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Work & Energy review sheet
Name:
1.
2.
Date:
How much work is required to lift a 2-kilogram
mass to a height of 10 meters?
A.
5 joules
B.
C.
100 joules
D. 200 joules
A
B
C
D
A.
4.
5.
20 joules
Four machines do the amounts of work listed in
the table shown. The time they take to do the
work is also listed. Which machine develops the
most power?
Machine
3.
6.
A
Work
Time
1,000 joules
10 sec
2,000 joules
10 sec
1,000 joules
2,000 joules
B.
B
7.
5 sec
5 sec
C.
C
8.
D. D
A garden tractor drags a plow with a force
of 500 newtons a distance of 10 meters in
20 seconds. How much work is done?
A.
25 joules
B.
C.
2,500 joules
D. 5,000 joules
9.
1,000 joules
As the length of time it takes a student to swim
100 meters decreases, the power developed by the
student
A.
decreases
C.
remains the same
B.
10.
increases
How much work is done on a 300-newton suitcase
to lift it 0.50 meter?
A.
600 joules
B.
C.
150 joules
D. 75 joules
11.
300 joules
A machine is able to do 30 joules of work in
6.0 seconds. The power developed by the machine
is
A.
0.20 watt
B.
C.
5.0 watts
D. 180 watts
What force is required to do 60 joules of work in
sliding an object a distance of 10 meters across a
level oor?
A.
6 newtons
B.
C.
60 newtons
D. 600 newtons
10 newtons
How much work will a 500-watt motor do in
10 seconds?
A.
0.02 joule
B.
C.
500 joules
D. 5,000 joules
50 joules
How much work is done when a rock weighing
10 newtons is lifted a vertical distance of
8 meters?
A.
18 joules
B.
C.
80 joules
D. 800 joules
2 joules
How long would it take a machine to do 5,000
joules of work if the power rating of the machine
is 100 watts?
A.
5,000 sec
B.
C.
10 sec
D. 0.2 sec
50 sec
The work done on a 10.0-kilogram mass to give it
a speed of 5.00 meters per second is
A.
page 1
0.50 watt
50.0 J
B.
2.00 J
C.
125 J
D. 2500 J
Work & Energy review sheet
12.
13.
16.
Car A and car B of equal mass travel up a hill.
Car A moves up the hill at a constant speed that
is twice the constant speed of car B. Compared
to the power developed by car B, the power
developed by car A is
A.
the same
B.
twice as much
C.
half as much
D. four times as much
5J
B.
C.
11 J
D. 50 J
A.
10 J
B.
60 J
C.
80 J
D. 100 J
In the diagram, 55 joules of work is needed to
raise a 10-newton 5.0 meters. How much work is
done to overcome friction as the weight is raised?
A.
A 20-newton block is at rest at the bottom of a
frictionless incline as shown in the diagram. How
much work must be done against gravity to move
the block to the top of the incline?
17.
5.5 J
Work is being done when a force
A.
acts vertically on a cart that can only move
horizontally
B.
is exerted by one team in a tug of war when
there is no movement
C.
is exerted while pulling a wagon up a hill
D. of gravitational attraction acts on a person
standing on the surface of the Earth
18.
14.
15.
One joule is equivalent to one
A.
newton
meter3
B.
kilogram meter3
C.
watt2 newton
D.
kilogram meter2
second2
Car A and car B are of equal mass and travel
up a hill. Car A moves up the hill at a constant
speed that is twice the constant speed of car B.
Compared to the power developed by car B, the
power developed by car A is
A.
the same
B.
C.
half as much
D. four times as much
The graph shows the force exerted on a block
as a function of the block's displacement in the
direction of the force. How much work did the
force do in displacing the block 5.0 meters?
A.
19.
twice as much
B.
20 J
C.
0.80 J
D. 4.0 J
A motor has an output of 1,000 watts. When
the motor is working at full capacity, how much
time will it require to lift a 50-newton weight
100 meters?
A.
page 2
0J
5s
B.
10 s
C.
50 s
D. 100 s
Work & Energy review sheet
20.
21.
A 6:0 102 -newton man climbing a rope at a
speed of 2.0 meters per second develops power at
the rate of
A.
1:2
101 W
B.
6:0
102 W
C.
3:0
102 W
D. 1:2
103 W
22.
