A disk-shaped merry-go-round of radius 2.63 m and mass 155 kg rotates freely with an angular speed of 0.596 rev/s. A 59.4 kg person running tangential to the rim of the merry-go-round at 3.68 m/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.

Question

A disk-shaped merry-go-round of radius 2.63 m and mass 155 kg rotates freely with an angular speed of 0.596 rev/s. A 59.4 kg person running tangential to the rim of the merry-go-round at 3.68 m/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. 
(a) Does the kinetic energy of the system increase, decrease, or stay the same when the person jumps on the merry-go-round?

(b) Calculate the initial and final kinetic energies for this system. 
Ki = kJ 
Kf = kJ

I will be happy to critique your efforts. On the first question, think out what the system is. Does the system include the person running?