# Static Friction Coefficient

#### DoctorB2B

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.

#### rl.bhat

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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