A nonuniform 2-0 kg rod is 2.0 m long. The rod is mounted to rotate freely about a horizontal axis perpendicular to the rod that passes through one end of the rod. The moment of inertia of the rod about this axis is 4.0 kg.m2. The center of mass of the rod is 1.2 m from the axis. If the rod is released from rest in the horizontal position, what is its angular speed as it swings through the vertical position?
The Attempt at a Solution
I tried to use conservation of energy but I am not really sure whether the height in the potential energy initially is the distance from the center of mass to the rotational axis or the length of the rod...????