AP Physics 1
Scoring Guide
Assignment #13
1.
A 29.1-kg sledder is traveling along a level area with a speed of 8.96 m/s when she approaches a gentle
incline which makes an angle of 12.5 degrees with the horizontal. If the coefficient of friction between the
sled and the incline is 0.109, then what will be her speed at the bottom of the inclined plane, located 8.21 m
above the top of the incline
A
162.3 m/s
B
30.3 m/s
C
12.7 m/s
D
0 m/s
2.
A 50.0 kg crate is lifted to a height of 2.0 meters in the same time as a 25.0 kg crate is lifted to a height of 4
meters. The rate at which energy is used (i.e., power) in raising the 50.0 kg crate is ____ as the rate at which
energy is used to lift the 25.0 kg crate.
A
twice as much
B
half as much
C
the same
3.
A platform diver weighs 500 N. She steps off a diving board that is elevated to a height of 10 meters above
the water. The diver will possess ___ Joules of kinetic energy when she hits the water.
a. 10
b. 500
c. 510
d. 5000
e. more than 5000 .
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AP Physics 1
Scoring Guide
Assignment #13
A
10
B
500
C
510
D
5000
E
more than 5000
4.
A Watt is the standard metric unit of work. True or False
A
True
B
False
5.
A physical situation is described below. Simplify the work-energy equation by canceling any zero terms and
any energy terms (whether KE or PE) which are unchanging.
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AP Physics 1
Scoring Guide
Assignment #13
A
PE + W = KE
B
PE + W = PE
C
PE + W = O
D
PE = PE + KE
6.
What is the equation for kinetic energy?
A
1/2 m v(squared)
B
mgh
7.
A
block is pushed up an incline that makes a
angle with the horizontal, as shown in the figure.
Once the block is pushed a distance of
up the incline, the block remains at rest. What is the
approximate change in the gravitational potential energy of the block-Earth system when the block is held at
rest compared to its original location at the bottom of the incline?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
D
8.
An object of mass
is attached to a string of negligible mass and spun in a vertical circle of radius , as
shown in the figure above. As the object’s height increases, its speed decreases such that the object-Earth
system’s total mechanical energy remains constant. By how much does the object’s kinetic energy decrease
in moving from point , the lowest point on the circle, to point , the highest point on the circle?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
D
9.
A
B
C
An object is released from rest near and above Earth’s surface from a distance of
appropriate kinematic equation, a student predicts that it will take
for the object to reach the ground
with a speed of
. After performing the experiment, it is found that the object reaches the ground
after a time of
. How should the student determine the actual speed of the object when it reaches the
ground? Assume that the acceleration of the object is constant as it falls.
Use
but use the new time rather than
other quantities are known. Solve for
Use
Solve for
Use
since all
.
since all other quantities are known.
.
since the conservation of mechanical energy applies in this scenario, and the initial
height above the ground is known. Solve for
.
to determine the acceleration of the object as it falls since all other quantities
are known. Then use
quantities are known. Solve for
10.
and the vertical acceleration equal to
with the vertical acceleration equal to
Use
D
. After applying the
with
since all other
.
An object initially at rest falls from a height until it reaches the ground. Two of the following energy bar
charts represent the kinetic energy
and gravitational potential energy
of the object-Earth system at
two positions. The first position is when the object is initially released, and the second position is when the
object is halfway between its release point and the ground. Which two charts could represent the mechanical
energy of the object-Earth system? Select two answers.
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AP Physics 1
Scoring Guide
Assignment #13
A
B
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AP Physics 1
Scoring Guide
Assignment #13
C
D
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AP Physics 1
Scoring Guide
Assignment #13
11.
An experiment is conducted such that an applied force is exerted on a
object as it travels across a
horizontal surface in which frictional forces are NOT considered to be negligible. A graph of the net force
exerted on the object as a function of the object’s distance traveled is shown. How could a student use the
graph to determine the net work done on the object?
A
Multiply the average value of the applied force by the total distance the object traveled.
B
Multiply the slope of the best fit line by the total distance the object traveled.
C
Calculate the area bound by the line of best fit and the horizontal axis from
D
to
.
There is not enough information that is known or can be obtained from the graph to determine the net work
done on the object.
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AP Physics 1
Scoring Guide
Assignment #13
12.
The surface of an incline is coated with an experimental substance that is intended to reduce the frictional
force between a block and the surface of the incline. A
block is placed at the top of the incline at a
height of
, as shown in the figure. After the block is released from rest, the block slides down the
incline and a motion detector at the bottom of the incline measures the block’s speed as
after the
block is no longer on the incline. Which of the following claims is correct about the experimental
substance?
The experimental substance reduced all the frictional force because all the gravitational potential energy of
A
the Earth-block system at the top of the incline was converted into the kinetic energy of the block at the
bottom of the incline.
B
C
The experimental substance did not reduce all the frictional force because some of the gravitational potential
energy of the Earth-block system at the top of the incline was converted into nonmechanical energy.
