A2L Item 105

Goal: Problem solving

Source: UMPERG-ctqpe147

A hoop of mass 4 kg and radius r rolls
without slipping down an incline 30° to the horizontal. The hoop is
released from rest. What is the speed of the hoop after its center has
fallen a distance h?

  1. (4g(h-r))1/2
  2. (2gh)1/2
  3. (gh)1/2
  4. (0.5g(h+r))1/2
  5. none of the above
  6. cannot be determined



(3.) Students should realize that the speed cannot depend upon the
radius. Answer #2 is the speed that a falling point mass would have and
the hoop must have less than that.