Physics Midterm Review
Name:
1.
Date:
Which quantities are scalar?
A.
speed and work
B.
velocity and force
C.
distance and acceleration
4.
A.
D. momentum and power
2.
5.
A 160.-kilogram space vehicle is traveling along a
straight line at a constant speed of 800. meters per
second. The magnitude of the net force on the
space vehicle is
A.
0N
C.
8:00
1:60
102 N
D. 1:28
105 N
B.
102 N
6.
3.
A vertical spring has a spring constant of
100. newtons per meter. When an object is
attached to the bottom of the spring, the spring
changes from its unstretched length of 0.50 meter
to a length of 0.65 meter. The magnitude of the
weight of the attached object is
A student throws a 5.0-newton ball straight up.
What is the net force on the ball at its maximum
height?
A.
0.0 N
B.
5.0 N, up
C.
5.0 N, down
D. 9.8 N, down
page 1
1.1 N
B.
15 N
C.
50. N
D. 65 N
A 1.5-kilogram cart initially moves at 2.0 meters
per second. It is brought to rest by a constant net
force in 0.30 second. What is the magnitude of
the net force?
A.
0.40 N
B.
0.90 N
C.
10. N
D. 15 N
As a 5:0 102 –newton basketball player jumps
from the oor up toward the basket, the magnitude
of the force of her feet on the oor is 1:0 103
newtons. As she jumps, the magnitude of the
force of the oor on her feet is
A.
5:0
102 N
B.
1:0
103 N
C.
1:5
103 N
D. 5:0
105 N
7.
A 0.0600-kilogram ball traveling at 60.0 meters
per second hits a concrete wall. What speed must
a 0.0100-kilogram bullet have in order to hit the
wall with the same magnitude of momentum as
the ball?
10.
A block slides across a rough, horizontal tabletop.
As the block comes to rest, there is an increase in
the block-tabletop system's
A.
gravitational potential energy
A.
3.60 m/s
B.
6.00 m/s
B.
elastic potential energy
C.
360. m/s
D. 600. m/s
C.
kinetic energy
D. internal (thermal) energy
8.
The Hubble telescope's orbit is 5:6 105 meters
above Earth's surface. The telescope has a mass
of 1:1 104 kilograms. Earth exerts a gravitational
force of 9:1 104 newtons on the telescope. The
magnitude of Earth's gravitational eld strength at
this location is
A.
1:5
10
C.
8.3 N/kg
20 N/kg
B.
11.
0.12 N/kg
D. 9.8 N/kg
Which diagram best represents the position of a
ball, at equal time intervals, as it falls freely from
rest near Earth's surface?
A.
9.
B.
C.
D.
Which energy transformation occurs in an
operating electric motor?
A.
electrical ! mechanical
B.
mechanical ! electrical
C.
chemical ! electrical
D. electrical ! chemical
page 2
Physics Midterm Review
12.
A di erent force is applied to each of four di erent
blocks on a frictionless, horizontal surface. In
which diagram does the block have the greatest
inertia 2.0 seconds after starting from rest?
14.
Without air resistance, a kicked ball would reach a
maximum height of 6.7 meters and land 38 meters
away. With air resistance, the ball would travel
A.
6.7 m vertically and more than 38 m
horizontally
B.
38 m horizontally and less than 6.7 m
vertically
B.
C.
more than 6.7 m vertically and less than 38 m
horizontally
C.
D. less than 38 m horizontally and less than
6.7 m vertically
A.
D.
15.
13.
A car is moving with a constant speed of
20. meters per second. What total distance does
the car travel in 2.0 minutes?
A.
10. m
B.
40. m
C.
1200 m
D. 2400 m
The diameter of an automobile tire is closest to
2m
A.
10
C.
101 m
B.
100 m
16.
D. 102 m
page 3
A car, initially traveling at 15 meters per second
north, accelerates to 25 meters per second north
in 4.0 seconds. The magnitude of the average
acceleration is
A.
2.5 m/s2
B.
6.3 m/s2
C.
10. m/s2
D. 20. m/s2
Physics Midterm Review
17.
An object is in equilibrium. Which force vector
diagram could represent the force(s) acting on the
object?
