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 1 Paper 2 Paper 3

Each paper is built from this unit’s 34 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 35 min 32 points0/17 attempted

Angular momentum in an elliptical orbit

Work–energy theorem for rotation

Rotational power

Rotational work and power

Precession qualitatively

Rotational analogue table

Choosing the point for angular momentum

Why kinetic energy is not conserved when I changes

Gyroscopic precession

Energy change when I changes

Particle striking a pivoted rod

Conservation of angular momentum

Short answer 1. Define or explain: Angular impulse

3 pts

Short answer 2. Define or explain: Rotational work

3 pts

Short answer 3. Define or explain: Angular momentum of a point particle

3 pts

Short answer 4. Define or explain: Rolling race is independent of mass and radius

3 pts

Free response

8 pts

QUALITATIVE/QUANTITATIVE TRANSLATION (Question 4, 8 points). A unicycle is placed on a stand so its wheel does not touch the ground; the wheel's rotational inertia about the axle is I_W. A crank arm attaches to the wheel, and a force of magnitude F is exerted at the arm's end, always perpendicular to the arm. Each crank arm has negligible mass; the wheel starts at rest each time. Scenario 1: arm length ℓ1; after the crank arm turns through one rotation the wheel's angular speed is ω1. Scenario 2: arm length ℓ2 > ℓ1; after one rotation the angular speed is ω2. Scenario 3: the unicycle is on the ground and rolls forward without slipping while the same force F is applied to the ℓ1 arm; after one rotation the wheel's angular speed is ω3.

A. Indicate whether ω2 is greater than, less than, or equal to ω1, and justify with conceptual reasoning beyond algebraic solutions.

B. Derive an expression for ω1 in Scenario 1 immediately after one rotation of the crank arm, in terms of I_W, F, ℓ1, and physical constants, as appropriate.

C. Indicate whether ω3 is greater than, less than, or equal to ω1, and briefly justify with conceptual reasoning beyond algebraic solutions.