As shown in the diagram, pulling a 9.8-newton
cart a distance of 0.50 meter along a plane
inclined at 15 requires 1.3 joules of work. If the
cart were raised 0.50 meter vertically instead of
being pulled along the inclined plane, the amount
of work would be
A.
less
B.
greater
C.
the same
A student performs a laboratory activity in which
a 15-newton force acts on a 2.0-kilogram mass.
The work done over time is summarized in the
table shown.
DATA TABLE
Time (s)
Work (J)
1.0
32
3.0
89
0
2.0
4.0
0
59
120
a) Using the information in the data table,
construct a graph on a grid, following the
directions given.
1) Develop an appropriate scale for
work and plot the points for a
work-versus-time graph.
2) Draw the best- t line.
b) Calculate the value of the slope of the graph
constructed in the previous part. (Show
all calculations, including equations and
substitutions with units.)
c) Based on your graph, how much time did it
take to do 75 joules of work?
page 3
Work & Energy review sheet
23.
26.
A student running up a ight of stairs increases
her speed at a constant rate. Which graph best
represents the relationship between work and time
for the student's run up the stairs?
A.
B.
C.
D.
The diagram pictured shows a worker moving
a 50.0-kilogram safe up a ramp by applying a
constant force of 300 newtons parallel to the ramp.
The data table shows the position of the safe as a
function of time.
Time
(s)
0.0
Distance Moved
up the Ramp
(m)
0.0
2.0
4.6
1.0
24.
A net force of 5.0 newtons moves a 2.0-kilogram
object a distance of 3.0 meters in 3.0 seconds.
How much work is done on the object?
A.
25.
1.0 J
B.
10 J
C.
15 J
3.0
4.0
5.0
2.2
6.6
8.6
11.0
D. 30 J
The diagram shows a 1:0 103 -newton crate to
be lifted at constant speed from the ground to
a loading dock 1.5 meters high in 5.0 seconds.
What power is required to lift the crate?
A.
1:5
103 W
B.
2:0
102 W
C.
3:0
102 W
D. 7:5
103 W
Using the information in the data table, construct
a line graph. Plot the data points and draw the
best- t line.
page 4
Work & Energy review sheet
27.
Using one or more complete sentences, explain the
physical signi cance of the slope of the graph.
28.
Calculate the work done by the worker in the rst
3.0 seconds. [Show all calculations, including the
equation and substitution with units.]
29.
How much work is done on a downhill skier by
an average braking force of 9:8 102 newtons to
stop her in a distance of 10 meters?
30.
A.
1:0
101 J
B.
9:8
101 J
C.
1:0
103 J
D. 9:8
103 J
31.
The accompanying diagram shows two identical
wooden planks, A and B, at di erent incline
angles, used to slide concrete blocks from a truck.
The accompanying graph represents the elongation
of a spring as a function of the applied force.
How much work must be done to stretch the
spring 0.40 meter?
A.
32.
Compared to the amount of work done against
friction by a block sliding down plank A, the
work done against friction by a block sliding down
plank B is
A.
less
B.
more
C.
the same
page 5
4.8 J
B.
6.0 J
C.
9.8 J
D. 24 J
Which combination of units can be used to express
work?
newton meter
second
A.
newton second
meter
B.
C.
newton/meter
D. newton meter
Work & Energy review sheet
33.
34.
In the accompanying diagram, 400. joules of work
is done raising a 72-newton weight a vertical
distance of 5.0 meters.
Base your answer(s) to the following question(s)
on the information and diagram below.
A 160.-newton box sits on a
10.-meter-long frictionless plane inclined at
an angle of 30. to the horizontal as shown.
Force (F) applied to a rope attached to the
box causes the box to move with a constant
speed up the incline.
Calculate the amount of work done in moving the
box from the bottom to the top of the inclined
plane. [Show all work, including the equation and
substitution with units.]
How much work is done to overcome friction as
the weight is raised?
A.
40. J
B.
360 J
C.
400. J
D. 760 J
page 6
Work & Energy review sheet
35.
36.
Base your answer(s) to the following question(s)
on the information below and on your knowledge
of physics.
Using a spring toy like the one
shown in the diagram, a physics teacher
pushes on the toy, compressing the
spring, causing the suction cup to stick
to the base of the toy.
