How Much Static Friction is Needed for a Penny to Stay on a Rotating Record?

[DoctorB2B]

Homework Statement

What is the minimum coefficient of static friction necessary to allow a penny to rotate without sliding off a 33.5rpm record (diameter of these old-fashioned records is 0.3), when the penny is placed at the edge of the record. Ignore the size of the penny.

The Attempt at a Solution

I know the equation to determine the static friction coefficient. However, I am clueless as to how to proceed from here.

 

[rl.bhat]

Which force slides off the penny from the record? What is its magnitude?
What is the direction and magnitude of the frictional force?