A.
B.
C.
D.
18.
Which graph best represents the relationship
between the potential energy stored in a spring
and the change in the spring's length from its
equilibrium position?
A.
B.
C.
D.
19.
An electric motor has a rating of 4:0 102 watts.
How much time will it take for this motor to
lift a 50.-kilogram mass a vertical distance of
8.0 meters? [Assume 100% e ciency.]
A.
page 4
0.98 s
B.
9.8 s
C.
98 s
D. 980 s
Physics Midterm Review
20.
A compressed spring in a toy is used to launch a
5.00-gram ball. If the ball leaves the toy with an
initial horizontal speed of 5.00 meters per second,
the minimum amount of potential energy stored in
the compressed spring was
A.
0.0125 J
B.
C.
0.0625 J
D. 0.125 J
21.
0.0250 J
22.
page 5
Which combination of fundamental units can be
used to express the amount of work done on an
object?
kg m=s2
A.
kg m=s
B.
C.
kg m2 =s2
D. kg m2 =s3
Calculate the minimum power output of an electric
motor that lifts a 1:30 104 -newton elevator
car vertically upward at a constant speed of
1.50 meters per second. [Show all work, including
the equation and substitution with units.]
Physics Midterm Review
23.
Base your answer(s) to the following question(s) on the information and diagram below and on your knowledge of
physics.
A 1:5 103 -kilogram car is driven at a constant speed of 12 meters per second counterclockwise around
a horizontal circular track having a radius of 50. meters, as represented below.
Track, as Viewed from Above
On the diagram provided, draw an arrow to indicate the direction of the velocity of the car when it is at the
position shown. Start the arrow on the car.
24.
Calculate the magnitude of the centripetal acceleration of the car. [Show all work, including the equation and
substitution with units.]
page 6
Physics Midterm Review
25.
Base your answer(s) to the following question(s)
on the information below and on your knowledge
of physics.
A football is thrown at an angle of
30. above the horizontal. The magnitude
of the horizontal component of the ball's
initial velocity is 13.0 meters per second.
The magnitude of the vertical component of
the ball's initial velocity is 7.5 meters per
second. [Neglect friction.]
On the axes provided, draw a graph representing
the relationship between the horizontal
displacement of the football and the time the
football is in the air.
26.
27.
Calculate the magnitude of the force of friction
acting on the moving block. [Show all work,
including the equation and substitution with units.]
28.
Determine the magnitude of the net force acting
on the moving block.
29.
Describe what happens to the magnitude of the
velocity of the block as the block slides across the
table.
30.
Two 20.-newton forces act concurrently on an
object. What angle between these forces will
produce a resultant force with the greatest
magnitude?
Base your answer(s) to the following question(s)
on the information below and on your knowledge
of physics.
A.
0
B.
45
C.
90.
D. 180.
The diagram below represents a
4.0-newton force applied to a 0.200-kilogram
copper block sliding to the right on a
horizontal steel table.
31.
Determine the weight of the block.
page 7
In a race, a runner traveled 12 meters in
4.0 seconds as she accelerated uniformly from rest.
The magnitude of the acceleration of the runner
was
A.
0.25 m/s2
B.
1.5 m/s2
C.
3.0 m/s2
D. 48 m/s2
Physics Midterm Review
32.
A projectile is launched at an angle above
the ground. The horizontal component of the
projectile's velocity, vx , is initially 40. meters per
second. The vertical component of the projectile's
velocity, vy , is initially 30. meters per second.
What are the components of the projectile's
velocity after 2.0 seconds of ight? [Neglect
friction.]
A.
vx = 40: m=s and vy = 10: m=s
B.
vx = 40: m=s and vy = 30: m=s
C.
vx = 20: m=s and vy = 10: m=s
35.
A.
D. vx = 20: m=s and vy = 30: m=s
33.
36.
A ball is thrown with an initial speed of 10. meters
per second. At what angle above the horizontal
should the ball be thrown to reach the greatest
height?
A.
0
B.
30.
C.
45
2.4 N
B.
3.4 N
C.
8.0 N
D. 27 N
Which situation represents a person in equilibrium?
