AP Physics C: Mechanics
Test Booklet
In-Class Review 5
Name
1.
Three objects of mass ,
, and
are at positions
above. The center of mass is located at position
,
, and
, respectively, as shown
A
B
C
D
E
A large truck of mass
is traveling at a speed of
The truck and car stick together after the collision.
when it collides with a small car of mass
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that is at rest.
Page 1 of 15
AP Physics C: Mechanics
Test Booklet
In-Class Review 5
2. The speed of the center of mass of the truck-car system as the truck and car move off together is
A
B
C
D
E
3.
An object having an initial momentum that may be represented by the vector above strikes an object that is
initially at rest. Which of the following sets of vectors may represent the momenta of the two objects after
the collision?
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
A
B
C
D
E
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
4.
An arrow of mass m and speed v0 strikes and sticks to one end of a meterstick of mass M as shown in the
diagram above. The meterstick is initially at rest on a horizontal surface and free to move without friction.
The speed of the center of mass of the stick-arrow system after the arrow strikes is given by which of the
following expressions?
A
B
C
D
E
0
A wheel of mass m, which has a rotational inertia I and a radius r, rotates with an angular speed ω about an axis
through its center. A retarding force F is applied tangentially to the rim of the wheel.
5. The retarding force F finally stops the rotation of the wheel. Which of the following best represents the total
reduction in mechanical energy in the process of stopping the wheel?
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
A
Fr
B
Iω2
C
ωr
D
Fr2
2
E
A solid disk of mass , radius and rotational inertia is free to rotate about a fixed frictionless axis that is
perpendicular to the disk through its center, as shown above. A force of constant direction and constant magnitude
is exerted on the disk.
6.
If the disk accelerates from rest at time
, through what angle
does the disk rotate from
?
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to
AP Physics C: Mechanics
Test Booklet
In-Class Review 5
A
B
C
D
E
7.
A rotating platform with a radius of
platform is most nearly
makes one complete turn every
. The angular velocity of the
A
B
C
D
E
8.
Two blocks, one of mass
and one of mass
, are connected by a massless string over a pulley that is a
uniform disk of mass
and moment of inertia
. The two masses are released from rest, and the
masses accelerate as the pulley rotates. Assume there is negligible friction between the pulley and the axle.
What is the linear acceleration, , of the masses?
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
A
B
C
D
E
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
9.
Two blocks of masses m1 and m2 are connected by a massless string that passes over a wheel of mass m, as
shown above. The string does not slip on the wheel and exerts forces T1 and T2 on the blocks. When the
wheel is released from rest in the position shown, it undergoes an angular acceleration and rotates
clockwise. Which of the following statements about T1 and T2 is correct?
A
T1 = T2 because the wheel has mass.
B
T1 = T2 because both blocks have the same acceleration.
C
T1 > T2 because m1 is farther from the wheel than m2.
D
T1 > T2 because m1 accelerates upward.
E
T2 > T1 because an unbalanced clockwise torque is needed to accelerate the wheel clockwise.
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
10.
A wheel of radius R is fixed to an axle of radius R/3 and rotates at constant angular speed ω , as shown in
the figure above. A force of magnitude F1 is applied tangent to the outer edge of the wheel. A second force
of magnitude F2 is applied tangent to the edge of the axle to keep the wheel rotating at constant angular
speed ω. The magnitude F2 is equal to
A
F1/9
B
F1/3
C
F1
D
3F1
E
9F1
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
11.
A motor drives a shaft of radius
that is attached to the center of a wheel of radius . The motor is
turned off, and the force that the motor exerts on the shaft,
, varies with time, as shown. There is also
a constant friction force of
applied to the rim of the wheel in the opposite direction of the motion.
During which time interval does the rotational kinetic energy increase and then decrease?
A
From
to
B
From
to
C
From
to
D
From
to
E
From
to
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
12.
In an experiment, students roll several hoops down the same incline plane. Each hoop has the same mass but
a different radius. Each hoop rolls down the incline without slipping. Which of the following graphs best
shows the linear speed of the hoops at the bottom of the incline as a function of the radius of the hoop?
A
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
B
C
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
D
E
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
13.
Four round objects of equal mass and radius roll without slipping along a horizontal surface that then bends
upward and backward into an arc of half a circle. The objects all have the same linear speed initially. The
objects are a hollow cylinder, a solid cylinder, a solid sphere, and a hollow sphere. The objects to go up the
arc and exit the arc going in the opposite direction they entered without falling off the arc. Now, several
trials are run for each object. For each trial, the initial speed of the object is reduced until the object does not
make it through the full arc. The speed needed for each object to just make it through the arc is recorded.
Which of the following correctly lists the objects in order from fastest to slowest speed needed to make it
through the arc?
A
Hollow cylinder, hollow sphere, solid cylinder, solid sphere
B
Hollow cylinder, solid sphere, solid cylinder, hollow sphere
C
Solid sphere, solid cylinder, hollow sphere, hollow cylinder
D
Solid sphere, hollow sphere, solid cylinder, hollow cylinder
E
Hollow sphere, solid cylinder, hollow cylinder, solid sphere
14. A hoop of mass m and radius r rolls with constant speed on a horizontal surface without slipping. What is
the hoop’s translational kinetic energy divided by its rotational kinetic energy?
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AP Physics C: Mechanics
Test Booklet
In-Class Review 5
A
4
B
2
C
1
D
1/2
E
1/4
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