A student stands on a platform that is rotating without friction at 1.2 rev/s. His arms are outstretched and he holds a brick in each hand. The rotational inertia of the system (students, bricks and platform) about the central vertical axis is 6.0 kg-m^2. She moves the bricks inwards and reduces the rotational inirtia of the system to 2 kg- m^2.
what is the new angular speed of the system?
what is the ratio of the new system kinetic energy to the original system kinetic energy
what causes this chance in KE