A.
a child gaining speed while sliding down a
slide
B.
a woman accelerating upward in an elevator
C.
a man standing still on a bathroom scale
D. a teenager driving around a corner in his car
D. 90.
37.
34.
An 8.0-newton wooden block slides across a
horizontal wooden oor at constant velocity. What
is the magnitude of the force of kinetic friction
between the block and the oor?
A rock is thrown straight up into the air. At the
highest point of the rock's path, the magnitude of
the net force acting on the rock is
Which object has the greatest inertia?
A.
less than the magnitude of the rock's weight,
but greater than zero
A.
a 0.010-kg bullet traveling at 90. m/s
B.
B.
a 30.-kg child traveling at 10. m/s on her bike
greater than the magnitude of the rock's
weight
C.
a 490-kg elephant walking with a speed of
1.0 m/s
C.
the same as the magnitude of the rock's
weight
D. zero
D. a 1500-kg car at rest in a parking lot
page 8
Physics Midterm Review
38.
The diagram below shows a compressed spring
between two carts initially at rest on a horizontal,
frictionless surface. Cart A has a mass of
2 kilograms and cart B has a mass of 1 kilogram.
A string holds the carts together.
40.
The string is cut and the carts move apart.
Compared to the magnitude of the force the spring
exerts on cart A, the magnitude of the force the
spring exerts on cart B is
A.
the same
B.
C.
twice as great
D. four times as great
41.
half as great
At a certain location, a gravitational force
with a magnitude of 350 newtons acts on a
70.-kilogram astronaut. What is the magnitude of
the gravitational eld strength at this location?
A.
0.20 kg/N
B.
5.0 N/kg
C.
9.8 m/s2
D. 25 000 N kg
In the diagram below, an ideal pendulum released
from position A swings freely to position B.
As the pendulum swings from A to B, its total
mechanical energy
39.
An 8.0-newton block is accelerating down a
frictionless ramp inclined at 15 to the horizontal,
as shown in the diagram below.
A.
decreases, then increases
B.
increases, only
C.
increases, then decreases
D. remains the same
What is the magnitude of the net force causing
the block's acceleration?
A.
0N
B.
2.1 N
C.
7.7 N
42.
D. 8.0 N
page 9
The approximate length of an unsharpened No. 2
pencil is
2m
A.
2:0
10
C.
2:0
100 m
B.
2:0
D. 2:0
10
1m
101 m
Physics Midterm Review
43.
The diagram below shows an 8.0-kilogram cart
moving to the right at 4.0 meters per second about
to make a head-on collision with a 4.0-kilogram
cart moving to the left at 6.0 meters per second.
45.
If a motor lifts a 400.-kilogram mass a vertical
distance of 10. meters in 8.0 seconds, the minimum
power generated by the motor is
A.
3:2
102 W
B.
5:0
102 W
C.
4:9
103 W
D. 3:2
104 W
After the collision, the 4.0-kilogram cart moves
to the right at 3.0 meters per second. What is
the velocity of the 8.0-kilogram cart after the
collision?
A.
0.50 m/s left
B.
0.50 m/s right
C.
5.5 m/s left
D. 5.5 m/s right
44. Four forces act concurrently on a block on a
horizontal surface as shown in the diagram below.
46.
A 4.0-kilogram object is accelerated at 3.0 meters
per second2 north by an unbalanced force. The
same unbalanced force acting on a 2.0-kilogram
object will accelerate this object toward the north
at
A.
12 m/s2
B.
6.0 m/s2
C.
3.0 m/s2
D. 1.5 m/s2
As a result of these forces, the block
A.
moves at constant speed to the right
B.
moves at constant speed to the left
C.
accelerates to the right
D. accelerates to the left
page 10
Physics Midterm Review
47.
Which graph represents the relationship between
the kinetic energy and the speed of a freely falling
object?
48.
A.
Which graph represents the relationship between
the magnitude of the gravitational force, Fg ,
between two masses and the distance, r, between
the centers of the masses?
A.
B.
B.
C.
C.
D.
D.
page 11
Physics Midterm Review
49.
Base your answer(s) to the following question(s)
on the information on the graph below.
51.
The graph shows the relationship
between speed and elapsed time for a car
moving in a straight line.