The effectiveness of the experimental substance cannot be determined because the speed of the block at the
bottom of the inline, as measured by the motion detector, indicates that the block has more energy at this
location than the Earth-block system had at the top of the incline.
The effectiveness of the experimental substance cannot be determined without knowing the magnitude of the
D
frictional force between the block and the incline before and after the experimental substance was applied to
the incline.
A student is conducting an experiment to analyze the mechanical energy of a block-spring system. The student
places a block of mass
on a horizontal surface and attaches the block to a horizontal spring of negligible mass
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AP Physics 1
Scoring Guide
Assignment #13
and spring constant
, as shown in the figure. There is negligible friction between the block and the
horizontal surface. The other end of the spring is attached to a wall. The block-spring system is initially at the
spring’s equilibrium position.
13.
The student wants to collect data of the block-spring system that can be used to determine the work done on
the spring by the block when the spring is compressed. Which of the following includes only the measuring
devices that the student will need in order to collect the data?
A
Force probe and meterstick
B
Stopwatch and meterstick
C
Stopwatch and force probe
D
Force probe, stopwatch, and meterstick
14.
Based on data collected from the experiment, the student creates the graph that shows the force exerted on
the spring as a function of the distance the spring is compressed. How can the student use the data to
experimentally determine the work done on the spring by the block?
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AP Physics 1
Scoring Guide
Assignment #13
A
Determine the slope of the line of best fit through the data from
B
Determine the area bound by the line of best fit through the data and the horizontal axis from
.
C
Use the maximum value of the force exerted on the spring and multiply that value by the maximum distance
that the spring is compressed.
D
to
.
to
This graph cannot be used to determine the work done by the block on the spring because the force exerted
on the spring by the block is not constant.
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AP Physics 1
Scoring Guide
Assignment #13
15.
A student conducts an experiment in which an object is released from rest and falls to the floor. In the
experiment, frictional forces CANNOT be neglected. The student uses experimental data to create two
graphs. Figure 1 is a graph of kinetic energy of the object as a function of time. Figure 2 is a graph of the
object-Earth system’s gravitational potential energy as a function of time. How should the student use one or
both graphs to determine how much the total mechanical energy changes after
?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
Calculate the magnitude of the difference between the final kinetic energy of the object and the final kinetic
energy of the object by using the graph in Figure 1.
Calculate the magnitude of the difference between the final gravitational potential energy of the system and
the initial gravitational potential energy of the system by using the graph in Figure 2.
Calculate the magnitude of the difference between the final kinetic energy of the object found from the graph
in Figure 1 and the final gravitational potential energy of the object-Earth system found from the graph in
Figure 2.
Calculate the magnitude of the difference between the final kinetic energy of the object found from the graph
D
in Figure 1 and the initial gravitational potential energy of the object-Earth system found from the graph in
Figure 2.
A conveyor belt ramp of length
is inclined at
with respect to the horizontal and is used to move objects
from one location to another location. When an object is placed on the conveyor belt, the object travels up the
incline with a constant speed of
. A motor is used to keep the conveyor belt moving. The mass of the objects
that are placed on the conveyor belt are varied.
16.
Suppose the motor breaks and a person must push an object of mass
from the bottom of the incline to
the top of the incline. The person can exert a force of
on the object parallel to the incline. What is the
approximate amount of work that the person does on the object to move it to the top of the incline? Assume
that all frictional forces are negligible.
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
D
17.
A
B
C
D
18.
For the system that only includes the object, which of the following claims best describes what happens to
the mechanical energy of the system while the object is moving from the bottom of the ramp to the top of
the ramp?
The mechanical energy of the object increases because the gravitational potential energy increases as the
object moves up the ramp.
The mechanical energy of the object decreases because the force due to gravity from Earth does negative
work on the object as it moves up the ramp.
The mechanical energy of the object is constant because the kinetic energy of the object is constant.
A determination of the change of the mechanical energy of the object cannot be made without knowing the
power of the motor that is used to move the conveyor belt.
Object and object are placed on the incline such that the motor moves the conveyor belt. The mass of
object is greater than the mass of object . After both objects have been placed on the conveyor belt and
travel at a constant speed, how does the rate of change of the gravitational potential energy of the object
–Earth system per unit of time
compare to that for the object
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–Earth system
?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
, because the speed of the conveyor belt remains constant and both objects move at
the same constant speed.
, because the speed of the conveyor belt remains constant and both objects move at a
constant speed.
C
, because object
has a greater mass than object
.
D
, because object
has a greater mass than object
.
19.
Two blocks of the same mass but made of different material slide across a horizontal, rough surface and
eventually come to rest. A graph of the kinetic energy of each block as a function of position along the
surface is shown. Which of the following is a true statement about the frictional force
that is exerted on
the two blocks?
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AP Physics 1
Scoring Guide
Assignment #13
A
, since the force of friction is represented as the slope for each of the two curves.
B
, since the force of friction is represented as the inverse slope for each of the two curves.
