You stand on a frictionless platform that is rotating with an angular speed of {eq}3.9rev/s {/eq}. Your arms are outstretched, and you hold a heavyweight in each hand. The moment of inertia of you, the extended weights, and the platform is {eq}7kg/m^2 {/eq}. When you pull the weights in toward your body, the moment of inertia decreases to {eq}5.2 kg / m^2 {/eq}.
a) What is the resulting angular speed of the platform? Answer in units of {eq}rev/s {/eq}.
b) What is the change in kinetic energy of the system? Answer in units of J.