Base your answer(s) to the following question(s)
on the information below.
A 28-gram rubber stopper is attached
to a string and whirled clockwise in a
horizontal circle with a radius of 0.80 meter.
The diagram in your answer booklet
represents the motion of the rubber stopper.
The stopper maintains a constant speed of
2.5 meters per second.
Calculate the magnitude of the centripetal
acceleration of the stopper.
52.
On the diagram below, draw an arrow showing the
direction of the centripetal force acting on the
stopper when it is at the position shown.
Determine the magnitude of the acceleration of the
car.
50.
Calculate the total distance the car traveled during
the time interval 4.0 seconds to 8.0 seconds.
page 12
Physics Midterm Review
53.
Base your answer(s) to the following question(s)
on the information and diagram below.
55.
Calculate the total increase in the gravitational
potential energy of the crate after it has slid
6.00 meters along the incline.
56.
State what happens to the kinetic energy of the
crate as it slides along the incline.
57.
State what happens to the internal energy of the
crate as it slides along the incline.
58.
A 100-kilogram person acquires a velocity of
15 meters per second down a ski slope. What is
the skier's kinetic energy?
A 30.4-newton force is used to slide a
40.0-newton crate a distance of 6.00 meters
at constant speed along an incline to a
vertical height of 3.00 meters.
Determine the total work done by the 30.4-newton
force in sliding the crate along the incline.
54.
Base your answer(s) to the following question(s)
on the information and diagram below.
A 30.4-newton force is used to slide a
40.0-newton crate a distance of 6.00 meters
at constant speed along an incline to a
vertical height of 3.00 meters.
59.
Determine the total work done by the 30.4-newton
force in sliding the crate along the incline.
page 13
A.
22,500 joules
B.
11,250 joules
C.
1,500 joules
D. 115 joules
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
Physics Midterm Review
60.
61.
62.
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
63.
decreases
C.
remains the same
B.
A.
work
B.
momentum
C.
potential energy
D. force
7,500 joules
64. 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?
As a falling apple approaches the ground, its
potential energy
A.
A “push or pull” best describes the term
increases
A cart weighing 10 newtons is pushed 10 meters
on a level surface by a force of 5 newtons. What
is the increase in its potential energy?
A.
1 joule
B.
C.
100 joules
D. 0 joules
A.
A and B, only
B.
B and C, only
C.
C and D, only
D. all positions, A through D
50 joules
page 14
Physics Midterm Review
65.
The diagram here shows a 1-kilogram stone being
dropped from a bridge 100 meters above a gorge.
66.
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
A.
decreases
C.
remains the same
B.
increases
C.
D.
67.
page 15
One joule is equivalent to one
A.
newton
meter3
B.
kilogram-meter3
C.
watt2 -newton
D.
kilogram-meter3
second2
Physics Midterm Review
68.
69.
As the pendulum swings freely from A to B as
shown, the gravitational potential energy of the
ball
A.
decreases
B.
increases
C.
remains the same
71.
The diagram shown represents two objects at rest
on a frictionless horizontal surface with a spring
compressed between them. When the compressed
spring is released, the two objects are pushed
apart.
What kinetic energy does the 2.0-kilogram object
have after gaining a velocity of 5.0 meters per
second?
A.
70.
25 J
B.
20 J
C.
10 J
72.
D. 5.0 J
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 same
B.
twice as great
C.
half as great
D. four times as great
The sum of the kinetic and potential energies of
an object's molecules is called the object's
A.
temperature
B.
heat of fusion
C.
internal energy
D. speci c heat
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
73.
20.0 N
page 16
What is the spring constant of a spring of
negligible mass which gained 8 joules of potential
energy as a result of being compressed 0.4 meter?
A.
100 N/m
B.
50 N/m
C.
0.3 N/m
D. 40 N/m
Physics Midterm Review
74.
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.]
76.
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.
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.
Z
B.
2Z
C.
Z
2
D. 0
D. The kinetic energy increase is equal to the
potential energy decrease.
77.
75.
The graph represents the relationship between the
force applied to a spring and the elongation of the
spring. What is the spring constant?
Which quantity and unit are correctly paired?
