A 4.5 m diameter merry-go-round is rotating freely with an angular velocity of 0.70 rad/s. Its total moment of inertia is 1800 kg*m^2. Four people standing on the ground, each of mass 62 kg, suddenly step onto the edge of the merry-go-round.
What is the angular velocity of the merry-go-round now?
What if the people were on it initially and then jumped off in a radial direction (relative to the merry-go-round)?