Static Friction Coefficient

1. The problem statement, all variables and given/known data
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.

3. 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.


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

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