A.
velocity: m/s2
B.
momentum:
C.
energy:
kg m
s2
kg m2
s2
D. work: kg/m
A.
20 N/m
C.
0.80 N
B.
m
9.8 N/kg
D. 0.050 m/N
page 17
Physics Midterm Review
78.
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?
A.
A, only
B.
B, only
C.
C, only
80.
A box weighing 1:0 102 newtons is dragged to
the top of an incline, as shown in the diagram.
The gravitational potential energy of the box at the
top of the incline is approximately
A.
1:0
102 J
B.
6:0
102 J
C.
8:0
102 J
D. 1:0
103 J
D. The gain is the same along all paths.
81.
79.
A 20-newton weight is attached to a spring,
causing it to stretch, as shown in the diagram.
What is the spring constant of this spring?
The graph shows the elongation of a spring as a
function of the force. What is the value of the
spring constant?
A.
0.1 m/N
B.
0.1 N/m
C.
10 m/N
D. 10 N/m
page 18
A.
0.050 N/m
B.
0.25 N/m
C.
20 N/m
D. 40 N/m
Physics Midterm Review
82.
The accompanying diagram shows block A, having
mass 2m and speed v, and block B having mass
m and speed 2v.
84.
A spring has a spring constant of 120 newtons per
meter. How much potential energy is stored in the
spring as it is stretched 0.20 meter?
A.
2.4 J
B.
4.8 J
C.
12 J
D. 24 J
Compared to the kinetic energy of block A, the
kinetic energy of block B is
83.
A.
the same
B.
twice as great
C.
one-half as great
D. four times as great
Base your answer(s) to the following question(s)
on the graph and information below.
The graph below represents a cooling
curve for 10. kilograms of a substance as it
cools from a vapor at 160. C to a solid at
20. C. Energy is removed from the sample
at a constant rate.
85.
The accompanying diagram shows a moving,
5.00-kilogram cart at the foot of a hill 10.0 meters
high. For the cart to reach the top of the hill,
what is the minimum kinetic energy of the cart in
the position shown? [Neglect energy loss due to
friction.]
A.
4.91 J
B.
50.0 J
C.
250. J
D. 491 J
While the substance is cooling during the liquid
phase, the average kinetic energy of the molecules
of the substance
A.
decreases
C.
remains the same
B.
increases
page 19
Physics Midterm Review
86.
Which graph best represents the elastic potential
energy stored in a spring (PEs ) as a function of
its elongation, x?
87.
Base your answer(s) to the following question(s)
on the information and table below.
The table lists the kinetic energy of a
4.0-kilogram mass as it travels in a straight
line for 12.0 seconds.
A.
Time
Kinetic Energy
(seconds)
(joules)
0.0
2.0
4.0
6.0
10.0
12.0
B.
0.0
8.0
18
32
32
32
Mark an appropriate scale on the axis labeled
“Kinetic Energy (J).”
C.
D.
page 20
Physics Midterm Review
88.
Plot the data points for kinetic energy versus time.
90.
Base your answer(s) to the following question(s)
on the information and diagram below.
A mass, M, is hung from a spring and
reaches equilibrium at position B. The mass
is then raised to position A and released.
The mass oscillates between positions A and
C. [Neglect friction.]
At which position, A, B, or C, is mass M located
when the kinetic energy of the system is at a
maximum? Explain your choice.
89.
What is the total electrical energy used by a
1500-watt hair dryer operating for 6.0 minutes?
A.
4.2 J
C.
9:0
B.
103 J
91.
At which position, A, B, or C, is mass M located
when the gravitational potential energy of the
system is at a maximum? Explain your choice.
92.
At which position, A, B, or C, is mass M located
when the elastic potential energy of the system is
at a maximum? Explain your choice.
250 J
D. 5:4
105 J
page 21
Physics Midterm Review
93.
If the speed of a car is doubled, the kinetic energy
of the car is
A.
quadrupled
B.
C.
quartered
D. halved
95.
Base your answer(s) to the following question(s)
on the information and diagram below.
