is accelerated at a rate
of 12 m/s2. What amount of force
caused the acceleration?
a.0.25 N
b. 4 N
c. 9 N
d. 15 N
e. 36 N
4. Two equal masses are accelerated
by forces of 2 N and 4 N. The second
mass accelerates
a.the same as the first, since all
masses accelerate at the same rate
b. twice as fast as the first, since it has
twice the force applied
c. four times as fast as the first,
because 2 squared is 4
5. A baseball player strikes the ball with
his bat. The force on the ball
a. is equal to the force on the bat
b. is smaller than the force on the bat
c. is larger than the force on the bat
6. The momentum of a 5-kg mass
moving at 3 m/s is
a.1.67 m/s
b. 15 kg·m/s
c. 0.6 kg·m/s
d. 0.6 m/s2
7. The momentum of a 1-kg mass after
accelerating from rest at 3 m/s2 for 4
seconds is
a.12 m/s
b. 12 kg·m/s
c. 0.75 kg·m/s2
d. 12 N
8. It is impossible for a marshmallow to
have as much momentum as a jumbo
jet.
a.true
b. false
9. To change the momentum of an
object, you must apply an impulse.
Impulse is
a.the product of force and distance
b. the product of force and velocity
c. the product of time and force
d. the sum of force and distance
10. Impulse is equal to
a.change in potential energy
b. change in kinetic energy
c. change in momentum
d. both a and b
11. To change the momentum of an
object from 10 kg·m/s to 14 kg·m/s, a
force of 8 N must be applied for
a. 140 seconds
b. 2 seconds
c. one-half second
d. 80 seconds
12. A 75-kg figure skater gliding across
the ice at 4 m/s comes to a complete
stop after 20 seconds. The friction on
his skates must have been
a. 300 N
b. 80 N
c. 15 N
d.1500 N
13. A billiard ball going 3 m/s collides with
an identical ball at rest. The first ball
comes to a complete stop after the
collision. The second ball
a.moves away at 3 m/s, but in the other
direction from the direction the first ball
was moving
b. moves away at an angle, less than 3 m/s
c. has the same velocity as the first ball had
before the collision
14. An object is in equilibrium if it is
a.in free fall
b. moving at constant speed
c.at rest with no net force acting on it
d. supported by a normal force
e. all the above
15. The property of resisting changes in
motion in the absence of an outside
force is called
a.inertia
b. constant velocity
c. equilibrium
d. negativism
16. The support force of a table on a
book is also called the normal force
because
a. all tables have it
b. all books have it
c. its just ordinary
d. it acts upward
e. it acts perpendicular to the table
17. An arrow with a momentum of 0.75
kg·m/s hits a stationary target and
sticks. Immediately after the arrow
hits, the arrow and target
a.have zero momentum
b. have –0.75 kg·m/s momentum
c. have 0.75 kg·m/s momentum
d. there’s no way to tell
18. Two identical blobs of putty move
towards each other at the same
speed and stick together when they
hit. Immediately after the collision,
their combined momentum is
a.zero
b. the same as it was before
c. twice the individual momentum
d. both a and b
19. A 100 watt engine is used to pull a
10-kg load up to the roof of a 30
meter high building. How long did it
take?
a. 6.32 minutes
b. 29.4 seconds
c. 30,000 seconds
d. 300 seconds
20. An object having 8,000 joules of
potential energy falls out of a window.
When it hits the sidewalk, its potential
energy
a.is still 8,000 joules
b. is zero
c. instantly changes to kinetic energy
d. both b and c
e. both a and c
21. A 2-kg mass with a 3 m/s velocity
has a kinetic energy of
a. 6 kg·m/s
b. 6 joules
c. 1.5 joules
d. 9 joules
e. 9 kg·m/s
22. Doing work on an object changes
a. where it is
b. how fast it’s moving
c. its total energy
d. its mass
e. its value
23. Momentum is conserved in
a. elastic collisions
b. inelastic collisions
c. all collisions
d. small mason jars
24. Kinetic energy is conserved in
a. inelastic collisions
b. elastic collisions
c. all collisions
d. large mason jars
25. A man carries a 2-kg rock from a 10
meter high hill to a 20 meter high hill.
The potential energy of the rock
a. doubled
b. quadrupled
c. did not change
d. changed to kinetic energy
26. How much work has to be done to
stop a 10-kg object moving with a
velocity of –10 m/s?
a. 500 joules
b. 100 newtons
c. –100 newtons
d. –100 joules
e. –1,000 joules
Check your answers. Write the number
correct on your paper and turn it in.
1. c
7. b
13. c
2. d
8. b
14. c
3. e
9. c
15. a
4. b
10. c
16. e
5. a
11. c
17. c
6. b
12. c
18. d
19. b
20. b
21. d
22. c
23. c
24. b
25. a
For 20 points extra credit in the quiz
column, complete this problem for
homework, showing all your work. Copy
it now on a new sheet of paper.
26. How much work has to be done to
stop a 10-kg object moving with a
velocity of –10 m/s?
Turn in your
quiz and