A small block of mass m=0.032kg can slide along a frictionless loop-the-loop, with the loop radius R=12cm. The block is released from rest at point...

A small block of mass m=0.032kg can slide along a frictionless loop-the-loop, with the loop radius R=12cm. The block is released from rest at point P, at height h=5R above the bottom of the loop. How much work does the gravitational force do on the block as the block travels from point P to point Q?