There are four answers required for this question. A playground merry-go-round (like a disk) has a mass of 220 kg and a diameter of 4.4 meters is rotating at 30 rpm. Four children, each having a mass of 30 kg, run and jump on the merry-go-round at a tangential velocity equal to its velocity. Assume they are evenly spaced around the merry-go-round and it has frictionless bearings.
a. What is the rotational kinetic energy of the merry-go-round before the children jump on?
b. What is the angular momentum of the merry-go-round before the children jump on?
c. What is the angular momentum of the merry-go-round after the children jump on?
d. What is the rotational kinetic energy of the merry-go-round after the children jump on?