**Goal:** Problem solving with rotational dynamics

**Source:** UMPERG-ctqpe148

A hoop

of mass 4 kg and radius 10 cm rolls without slipping down an incline

30° to the horizontal. The acceleration of the center of the hoop

is most nearly

- 10 m/s
^{2} - 5 m/s
^{2} - 3.5 m/s
^{2} - 2.5 m/s
^{2} - none of the above
- cannot be determined

## Commentary:

## Answer

(4) Students should realize that the acceleration must be less

than a sliding mass on a frictionless surface would have which is #2.

Engage the students in a discussion of why the acceleration cannot

depend upon the radius.