**Goal:** Problem solving with rotational kinematics

**Source:** UMPERG-ctqpe110

A flywheel rotating about an axis through its center starts from rest,

rotates with constant angular acceleration for 2 seconds while making

one complete revolution and thereafter maintains constant angular

velocity. How long does it take the wheel to make a total of 6 full

revolutions?

- 4 secs
- 5 secs
- 6 secs
- 7 secs
- 9 secs
- None of above
- Cannot be determined

## Commentary:

## Answer

(4) This problem provides an excellent opportunity to discuss the power

of graphs for problem solving. Making a sketch of angular velocity vs.

time provides the easiest way to answer the problem. Conversely, an

algebraic solution is complicated.