A thin rod of length L and negligible mass can pivot about oneend to rotate in a vertical circle. A heavy ball of mass m isattached to the other end. The rod is pulled aside through anangle A and released. As the ball descends to its lowestpoint,
a.) how much work does its weight do on it and
b.) what is the change in the gravitational potential energyof the ball-Earth system?
c.) If the gravitational potential energy is taken to be zeroat the lowest point, what is its value just as the ball isreleased?