Energy Samples
MULTIPLE CHOICE. Choose the one alternative that
best completes the statement or answers the question.
1)
2)
3)
4)
A girl can easily lift an 80-N rock
with the help of a lever. When she
pushes down with 10 N of force, she
lifts the rock 0.1 meters. How far
does she move her arms to do this?
A) 1 m
B) 10 m
C) 0.8 m
D) 8 m
E) 0.1 m
A pulley has two supporting strands.
In order to use it to lift a load 1 meter,
the person pulling will have to pull a
distance of __________.
A) 1/2 m.
B) 2 m.
C) 1/4 m.
D) 1 m.
E) 4 m.
If an object has kinetic energy, then it
also must have __________.
A) momentum.
B) impulse.
C) force.
D) acceleration.
E) none of the above
Consider molecules of hydrogen gas
and molecules of heavier oxygen gas
that have the same kinetic energy.
The molecules with more speed are
__________.
A) oxygen.
B) Both have the same speed.
C) hydrogen.
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5)
The amount of potential energy
possessed by an elevated object is
equal to __________.
A) the work done in lifting it.
B) the distance it is lifted.
C) the value of the acceleration due
to gravity.
D) the force needed to lift it.
E) the power used to lift it.
6)
Power is defined as the __________.
A) work done times the time taken
to do that work.
B) force on an object times the
distance the object moves.
C) distance divided by the time
taken to move that distance.
D) force on an object divided by the
time the force acts.
E) work done on an object divided
by the time taken to do the work.
7)
If the velocity of a moving object
doubles, then what else doubles?
A) kinetic energy.
B) momentum.
C) acceleration.
D) all of the above
E) none of the above
8)
The unit of work is the __________.
A) joule.
B) watt.
C) newton.
D) second.
E) meter.
9)
The ratio of useful work output to
total work input is called the
__________.
A) mechanical advantage.
B) pivot point.
C) fulcrum.
D) efficiency.
E) lever arm.
13) If
Nellie Newton pushes an object
with twice the force for twice the
distance, she does __________.
A) eight times the work.
B) twice the work.
C) four times the work.
D) the same work.
14) As
a pendulum swings back and forth
__________.
A) at the lowest part of its swing, its
energy is all kinetic.
B) at the end points of its swing, its
energy is all potential.
C) kinetic energy is transformed into
potential energy.
D) potential energy is transformed
into kinetic energy.
E) all of the above
10) A
person on a roof throws one ball
downward and an identical ball
upward at the same speed. The ball
thrown downward hits the ground
with 100 J of kinetic energy. Ignoring
air friction, with how much kinetic
energy does the second ball hit the
ground?
A) 200 J
B) 100 J
C) Less than 100 J
D) More than 200 J
E) none of the above
15) The
ratio of output force to input
force of a simple machine is called the
__________.
A) mechanical advantage.
B) fulcrum.
C) pivot point.
D) efficiency.
E) lever arm.
11) How
much work is done on a 50-N
rock that you carry horizontally
across a 10-m room?
A) 5 J
B) 500 J
C) 50 J
D) 10 J
E) 0 J
16) An
object at rest may have
__________.
A) energy.
B) momentum.
C) velocity.
D) speed.
E) none of the above
12) A
machine puts out 100 watts of
power for every 1000 watts put into it.
The efficiency of the machine is
__________.
A) 110%.
B) 10%.
C) 90%.
D) 50%.
E) none of the above
17) Potential
energy is the energy an
object has because of its __________.
A) temperature.
B) speed.
C) density.
D) location.
E) size.
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18) All
simple machines ideally work on
the principle that __________.
A) impulse equals momentum
change.
B) force equals mass times
acceleration.
C) kinetic energy transforms into
potential energy.
D) work input equals work output.
E) total momentum before a
collision equals total momentum
after the collision.
22) An
arrow in a bow has 70 J of
potential energy. Assuming no loss of
energy due to heat, how much kinetic
energy will it have after it has been
shot?
