The figure shows a thin rod, of length L = 1.6 m and negligible mass, that…

The figure shows a thin rod, of length L = 1.6 m and negligible
mass, that can pivot about one end to rotate in a vertical circle.
A heavy ball of mass m = 9.1 kg is attached to the other end. The
rod is pulled aside to angle θ0 = 6.4° and released with initial
velocity v Overscript right-arrow EndScripts Subscript 0 = 0. As
the ball descends to its lowest point, (a) how much work does the
gravitational force do on it and (b) what is the change in the
gravitational potential energy of the ball-Earth system? (c) If the
gravitational potential energy is taken to be zero at the lowest
point, what is its value just as the ball is released?