A 3.0-kilogram block is initially at rest on a
frictionless, horizontal surface. The block is
moved 8.0 meters in 2.0 seconds by the application
of a 12-newton horizontal force, as shown in the
accompanying diagram.
What is the average power developed while
moving the block?
A.
When the teacher removes her
hand, the toy pops straight up and just
brushes against the ceiling. She does
this demonstration ve times, always
with the same result.
37.
24 W
B.
32 W
C.
48 W
D. 96 W
The diagram below shows points A, B, and C at or
near Earth's surface. As a mass is moved from A
to B, 100. joules of work are done against gravity.
When the teacher repeats the
demonstration for the sixth time the
toy crashes against the ceiling with
considerable force. The students notice
that in this trial, the spring and toy
separated from the base at the moment
the spring released.
The teacher puts the toy back
together, repeats the demonstration and
the toy once again just brushes against
the ceiling.
What is the amount of work done against gravity
as an identical mass is moved from A to C?
Describe the conversions that take place between
pairs of the three forms of mechanical energy,
beginning with the work done by the teacher on
the toy and ending with the form(s) of energy
possessed by the toy as it hits the ceiling.
[Neglect friction.]
A.
page 7
100. J
B.
173 J
C.
200. J
D. 273 J
Work & Energy review sheet
38.
40.
A box is pushed to the right with a varying
horizontal force. The graph below represents the
relationship between the applied force and the
distance the box moves.
Base your answer(s) to the following question(s)
on the information below.
A boy pushes his wagon at constant speed along
a level sidewalk. The graph below represents the
relationship between the horizontal force exerted
by the boy and the distance the wagon moves.
Force vs.Distance
What is the total work done in moving the box
6.0 meters?
A.
39.
9.0 J
B.
18 J
C.
27 J
D. 36 J
What is the total work done by the boy in pushing
the wagon 4.0 meters?
As shown in the diagram below, a child applies
a constant 20.-newton force along the handle
of a wagon which makes a 25 angle with the
horizontal.
A.
41.
How much work does the child do in moving the
wagon a horizontal distance of 4.0 meters?
A.
5.0 J
B.
34 J
C.
73 J
D. 80. J
page 8
5.0 J
B.
7.5 J
C.
120 J
D. 180 J
Which is an SI unit for work done on an object?
A.
kg m2
s2
B.
kg m2
s
C.
kg m
s2
D.
kg m
s
Work & Energy review sheet
42.
45.
The diagram here shows a 1-kilogram aluminum
sphere and a 3-kilogram copper sphere of equal
radius located 20 meters above the ground.
If the two spheres are allowed to fall freely to the
ground, they will experience the same
46.
A.
acceleration
B.
decrease in potential energy
C.
increase in kinetic energy
A 75-kilogram boy initially at rest skis down the
slope as shown. Assuming no frictional loss, what
will be his kinetic energy at the bottom of the
slope?
A.
1,500 joules
B.
C.
15,000 joules
D. 75,000 joules
The diagram shows a cart at four positions as it
moves along its track. At which positions is the
sum of the potential energy and kinetic energy of
the cart the same?
D. speci c gravity
43.
A pendulum swings as shown in the diagram.
At which position is the kinetic energy of the
pendulum bob least?
A.
A
B.
C.
C
D. D
B
A.
decreases
C.
remains the same
B.
A.
A and B, only
B.
B and C, only
C.
C and D, only
D. all positions, A through D
44. As a falling apple approaches the ground, its
potential energy
increases
page 9
7,500 joules
Work & Energy review sheet
47.
50.
The diagram here shows a 1-kilogram stone being
dropped from a bridge 100 meters above a gorge.
Each of the blocks in the diagrams is lifted
vertically for the distance indicated. Which block
will gain the most gravitational potential energy?
A.
B.
As the stone falls, the gravitational potential
energy of the stone
48.
A.
decreases
C.
remains the same
B.
increases
C.
As a pendulum moves from the bottom of its
swing to the top of its swing, the
A.
kinetic energy of the pendulum increases
B.
kinetic energy of the pendulum remains the
same
C.
potential energy of the pendulum decreases
D.
D. potential energy of the pendulum increases
49.
An object with a mass of 10.0 kilograms is
moving at a speed of 5.00 meters per second. The
kinetic energy of the mass is
A.
50.0 joules
B.
C.
125 joules
D. 250 joules
51.
