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    • Abstract: Date Period NameCHAPTER8 Study GuideRotational MotionVocabulary ReviewWrite the term that correctly completes the statement. Use each term once.

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Date Period Name
CHAPTER
8 Study Guide
Rotational Motion
Vocabulary Review
Write the term that correctly completes the statement. Use each term once.
angular acceleration centrifugal “force” Newton’s second law for
angular displacement Coriolis “force” rotational motion
angular velocity lever arm radian
center of mass moment of inertia torque
1. Angular acceleration is directly proportional to the net torque and
inversely proportional to the moment of inertia is a statement of
.
2. As an object rotates, the change in angle is called .
3. The of a rotating object can be calculated by dividing its
angular displacement by the time it takes for the displacement to
occur.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. The of an object is the point on the object that moves in the
same way that a point particle would move.
5. The is the resistance to rotation.
1
6. The is of a revolution of a spinning object.
2
7. The apparent force that seems to pull an object on a spinning plat-
form toward the outside of the platform is called the .
8. The result of dividing the change in angular velocity by the time it
takes to make the change is .
9. is the measure of how effectively a force causes rotation.
10. When a force is exerted on a rotating object, the change in angular
velocity depends on the , which is the perpendicular distance
from the axis of rotation to the point where the force is exerted.
11. When the horizontal motion of an object in a rotating frame of
reference seems to deflect, the apparent force is the .
Physics: Principles and Problems Chapters 6–10 Resources 79
Name
8 Study Guide continued
Section 8.1 Describing Rotational Motion
In your textbook, read about rotational motion on pages 197–200.
Refer to the diagram at right to answer questions 1–7. If the statement
is true, write true. If the statement is false, rewrite the italicized part to B
make it true.
1. If a point on the car moving along the edge of the circle rotates
r A
from point A to point B in a counterclockwise direction, its
angular displacement is positive.
5
2. The value of is approximately rad.
4
3. The variable r represents the distance the point moves as the circle rotates.
4. The actual distance the point travels is its angular displacement.
5. Angular displacement is measured in meters.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
6. If it takes 4 s for the point to move so that , its angular velocity is rad/s.
4
5
7. If the point is at rest at A and it has an angular velocity of rad/s when it reaches point B 2 s
4
10
later, it has an angular acceleration of rad/s2.
4
Section 8.2 Rotational Dynamics
In your textbook, read about torque and net torque on pages 201–204.
Answer the following questions. Use complete sentences.
1. Sometimes sit-ups are done with your arms out in front of you, and sometimes they are done with
your hands behind your head. In terms of torque, why is it less difficult to do a sit-up with your
arms out in front of you?
80 Chapters 6–10 Resources Physics: Principles and Problems
Name
continued Study Guide 8
2. Can a force of 400 N exert a greater torque than a force of 900 N? Explain your answer.
3. Latoya has two batons. Baton A has identical round objects on each end. The round objects on the
ends baton B are unequal in size and mass.
a. When Latoya holds each of the batons in the middle, which one has net torque equal to zero?
Explain your answer.
b. How can Latoya hold baton B so that it has net torque equal to zero?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. Barbara exerts a force of 48 N on the outer edge of a door that is 76 cm wide. What is the torque if
the force is perpendicular to the door?
In your textbook, read about the moment of inertia on pages 205–210.
For the objects described in questions 5–12, write the formula you would use to calculate the moment of
inertia.
Calculate the moment of inertia for each. Show your calculations.
5. A solid rubber ball has a radius of 32 cm and a mass of 0.85 kg with the axis of rotation through
the center.
Physics: Principles and Problems Chapters 6–10 Resources 81
Name
8 Study Guide continued
6. A metal hoop has a diameter of 4.0 m and a mass of 1.2 kg with the axis of rotation through the
central diameter.
7. A broom handle has a length of 1.67 m and a mass of 580 g with the axis of rotation through the
center.
8. A piece of aluminum foil has a length of 7.2 cm, a width of 4.5 cm and a mass of 50.0 g with the
axis of rotation through the center.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
9. A 12-cm slice of a tree trunk has a radius of 48 cm and a mass of 12 kg with the axis of rotation
through the center.
10. A metal rod has a length of 1.3 m and a mass of 2.8 kg with the axis of rotation through the end.
11. A flat cookie sheet has a length of 35 cm, a width of 22 cm, and a mass of 467 g with the axis of
rotation through the center.
12. A pencil lead has a mass of 0.66 g and a length of 12.6 cm with the axis of rotation through the
center.
82 Chapters 6–10 Resources Physics: Principles and Problems
Name
continued Study Guide 8
Section 8.3 Equilibrium
In your textbook, read about the center of mass and how it affects stability on pages 211–213.
Write the term that correctly completes the statement.
The point on an object that moves in the same way that a point particle would move is the
(1) of the object. To find the center of mass of an object, first
suspend the object from (2) . When the object is not moving,
draw a(n) (3) from the suspension point. Repeat this process
using another (4) . The center of mass is the point at which
(5) . The center of mass of an adult human who is standing with
his or her arms hanging down is about halfway between the front and the back of the body, a
few centimeters below the (6) .
In an unstable object, the center of mass is (7) the base of an object.
However, an object is stable if a(n) (8) is required to tip it over.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
A force acts on an object and applies a(n) (9) on the object. The
(10) of the object applies a torque in the opposite direction, as it
acts on the (11) of the object. When the object tips enough that
its center of mass is no longer above its (12) , both torques act
in (13) direction(s), and the object tips over. A(n)
(14) base results in a stable object. An object is also more likely
to be stable if its center of mass is located (15) in the object.
In your textbook, read about the conditions for equilibrium on pages 213–215.
Answer the following questions. Use complete sentences.
16. What can be said about the velocity and angular velocity of an object that is in static equilibrium?
17. When is an object in translational equilibrium?
Physics: Principles and Problems Chapters 6–10 Resources 83
Name
8 Study Guide continued
18. When is an object in rotational equilibrium?
In your textbook, read about rotating frames of reference, centrifugal “force,” and the Coriolis “force”
on pages 216–217.
Circle the letter of the choice that best completes the statement.
19. Newton’s laws do not apply to a spinning object, because rotating frames of reference are
frames.
a. inertial c. non-accelerated
b. accelerated d. static
20. If you triple the rotational frequency, the centripetal acceleration .
a. increases by a factor of 4 c. increases by a factor of 9
b. decreased by a factor of 4 d. decreases by a factor of 9
21. The apparent force that makes objects seem to be pulled toward the outer edge of a rotating object
is .
a. the Coriolis “force” c. centripetal acceleration
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
b. centrifugal “force” d. a rotating frame of reference.
22. One condition for the appearance of the Coriolis “force” is .
a. a rotating reference frame c. vertical motion
b. centripetal acceleration d. straight horizontal movement
23. To an observer stationed on a rotating object, a ball that is thrown across the object appears to
.
a. follow a straight path c. have varying speed
b. have vertical motion d. follow a curved path
24. The Coriolis “force” makes winds rotate in the northern hemisphere.
a. clockwise around low-pressure c. clockwise around high-pressure areas
areas
b. counterclockwise around d. counterclockwise around high-pressure areas
low-pressure areas
84 Chapters 6–10 Resources Physics: Principles and Problems


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