THE PRACTICE STUDIO
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PRACTICE / Angular momentum conservation
Why does pulling inward increase rotational energy?
A rotating system changes its moment of inertia from 0.60 kg m² to 0.30 kg m² by pulling masses inward. Initially it rotates at 4 rad/s.
What is the ratio of final to initial rotational kinetic energy?
Organize the givens & assumptions
- Ii = 0.60 kg m²
- If = 0.30 kg m²
- ωi = 4 rad/s
External torque about the fixed rotation axis is negligible. The system rotates about that same axis before and after the change.
- A
- B
- C
- D
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