STATEMENT OF PROBLEM

The following specifications were taken for a certain model of video cassette recorder.
Tape Speed: 1.3125 inches per second
Play Time: 2 hours
Radius of tape spindle: 12 mm
Outer radius of wound tape: 43 mm

1) How thick is the tape?

2) Derive a function that gives the tape spindle driver speed (in rotations per minute -- rpm) as a function of the radius. Note that the tape speed is constant.