A2L Item 101

Goal: Reason with rotational dynamics.

Source: UMPERG-ctqpe136

A spool has string wrapped around its center axle and is sitting on a
horizontal surface. If the string is pulled in the horizontal direction
when tangent to the top of the axle, the spool will

  1. roll to the right.
  2. not roll, only slip.
  3. roll to the left.
  4. cannot be determined.



(1) For many students this remains counterintuitive.