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.
Why ω rises when I falls
K = L²/2I
A sliding block beats every roller
Ball strikes a pivoted rod: the three moves
Angular momentum
Angular impulse
Total kinetic energy of a rolling object
Torque does work only through an angle
Angular momentum in orbits
Moment of inertia depends on the axis
Angular momentum units
Angular impulse from a torque–time graph
Short answer 1. Define or explain: Rotational kinetic energy
3 ptsShort answer 2. Define or explain: Why a diver tucks
3 ptsShort answer 3. Define or explain: Comparing linear and rotational analogues
3 ptsShort answer 4. Define or explain: Torque, angular momentum and the second law
3 ptsFree response
7 ptsA 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.