A) 140 J
B) 70 J
C) 35 J
D) 0 J
E) 50 J
23) If
Kelly the skaterʹs speed increases so
he has twice the momentum, then his
kinetic energy increases by
__________.
A) two times.
B) eight times.
C) four times.
D) none of the above (KE remains
the same.)
19) If
you lift one load up two stories,
how much work do you do compared
to lifting one load up only one story?
A) Four times as much
B) One quarter as much
C) One half as much
D) Twice as much
E) The same amount
24) A
20) A
heavy object and a light object are
released from rest at the same height
and time in a vacuum. As they fall,
they have equal __________.
A) energies.
B) weights.
C) momenta.
D) all of the above
E) none of the above
pulley system can __________.
A) change the direction of a force.
B) multiply the force.
C) increase the amount of work
done.
D) Both A and B
E) Both B and C
21) A
job is done slowly, and an identical
job is done quickly. Both jobs require
the same amount of work but
different amounts of __________.
A) energy.
B) power.
C) both A and B
D) none of the above
25) An
object that has linear kinetic
energy must be __________.
A) at an elevated position.
B) moving.
C) at rest.
D) none of the above
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26) A
popular swinging apparatus
consists of an aligned row of identical
elastic balls suspended by strings so
they touch each other. When two balls
on one end are elevated and released,
they slam into the array of balls and
two balls pop out the other side. If
instead, one ball popped out with
twice the speed, this would be a
violation of the conservation of
__________.
A) energy.
B) both.
C) momentum.
29) If
you lift two loads up one story, how
much work do you do compared to
lifting just one load up one story?
A) One half as much
B) One quarter as much
C) The same amount
D) Twice as much
E) Four times as much
30) Energy
is changed from one form to
another with no net loss or gain.
A) Sometimes true
B) Always false
C) Always true
27) It
takes 40 J to push a large box 4 m
across a floor. Assuming the push is
in the same direction as the move,
what is the magnitude of the force on
the box?
A) 40 N
B) 4 N
C) 160 N
D) 10 N
E) none of the above
31) A
28) A
32) How
woman can lift barrels a vertical
distance of 1 meter or can roll them
up a 2 meter-long ramp to the same
elevation. If she uses the ramp, the
applied force required is __________.
A) four times as much.
B) the same amount.
C) half as much.
D) one quarter as much.
E) twice as much.
ball is thrown into the air with 100 J
of kinetic energy, which is
transformed to gravitational potential
energy at the top of its trajectory.
When it returns to its original level
after encountering air resistance, its
kinetic energy is __________.
A) more than 100 J.
B) Not enough information given.
C) less than 100 J.
D) 100 J.
much farther will a car traveling
at 100 km/s skid than the same car
traveling at 50 km/s?
A) Four times as far
B) The same distance
C) Half as far
D) Five times as far
E) Twice as far
33) Suppose
a moving car has 2000 J of
kinetic energy. If the carʹs speed
doubles, how much kinetic energy
would it then have?
A) 8000 J
B) 6000 J
C) 1000 J
D) 4000 J
E) 2000 J
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34) How
many joules of work are done
on an object when a force of 10 N
pushes it 5 m?
A) 2 J
B) 5 J
C) 50 J
D) 1 J
E) 10 J
39) About
how efficient is a typical
gasoline-burning car engine?
A) 5%
B) 100%
C) 30%
D) 70%
40) An
object that has kinetic energy must
be __________.
A) moving.
B) elevated.
C) falling.
D) at rest.
35) An
object that has kinetic energy must
have __________.
A) acceleration.
B) momentum.
C) a force applied to maintain it.
D) none of the above
41) A
frictionless inclined plane is 6 m
long and rests on a wall that is 2 m
high. How much force is needed to
push a block of ice weighing 300 N up
the plane?