C
D
, since the force of friction is represented as the inverse of the area bound by each curve and the
horizontal axis.
, since the force of friction is represented as the area bound by each curve and the horizontal
axis.
A student conducts an experiment in which an object is released from rest above a motion detector so that data can
be collected about the object’s motion as the object falls to the ground. The experiment is conducted near Earth’s
surface. All frictional forces are considered to be negligible unless otherwise stated.
20.
The student collects the data necessary to graph the object’s kinetic energy as a function of time, as shown.
Which of the following graphs represents the sum of the kinetic energy and gravitational potential energy
of the object-Earth system as a function of time?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
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AP Physics 1
Scoring Guide
Assignment #13
C
D
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AP Physics 1
Scoring Guide
Assignment #13
21.
The student wants to collect data to determine the work done by the force due to gravity on the object as it
falls. Which of the following lists contains the fewest number of measuring devices, in addition to the
motion detector, that the student can use?
A
Spring scale
B
Spring scale and meterstick
C
Stopwatch and meterstick
D
Spring scale, meterstick, and stopwatch
22.
A graph of the net force exerted on an object as a function of position is shown for the object of mass
as it travels a horizontal distance
. Which expression represents the change in the kinetic energy of
the object?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
D
23.
A
object is released from rest near and above Earth’s surface such that the object-Earth system’s
gravitational potential energy as a function of time is shown in the graph. Which of the following graphs
represents the kinetic energy of the object as a function of time? Assume all frictional forces are considered
to be negligible.
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
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AP Physics 1
Scoring Guide
Assignment #13
D
24.
A person starting from rest at point swings along a circular arc from a rope, as shown above. Point is at a
lower height than point . What is the trajectory of the person when the person lets go of the rope at Point
?
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AP Physics 1
Scoring Guide
Assignment #13
A
B
C
D
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AP Physics 1
Scoring Guide
Assignment #13
25.
The small block shown in the figure above was released from rest at point
that friction was considered to be negligible. The block reached point
and , what kind of work did the track do on the block, and why?
A
B
C
D
and slid down the track such
with speed
. Between points
Positive work, because the block’s kinetic energy increased.
Positive work, because a component of the gravitational force is directed along the track, making the block
gain kinetic energy.
Zero work, because the average force exerted by the track on the block is zero.
Zero work, because the track does not exert a force on the block directed along the block’s direction of
motion.
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AP Physics 1
Scoring Guide
Assignment #13
26.
A planet orbits a star along an elliptical path, as shown in the figure above. How do the planet’s kinetic
energy and the total mechanical energy of the star-planet system change as the planet moves from point X to
point Y?
A
B
C
D
Planet’s Kinetic Energy
System’s Total Mechanical Energy
Increases
Remains the same
Planet’s Kinetic Energy
System’s Total Mechanical Energy
Increases
Increases
Planet’s Kinetic Energy
System’s Total Mechanical Energy
Decreases
Remains the same
Planet’s Kinetic Energy
System’s Total Mechanical Energy
Decreases
Decreases
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AP Physics 1
Scoring Guide
Assignment #13
27.
Blocks and are connected by a string that passes over a pulley, as shown in the figure. Block has
more mass than Block . The string and pulley have negligible mass, and the pulley rotates with negligible
friction. After the blocks are released from rest, what happens to the mechanical energy
of the system
consisting of the two blocks and Earth?
A
decreases.
B
remains constant.
C
increases.
D
The change of
cannot be determined without knowing the ratio of the blocks’ masses and their initial
distances from Earth’s surface.
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AP Physics 1
Scoring Guide
Assignment #13
28.
Figure 1 shows the kinetic energy as a function of time for a
object that is released from rest and falls
toward Earth’s surface. Figure 2 shows the kinetic energy as a function of time for a
object that is
released from rest and falls toward Earth’s surface. Both objects are released simultaneously from the same
height. How much does the gravitational potential energy of the object-object-Earth system change from
to
?
A
B
C
D
29.
A student wants to approximate the amount of work that the force due to gravity does on the student as the
student walks up a set of stairs. Which of the following measurements must the student collect in order to
approximate the amount of work done by Earth on the student? Select two answers.
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AP Physics 1
Scoring Guide
Assignment #13
A
The mass of the student.
B
The angle between the inclined portion of the stairs and the horizontal.
C
The total inclined length of the stairs.
D
The final vertical height above the initial vertical position.
30.
An experiment is conducted such that an applied force is exerted on a
object as it travels across a
horizontal surface. A graph of the net force exerted on the object as a function of the object’s distance
traveled is shown. How could a student use the graph to determine the work done by the applied force?
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AP Physics 1
Scoring Guide
Assignment #13
A
Multiply the maximum value of the applied force by the total distance the object traveled.
B
Multiply the weight of the object by the total distance traveled by the object.
C
Calculate the slope of the line of best fit.
D
Calculate the area bound by the line of best fit and the horizontal axis from
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to
.
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