Compute all parts of following problem:
Problem: A small button placed on a horizontal rotating platform with diameter 0.305 m will revolve with the platform when it is brought up to a speed of 24.0 rev/min, provided the button is no more than 0.147 m from the axis.
Part A: What is the coefficient of static friction between the button and the platform?
Part B: How far from the axis can the button be placed, without slipping, if the platform rotates at 39.0 rev/min?
I need help to find the coefficient of static friction between the button and the platform.