Chapter 10, Problem 10MCP

A heavy solid disk rotating freely and slowed only by friction applied at its outer edge takes 100 seconds to come to a stop. If the disk had twice the radius and twice the mass, but the friction force remained the same, the time it would take the wheel to come to a stop from the same initial rotational speed is

1. A.    25 s.
2. B.     100 s.
3. C.     400 s.
4. D.    800 s.