A student sits on a rotating stool and is given a speed of 1.20 rev/sec. His hands are held away from his body, giving him a moment of inertia of 1.70 kgm^2. He then pulls his arms in closer to his axis of rotation, changing his moment of inertia to 0.90 kgm^2. Find the student's rotational speed after pulling in his arms. Find the initial and final kinetic energies (in Joules).