# Rolling puck on a spinning disk

## Homework Statement

A small puck is placed on a disk spinning with angular speed OMEGA around axis perpendicular to the disk and passing through its center. The coefficient of static friction between the disk and the puck is MU. At what distance(s) from the center of the disk will the puck be at rest?

## Homework Equations

Rotational Inertia of Rotating Disk:

I=(1/2)*M*R^2

Force of Static Friction

F=MU*(NORMAL FORCE)

## The Attempt at a Solution

By "at rest" I believe it means when the puck is rolling ON the spinning disk in a way that keeps it in the same place. But I have no idea how to determine the distance the puck needs to be at for that to happen.

Look at the puck on the spinning disk, what forces act on it? In order for it to be rotating with angular speed $$\omega$$ at a distance $$R$$ from the center of the disk, what must the force towards the center of the disk be?