Two children (m = 31.0 kg each) stand opposite each other on the edge of a merry-go-round. the merry-go-round, which has a mass of 1.78 ✕ 10^2 kg and a radius of 1.2 m, is spinning at a constant rate of 0.48 rev/s. treat the two children and the merry-go-round as a system. (a) calculate the angular momentum of the system, treating each child as a particle. (give the magnitude.) (b) calculate the total kinetic energy of the system. (c) both children walk half the distance toward the center of the merry-go-round. calculate the final angular speed of the system.