A) 600 N
B) 200 N
C) 300 N
D) 50 N
E) 100 N
36) In
physics, work is defined as
__________.
A) force divided by time.
B) force times distance.
C) force times time.
D) force divided by distance.
E) distance divided by time.
42) Kinetic
energy of an object is equal to
__________.
A) its mass multiplied by its speed.
B) its mass multiplied by its
acceleration squared.
C) one half the product of its mass
times its speed.
D) one half the product of its mass
times its speed squared.
E) its mass multiplied by its
acceleration.
37) A
small economy car (low mass) and
a limousine (high mass) are pushed
from rest across a parking lot, equal
distances with equal forces. The car
that receives more change in kinetic
energy is the __________.
A) limousine.
B) small economy car.
C) same for each.
43) Cannonballs
38) The
are launched from an
airplane in the forward direction of
motion. The momentum of the
airplane will be __________.
A) unchanged.
B) decreased.
C) increased.
unit of power is the __________.
A) meter.
B) newton.
second.
D) watt.
E) joule.
C)
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44) How
much power is expended if you
lift a 50-N rock 10 meters in 1 second?
A) 50 W
B) 0 W
C) 10 W
D) 5 W
E) 500 W
49) How
much work is done on a 50-N
rock that you lift 10 m?
A) 0 J
B) 50 J
C) 500 J
D) 1 J
E) 10 J
45) How
50) Which
much power is required to do
100 J of work on an object in
2 seconds?
A) 0 W
B) 2 W
C) 100 W
D) 50 W
E) 200 W
has greater kinetic energy, a
car traveling at 30 km/h or a
half-as-massive car traveling at
60 km/h?
A) The 60-km/h car
B) Both have the same kinetic
energy.
C) The 30-km/h car
46) A
certain jack has a theoretical
mechanical advantage of 500.
However, due to frictional forces, the
actual mechanical advantage is only
100. What is the efficiency of the jack?
A) 50
B) 500
C) 1/5
D) 5
E) 50 000
47) Which
requires more work: lifting a
50-kg sack vertically 2 meters or
lifting a 25-kg sack vertically 4
meters?
A) Lifting the 50-kg sack
B) Lifting the 25-kg sack
C) Both require the same amount of
work.
48) A 10-N object
moves at 1 m/s. Its
kinetic energy is __________.
A) 10 J.
B) 0.5 J.
C) 1 J.
D) more than 10 J.
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Answer Key
Testname: PHYSICS ENERGY SAMPLES
1) C
24) E
Diff: 0
Diff: 0
2) B
25) B
Diff: 0
Diff: 0
3) A
26) A
Diff: 0
Diff: 0
4) C
27) D
Diff: 0
Diff: 0
5) A
28) C
Diff: 0
Diff: 0
6) E
29) D
Diff: 0
Diff: 0
7) B
30) C
Diff: 0
Diff: 0
8) A
31) C
Diff: 0
Diff: 0
9) D
32) A
Diff: 0
Diff: 0
10) B
33) A
Diff: 0
Diff: 0
11) E
34) C
Diff: 0
Diff: 0
12) B
35) B
Diff: 0
Diff: 0
13) C
36) B
Diff: 0
Diff: 0
14) E
37) C
Diff: 0
Diff: 0
15) A
38) D
Diff: 0
Diff: 0
16) A
39) C
Diff: 0
Diff: 0
17) D
40) A
Diff: 0
Diff: 0
18) D
41) E
Diff: 0
Diff: 0
19) D
42) D
Diff: 0
Diff: 0
20) D
43) B
Diff: 0
Diff: 0
21) B
44) E
Diff: 0
Diff: 0
22) B
45) D
Diff: 0
Diff: 0
23) C
46) C
Diff: 0
Diff: 0
7
Answer Key
Testname: PHYSICS ENERGY SAMPLES
47) C
Diff: 0
48) B
Diff: 0
49) C
Diff: 0
50) A
Diff: 0
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