A disk-shaped merry-go-round of radius 2.78mand mass 160kg rotates freely with an angular speed of 0.696rev/s . A 60.8kg person running tangential to the rim of the merry-go-round at 3.19m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the same direction as the merry-go-round's rim.
What is initial and final kinetic energy?