A2L Item 083

Goal: Reasoning with dynamics.

Source: UMPERG

A child stands on a spinning disk. Suppose that there is friction
between the child’s shoes and the surface of the disk. While holding a
rock the child stands at the largest radius possible for the current
angular velocity without slipping. After releasing the rock, the child

  1. lose traction and slide off the disk.
  2. lose traction, slide towards center.
  3. remain on disk and able to move out.
  4. remain on disk, unable to move out.



(4) There should be no consequence of dropping the rock. Because the
normal force changes, so does the friction force. The new friction force
is still able to provide the necessary centripetal force for the
circular motion.