a student, sitting on a stool rotating at a rate of 20 RPM holds masses in each hand. when his arms are extended, the total rotational inertia of the...

a student, sitting on a stool rotating at a rate of 20 RPM holds masses in each hand. when his arms are extended, the total rotational inertia of the system is 4.5 kg/m^2. he pulls his arms in close to his body, reducing the total rotational inertia to 1.5kg/m^2. if there are no external torques, what is the new rotation velocity of the system.