Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) When a rigid object rotates about a fixed axis, what is true about all the points in the
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object? (There could be more than one correct choice.)
A) They all have the same angular speed.
B) They all have the same angular acceleration.
C) They all have the same tangential acceleration.
D) They all have the same radial acceleration.
E) They all have the same tangential speed.
2) Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater
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distance from the axis of rotation than Jacques. Which of the following are true
statements? (There could be more than one correct choice.)
A) Jacques and Ahmed have the same angular speed.
B) Jacques and Ahmed have the same tangential speed.
C) Jacques has a greater angular speed than Ahmed.
D) Ahmed has a greater tangential speed than Jacques.
E) Jacques has a smaller angular speed than Ahmed.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
3) A car is traveling along a freeway at 65 mph. What is the linear speed, relative to
the highway, of each of the following points on one of its tires?
(a) the highest point on the tire
(b) the lowest point on a tire
(c) the center of the tire
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3)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
4) The figure below shows scale drawings of four objects, each of the same mass and
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uniform thickness, with the mass distributed uniformly. Which one has the greatest
moment of inertia when rotated about an axis perpendicular to the plane of the drawing
at point P?
A)
A
B) B
C) C
D) D
E) The moment of inertia is the same for all of these objects.
5) Consider a uniform hoop of radius R and mass M rolling without slipping. Which is
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larger, its translational kinetic energy or its rotational kinetic energy?
A) Both are equal.
B) Translational kinetic energy is larger.
C) Rotational kinetic energy is larger.
D) You need to know the speed of the hoop to tell.
6) Consider a solid uniform sphere of radius R and mass M rolling without slipping.
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Which form of its kinetic energy is larger, translational or rotational?
A) Rotational kinetic energy is larger.
B) Translational kinetic energy is larger.
C) Both are equal.
D) You need to know the speed of the sphere to tell.
7) A solid sphere and a solid cylinder, both uniform and of the same mass and radius, roll
without slipping at the same forward speed. It is correct to say that the total kinetic
energy of the solid sphere is
A) less than the total kinetic energy of the cylinder.
B) more than the total kinetic energy of the cylinder.
C) equal to the total kinetic energy of the cylinder.
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8) A disk and a hoop of the same mass and radius are released at the same time at the top
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of an inclined plane. If both are uniform, which one reaches the bottom of the incline
first if there is no slipping?
A) The disk
B) The hoop
C) Both reach the bottom at the same time.
9) A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the
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three of them are released simultaneously at the top of an inclined plane and do not slip,
which one will reach the bottom first?
A) pipe
B) cylinder
C) sphere
D) The pipe and cylinder arrive together before the sphere.
E) They all reach the bottom at the same time.
10) A disk, a hoop, and a solid sphere are released at the same time at the top of an inclined
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plane. They are all uniform and roll without slipping. In what order do they reach the
bottom?
A) sphere, disk, hoop
B) hoop, disk, sphere
C) hoop, sphere, disk
D) sphere, hoop, disk
E) disk, hoop, sphere
11) A small uniform disk and a small uniform sphere are released simultaneously at the top
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of a high inclined plane, and they roll down without slipping. Which one will reach the
bottom first?
A) the disk
B) the one of greatest mass
C) the one of smallest diameter
D) the sphere
E) They will reach the bottom at the same time.
12) Suppose a uniform solid sphere of mass M and radius R rolls without slipping down an
inclined plane starting from rest. The linear velocity of the sphere at the bottom of the
incline depends on
A) neither the mass nor the radius of the sphere.
B) the mass of the sphere.
C) both the mass and the radius of the sphere.
D) the radius of the sphere.
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13) Suppose a solid uniform sphere of mass M and radius R rolls without slipping down an
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inclined plane starting from rest. The angular velocity of the sphere at the bottom of
the incline depends on
A) the mass of the sphere.
B) both the mass and the radius of the sphere.
C) neither the mass nor the radius of the sphere.
D) the radius of the sphere.
14) A uniform ball is released from rest on a no-slip surface, as shown in the figure below.
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After reaching its lowest point, the ball begins to rise again, this time on a frictionless
surface. When the ball reaches its maximum height on the frictionless surface, it is
A)
higher than when it was released.
B) at the same height from which it was released.
C) lower than when it was released.
D) It is impossible to tell without knowing the mass of the ball.
E) It is impossible to tell without knowing the radius of the ball.
15) Two uniform solid balls, one of radius R and mass M, the other of radius 2R and mass
8M, roll down a high incline. They start together from rest at the top of the incline.
Which one will reach the bottom of the incline first?
A) Both reach the bottom at the same time.
B) The large sphere arrives first.
C) The small sphere arrives first.
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15)
16) The rotating systems shown in the figure differ only in that the two identical movable
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blocks are positioned a distance r from the axis of rotation (left), or a distance r/2 from
the axis of rotation (right). If you release the hanging blocks simultaneously from rest,
A)
the block at the right lands first.
B) the block at the left lands first.
C) both blocks land at the same time.
17) A person sits on a freely spinning lab stool that has no friction in its axle. When this
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person extends her arms,
A) her moment of inertia increases and her angular speed remains the same.
B) her moment of inertia increases and her angular speed decreases.
C) her moment of inertia increases and her angular speed increases.
D) her moment of inertia decreases and her angular speed increases.
E) her moment of inertia decreases and her angular speed decreases.
18) A merry-go-round spins freely when Diego moves quickly to the center along a radius
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of the merry-go-round. As he does this, it is true to say that
A) the moment of inertia of the system decreases and the angular speed remains the
same.
B) the moment of inertia of the system decreases and the angular speed decreases.
C) the moment of inertia of the system increases and the angular speed decreases.
D) the moment of inertia of the system decreases and the angular speed increases.
E) the moment of inertia of the system increases and the angular speed increases.
19) If the answer to your calculation has units of kg m2/s, what type of quantity could it
be? (There could be more than one correct choice).
A) power
B) moment of inertia
C) work
D) force
E) rotational kinetic energy
F) angular momentum
G) torque
H) linear momentum
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20) If the answer to your calculation has units of kg m2/s2 , what type of quantity could it
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be? (There could be more than one correct choice.)
A) power
B) linear momentum
C) angular momentum
D) rotational kinetic energy
E) moment of inertia
F) torque
work
G)
H) force
21) A spinning ice skater is able to control the rate at which she rotates by pulling in her
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arms. Which of the following statements are true about the skater during this process?
(There could be more than one correct choice.)
A) Her moment of inertia remains almost constant.
B) She is subject to a constant non-zero torque.
C) Her kinetic energy remains almost constant.
D) Her angular momentum remains almost constant.
22) When
is the angular momentum of a system constant?
A) Only when the moment of inertia is constant.
B) Only when its total kinetic energy is constant.
C) Only when no net external torque is exerted on the system.
D) Only when the linear momentum and the energy are constant.
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Answer Key
Testname: UNTITLED1
1) A, B
2) A, D
3) (a) 130
4) B
5) A
6) B
7) A
8) A
9) C
10) A
11) D
12) A
13) D
14) C
15) A
16) A
17) B
18) D
19) F
20) D, F, G
21) D
22) C
mph
(b) 0 mps
(c) 65 mph
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