A2L Item 080

Goal: Problem solving using conservation of angular momentum.

Source: UMPERG

A bug walks on a freely rotating disk. Given: Mbug=0.05 kg,
Idisk=0.03 kg-m2, Rdisk=0.5 m, and
ωo= 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

  1. 1.6 rad/s
  2. 1.2 rad/s
  3. 1.0 rad/s
  4. 0.8 rad/s
  5. 0.5 rad/s
  6. None of the above
  7. Cannot be determined



(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.