The Question: A 45kg child runs at 3.0m/s and jumps tangentially onto a stationary merry-go-round. The moment of inertia of the merry-go-round is 360 kgm^2 and the radius is 2.0m. What is the angular velocity of the child and the merry-go-round? My attempts: I'm not sure how to incorporate the speed of the running child into this question. I've made some attempts at getting the answer but none included the speed of the running child, and I know it has to include it. First I tried solving this with respect to conservation of angular momentum...but I got nowhere with that. I'm pretty sure it has something to do with conservation of angular momentum but I can't figure out where to start with the question. Anyone's help would be appreciated.