Question

A coin is placed on a large disk which rotates uniformly at a rate of 2 rot/s. The coefficient of friction between the coin and the disk is 0.1. To what distance from the center of the disk should the coin be placed so that the coin may not slip?

I know that mu times g (.1 x 9.8) would go on top, but I don't know what the denominator would be.

Answer 1

the angular speed, or 4pi

Answer 2

the denominator would be the rot/s so the answer would be (ug)/(rot/s)=(.1*9.8)/2=.49 meters from the center