2.00 joules
page 10
As a pendulum travels from the highest point of
its swing to the lowest point of its swing, its
potential energy
A.
decreases
C.
remains the same
B.
increases
Work & Energy review sheet
52.
53.
54.
The diagram shown here represents a block
suspended from a spring. The spring is stretched
0.200 meter. If the spring constant is 200 newtons
per meter, what is the weight of the block?
A.
40.0 N
B.
C.
8.00 N
D. 4.00 N
As the pendulum swings from position A to
position B as shown in the diagram, what is the
relationship of kinetic energy to potential energy?
[Neglect friction.]
20.0 N
A 0.10-meter spring is stretched from equilibrium
to position A and then to position B as shown in
the diagram. Compared to the spring's potential
energy at A, what is its potential energy at B ?
A.
The kinetic energy decrease is more than the
potential energy increase.
B.
The kinetic energy increase is more than the
potential energy decrease.
C.
The kinetic energy decrease is equal to the
potential energy increase.
D. The kinetic energy increase is equal to the
potential energy decrease.
55.
A.
the same
B.
twice as great
C.
half as great
D. four times as great
56.
Which graph best represents the relationship
between the kinetic energy (KE) of a moving
object as a function of its velocity (v)?
A.
B.
C.
D.
A basketball player who weighs 600 newtons
jumps 0.5 meter vertically o the oor. What is
her kinetic energy just before hitting the oor?
A.
page 11
30 J
B.
60 J
C.
300 J
D. 600 J
Work & Energy review sheet
57.
A.
58.
60.
When a 5-kilogram mass is lifted from the ground
to a height of 10 meters, the gravitational potential
energy of the mass is increased by approximately
0.5 J
B.
2J
C.
50 J
D. 500 J
Three people of equal mass climb a mountain
using paths A, B, and C shown in the diagram.
Along which path(s) does a person gain the
greatest amount of gravitational potential energy
from start to nish?
The graph represents the relationship between the
force applied to a spring and the elongation of the
spring. What is the spring constant?
A.
A, only
B.
B, only
C.
C, only
D. The gain is the same along all paths.
59.
A.
20 N/m
C.
0.80 N
B.
m
9.8 N/kg
61.
D. 0.050 m/N
An object 10 meters above the ground has Z joules
of potential energy. If the object falls freely, how
many joules of kinetic energy will it have gained
when it is 5 meters above the ground?
A.
Z
B.
2Z
C.
Z
2
D. 0
62.
Which graph best represents the relationship
between the elongation of an ideal spring and the
applied force?
A.
B.
C.
D.
A 20-kilogram object strikes the ground with
1,960 joules of kinetic energy after falling freely
from rest. How far above the ground was the
object when it was released?
A.
page 12
10 m
B.
14 m
C.
98 m
D. 200 m
Work & Energy review sheet
63.
65.
Which graph below shown represents the
relationship between the potential energy stored in
a spring (PE) and the change in the length of the
spring from its equilibrium position (X)?
A.
C.
The diagram shown represents a frictionless track.
A 10-kilogram block starts from rest at point A
and slides along the track.
B.
As the block moves from point A to point B,
the total amount of gravitational potential energy
changed to kinetic energy is approximately
D.
A.
Both potential energy and kinetic energy
increase.
B.
Both potential energy and kinetic energy
decrease.
C.
Potential energy increases and kinetic energy
decreases.
D. Potential energy decreases and kinetic energy
increases.
page 13
B.
20 J
C.
50 J
D. 500 J
66.
The diagram pictured shows a spring compressed
by a force of 6.0 newtons from its rest position
to its compressed position. Calculate the spring
constant for this spring. [Show all calculations,
including equations and substitutions with units.]
67.
An object with a speed of 20 meters per second
has a kinetic energy of 400 joules. The mass of
the object is
64. The diagram shows the path of a satellite in an
elliptical orbit around the Earth. As the satellite
moves from point A to point B, what changes
occur in its potential and kinetic energies?
A.
5J
A.
1.0 kg
B.
2.0 kg
C.
0.50 kg
D. 40 kg
Work & Energy review sheet
68.
69.
70.
Which variable expression is paired with a
corresponding unit?
A.
mass distance
time and watt
B.
mass distance2
time and watt
C.
mass distance2
time2 and joule
D.
mass distance
time3 and joule
The unstretched spring in the accompanying
diagram has a length of 0.40 meter and a spring
constant k. A weight is hung from the spring,
causing it to stretch to a length of 0.60 meter.
