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AP®︎ Physics 1: Topic 5.4 Practice Test

Prepare for your quiz, test, or the AP exam with focused practice questions on Topic 5.4 of AP Physics 1 – Rotational Inertia.

Questions List

Topic 5.4

Q10

Q11

Q12

Q13

Q14

Q15

Q16

Question 1 Easy

Wheels A and B rotate about low-friction axles. Wheel A has greater rotational inertia about its axle than wheel B has about its axle. Initially, both wheels spin counterclockwise: A at

12\ \text{rad/s}

and B at

4\ \text{rad/s}

. The same counterclockwise net torque is exerted on each wheel for

2.0\ \text{s}

.

Which of the following must be true?

AAfter the torque acts, wheel A has a smaller angular speed than wheel B.

BThe angular speed of wheel A increases by less than that of wheel B.

CThe angular speed of wheel A increases by more than that of wheel B.

DThe angular speeds of both wheels increase by the same amount.

What You’re Being Tested On:

Explore the learning objectives taken directly from the College Board’s AP® Physics 1 Curriculum. Ensure you’re prepared for the exact topics covered on the AP® exam, in-class tests, and quizzes, and gain confidence in your mastery of the material.

Topic 5.4: Rotational Inertia

Boundary Statements official exam scope notes

AP Physics 1 only expects students to calculate the rotational inertia for systems of five or fewer objects arranged in a two-dimensional configuration. Students do not need to know the rotational inertia of extended rigid systems, as these will be provided within the exam. Students should have a qualitative understanding of the factors that affect rotational inertia; for example, how rotational inertia is greater when mass is farther from the axis of rotation, which is why a hoop has more rotational inertia than a solid disk of the same mass and radius.

Learning Objective: 5.4.A

Describe the rotational inertia of a rigid system relative to a given axis of rotation.

Essential Knowledge: 5.4.A.1

Rotational inertia measures a rigid system’s resistance to changes in rotation and is related to the mass of the system and the distribution of that mass relative to the axis of rotation.

Essential Knowledge: 5.4.A.2

The rotational inertia of an object rotating a perpendicular distance $r$ from an axis is described by the equation $I = mr^2$ .

Essential Knowledge: 5.4.A.3

The total rotational inertia of a collection of objects about an axis is the sum of the rotational inertias of each object about that axis: $I_{tot} = \sum I_i = \sum m_i r_i^2$

Learning Objective: 5.4.B

Describe the rotational inertia of a rigid system rotating about an axis that does not pass through the system’s center of mass.

Essential Knowledge: 5.4.B.1

A rigid system’s rotational inertia in a given plane is at a minimum when the rotational axis passes through the system’s center of mass.

Essential Knowledge: 5.4.B.2

The parallel axis theorem uses the following equation to relate the rotational inertia of a rigid system about any axis that is parallel to an axis through its center of mass: $I' = I_{cm} + Md^2$

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AP®︎ Physics 1: Topic 5.4 Practice Test

Question 1 Easy

What You’re Being Tested On:

Learning Objective 5.4.A: 5.4.A.1, 5.4.A.2, 5.4.A.3

Learning Objective 5.4.B: 5.4.B.1, 5.4.B.2