A small button placed on a horizontal rotating platform with diameter 0.316 m will revolve with the platform when it is brought up to a rotational speed of 39.0 rev/min, provided the button is a distance no more than 0.140 m from the axis. (Take the free fall acceleration to be g = 9.80 m/s^2.)
What is the coefficient of static friction between the button and the platform?
How far from the axis can the button be placed, without slipping, if the platform rotates at 59.0 rev/min?