rotational kinetic energy: an extremely light rod 1.00 m long has a 2.00-kg mass attached to one end and a 3.00-kg mass attached to the other. the system rotates at a constant angular speed about a fixed axis perpendicular to the rod that passes through the rod 30.0 cm from the end with the 3.00-kg mass attached. the kinetic energy of the system is measured to be 120.0 j. (a) what is the moment of inertia of this system about the fixed axis? (b) what is the angular speed (in revolutions per second) of this system?