A 1000.-kilogram empty cart moving with a speed
of 6.0 meters per second is about to collide with
a stationary loaded cart having a total mass of
5000. kilograms, as shown. After the collision,
the carts lock and move together. [Assume friction
is negligible.]
doubled
How does the kinetic energy of the combined carts
after the collision compare to the kinetic energy of
the carts before the collision?
94.
The diagram below shows a 0.1-kilogram apple
attached to a branch of a tree 2 meters above a
spring on the ground below.
96.
A 250.-kilogram car is initially at rest at
point A on a roller coaster track. The car
carries a 75-kilogram passenger and is
20. meters above the ground at point A.
[Neglect friction.]
The apple falls and hits the spring, compressing
it 0.1 meter from its rest position. If all of the
gravitational potential energy of the apple on
the tree is transferred to the spring when it is
compressed, what is the spring constant of this
spring?
A.
10 N/m
B.
C.
100 N/m
D. 400 N/m
Base your answer(s) to the following question(s)
on the information and diagram below.
40 N/m
Compare the total mechanical energy of the car
and passenger at points A, B, and C.
page 22
Physics Midterm Review
97.
Base your answer(s) to the following question(s)
on the information and diagram below.
98.
A 3.0-kilogram object is placed on a
frictionless track at point A and released
from rest. (Assume the gravitational potential
energy of the system to be zero at point C).
A wooden crate is pushed at constant speed across
a level wooden oor. Which graph best represents
the relationship between the total mechanical
energy of the crate and the duration of time the
crate is pushed?
A.
Calculate the kinetic energy of the object at
point B. [Show all work, including the equation
and substitution with units.]
B.
C.
D.
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Physics Midterm Review
99.
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
103. In the diagram, 55 joules of work is needed to
raise a 10-newton weight 5.0 meters at a constant
speed. How much work is done to overcome
friction as the weight is raised?
20 joules
A.
5J
B.
5.5 J
C.
11 J
D. 50 J
100. How much work is done on a 300-newton suitcase
to lift it 0.50 meter?
A.
600 joules
B.
300 joules
C.
150 joules
D. 75 joules
104. 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?
101. 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
A.
0.50 watt
0.02 joule
B.
C.
500 joules
D. 5,000 joules
B.
20 J
C.
0.80 J
D. 4.0 J
105. 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
102. How much work will a 500-watt motor do in
10 seconds?
A.
0J
50 joules
page 24
A.
less
B.
greater
C.
the same
Physics Midterm Review
106. A 45-kilogram bicyclist climbs a hill at a constant
speed of 2.5 meters per second by applying an
average force of 85 newtons. Approximately how
much power does the bicyclist develop?
A.
110 W
B.
C.
1100 W
D. 1400 W
109. 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.
210 W
107. The accompanying diagram shows two identical
wooden planks, A and B, at di erent incline
angles, used to slide concrete blocks from a truck.
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.]
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
108. A 10.-newton force is required to move a
3.0-kilogram box at constant speed. How much
power is required to move the box 8.0 meters in
2.0 seconds?
A.
40. W
B.
20. W
C.
15 W
D. 12 W
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Physics Midterm Review
110. Base your answer(s) to the following question(s)
on the information below and on your knowledge
of physics.
112. 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.
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.
What is the average power developed while moving
the block?
A.
24 W
B.
32 W
C.
48 W
D. 96 W
J s
D. J=s
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.
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.
113. One watt is equivalent to one
A.
N m
B.
N=m
C.
The teacher puts the toy back
together, repeats the demonstration and
the toy once again just brushes against
the ceiling.
114. 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.
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.]
How much work does the child do in moving the
wagon a horizontal distance of 4.0 meters?
111. Explain, in terms of mass and energy, why the
spring toy hits the ceiling in the sixth trial and
not in the other trials.
A.
page 26
5.0 J
B.
34 J
C.
73 J
D. 80. J
Physics Midterm Review
115. Student A lifts a 50.-newton box from the oor to
a height of 0.40 meter in 2.0 seconds. Student B
lifts a 40.-newton box from the oor to a height of
0.50 meter in 1.0 second. Compared to student A,
student B does
A.
the same work but develops more power
B.
the same work but develops less power
C.
more work but develops less power
D. less work but develops more power
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Physics Midterm Review