A disk-shaped merry-go-round of radius 2.63 m and mass 155 kg rotates freely by an angular speed of 0.712 rev/s. A 59.4 kg person running tangential to the rim of the merry-go-round at 2.76 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 decrease, increase, or stay the same when the person jumps on the merry-go-round?