The diagram shows a 1.5-kilogram kitten jumping
from the top of a 1.80-meter-high refrigerator to a
0.90-meter-high counter.
Compared to the kitten's gravitational potential
energy on top of the refrigerator, the kitten's
gravitational potential energy on top of the counter
is
How many joules of elastic potential energy are
stored in this stretched spring?
71.
A.
half as great
B.
C.
one-fourth as great
D. four times as great
A.
0:020
C.
0:18
k
k
B.
0:080
D. 2:0
k
k
In the accompanying diagram, a student
compresses the spring in a pop-up toy 0.020 meter.
twice as great
If the spring has a spring constant of 340 newtons
per meter, how much energy is being stored in the
spring?
page 14
A.
0.068 J
B.
0.14 J
C.
3.4 J
D. 6.8 J
Work & Energy review sheet
72.
74.
Base your answer(s) to the following question(s)
on the information and diagram below, which is
drawn to a scale of 1.0 centimeter = 3.0 meters.
The accompanying diagram shows block A, having
mass 2m and speed v, and block B having mass
m and speed 2v.
A 650-kilogram roller coaster car starts from
rest at the top of the rst hill of its track
and glides freely. [Neglect friction.]
Compared to the kinetic energy of block A, the
kinetic energy of block B is
75.
Using one or more complete sentences, compare
the kinetic energy of the car at the top of the
second hill to its kinetic energy at the top of the
third hill.
73.
A.
the same
B.
C.
one-half as great
D. four times as great
Which graph best represents the elastic potential
energy stored in a spring (PEs ) as a function of
its elongation, x?
A.
Two vacationers walk out on a horizontal pier as
shown in the accompanying diagram.
B.
As they approach the end of the pier, their
gravitational potential energy will
A.
decrease
C.
remain the same
B.
C.
increase
D.
page 15
twice as great
Acces format version 4.4.158
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Work & Energy review sheet
02/20/2013
1.
Answer:
D
21.
Answer:
2.
Answer:
C
22.
Answer:
3.
Answer:
D
4.
Answer:
B
5.
Answer:
C
6.
Answer:
C
7.
Answer:
A
8.
Answer:
D
9.
Answer:
10.
Answer:
B
[see answer sheet]; slope = Wt = 30 J=s,
W
J
120 J
or xv = 120
4s or P = t = 4s = 30 W
2:5 s 0:3 s
23.
Answer:
B
24.
Answer:
C
25.
Answer:
C
26.
27.
Answer:
The slope is the average speed of the
safe
C
28.
Answer:
W=F
B
29.
Answer:
D
11.
Answer:
C
30.
Answer:
B
12.
Answer:
B
31.
Answer:
A
13.
Answer:
A
32.
Answer:
D
14.
Answer:
D
33.
Answer:
A
15.
Answer:
B
34.
Answer:
800 J
16.
Answer:
B
35.
Answer:
17.
Answer:
C
18.
Answer:
B
19.
Answer:
A
20.
Answer:
D
s; W = 1980 J
work into or potential energy(spring)
into or kinetic energy into or potential
energy (gravity)
36.
Answer:
C
37.
Answer:
A
38.
Answer:
C
Teacher's Key
Page 2
39.
Answer:
C
61.
Answer:
B
40.
Answer:
C
62.
Answer:
A
41.
Answer:
A
63.
Answer:
B
42.
Answer:
A
64.
Answer:
D
43.
Answer:
D
65.
Answer:
D
44.
Answer:
A
66.
Answer:
F = kx; 60 N = k (0:040); k = 150N=m;
45.
Answer:
C
46.
Answer:
67.
Answer:
B
D
47.
Answer:
68.
Answer:
C
A
48.
Answer:
69.
Answer:
A
D
49.
Answer:
70.
Answer:
A
C
50.
Answer:
71.
Answer:
A
B
51.
Answer:
72.
Answer:
The car's KE is less.
A
52.
Answer:
73.
Answer:
C
A
53.
Answer:
74.
Answer:
B
D
54.
Answer:
75.
Answer:
D
D
55.
Answer:
C
56.
Answer:
C
57.
Answer:
D
58.
Answer:
A
59.
Answer:
C
60.
Answer:
D