A 28 g block sits at the center of a turntable that rotates at 60 rpm. A compressed spring shoots the block radially outward from the center along a frictionless groove in the surface of the turntable. Calculate the turntable's angular speed when the block reaches the outer edge. Treat the turntable as a solid disk with mass with mass 200 g and diameter 44.0 cm. Express your answer in revolutions per minute.

Question

A 28 g block sits at the center of a turntable that rotates at 60 rpm.  A compressed spring shoots the block radially outward from the center along a frictionless groove in the surface of the turntable.  Calculate the turntable's angular speed when the block reaches the outer edge.  Treat the turntable as a solid disk with mass with mass 200 g and diameter 44.0 cm.  Express your answer in revolutions per minute.

bobpursley · Answer

final momentum=initialmomentum final momentkum= 1/2 (.2*.44)w+.028*w initial momentum= 1/2 (.2*.44)60 set them equal, solve for w. Notice at the center, r=0, so the block has no angular momentum.