Question

A coin is placed on a turntable that is rotating at 33.3 rpm

Answer 1

It will slip at a distance of 4 cm. When angular velocity is doubled, centrifugal force becomes four times because centrifugal force is proportional to square of angular velocity. To keep the centrifugal force same on the coin, the radial distance will have to be reduced to 1/4 of original distance i.e 1/4 x 16 = 4 cm.