Unit 6: Energy and Momentum of Rotating Systems
Physics 1 · Unit 6 · Paper 3

Energy and Momentum of Rotating Systems unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 42 terms and is the same for everyone, so a teacher can assign “Unit 6, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 34 min 31 points0/17 attempted
1

Why kinetic energy is lost in a rotational collision

2

Rotational kinetic energy

3

Comparing linear and rotational analogues

4

Angular momentum

5

A system that is both rolling and colliding

6

Torque, angular momentum and the second law

7

Angular momentum units

8

Rolling race

9

Rotational work and power

10

The condition for angular momentum conservation

11

Torque does work only through an angle

12

Rolling down a ramp by energy

Short answer 1. Define or explain: Work done by a torque

3 pts

Short answer 2. Define or explain: Why ω rises when I falls

3 pts

Short answer 3. Define or explain: A particle moving in a straight line has angular momentum

3 pts

Short answer 4. Define or explain: Where to strike a pivoted rod for maximum effect

3 pts

Free response

7 pts

A solid disk and a hollow hoop have the same mass M and radius R. Both are released from rest at the top of an incline of height h and roll without slipping to the bottom. (a) Explain, without calculation, why both objects arrive with less translational speed than a frictionless sliding block released from the same height. (b) Derive an expression for the translational speed at the bottom in terms of M, R, h, g and the moment of inertia I. (c) Use your expression to determine which object arrives first, and justify why the result does not depend on M or R.

Explain, without calculation, why both objects arrive with less translational speed than a frictionless sliding block released from the same height.

Derive an expression for the translational speed at the bottom in terms of M, R, h, g and the moment of inertia I.

Use your expression to determine which object arrives first, and justify why the result does not depend on M or R.