The object shown in the figure below consists of a thin rod of length = 23.3 cm and mass m = 1.20 kg with a solid ball of diameter d = 10.0 cm and mass M = 2.00 kg attached to its top. The object is free to pivot about a frictionless axle through the bottom of the rod. The object is initially vertical and at rest when it starts to rotate clockwise. After the combination rotates through 90 degrees, what is its rotational kinetic energy (in J)