Hey I'm new here I have a question that is bothering me, so here it is: Q: A playground merry-go-round of radius R = 2.15 m has a moment of inertia of I = 214 kg·m2 and is rotating at 13.4 rev/min about a frictionless vertical axle. Facing the axle, a 20.4 kg child hops onto the merry-go-round and manages to sit down on its edge. Find the work done by the child. A: Now the first part of this question was also to find the final anguar speed of the merry go round which i found to be 9.30 rev/min, or 0.974 rad/s which is the right answer. Now at first I thought this was going to be easy enough and that the work done would equal the change in Kinetic energy of the system since that is the only thing slowing it down. However i seem to be mistaken as I just keep getting this question wrong. Any help would be appreciated, this is for a quiz due in a couple days. Thanks!