A block is placed on a horizontal turntable at a distance of 50 mm from the central axle. When the turntable rotates, the block is just on the point of sliding when the speed of rotation is 1.4 rev/s....

A block is placed on a horizontal turntable at a distance of 50 mm from the central axle. When the turntable rotates, the block is just on the point of sliding when the speed of rotation is 1.4 rev/s. What is the coeffcient of friction between the block and turntable surfaces?