**Goal:** Problem solving using conservation of angular momentum.

**Source:** UMPERG

A bug walks on a freely rotating disk. Given: M_{bug}=0.05 kg,

I_{disk}=0.03 kg-m2, R_{disk}=0.5 m, and

ω_{o}= 2 rad/s when bug is 0.1 m from center. The bug

crawls to 0.4 m from the disk’s center. The final ω is most

nearly:

- 1.6 rad/s
- 1.2 rad/s
- 1.0 rad/s
- 0.8 rad/s
- 0.5 rad/s
- None of the above
- Cannot be determined

## Commentary:

## Answer

(1) This is a very traditional conservation of angular momentum problem.

The only difficulty is due to the presence of extraneous information.

Some students may use conservation of energy.