A 38-kg boy running at 3.7m/s jumps tangentially onto a small circular merry-go-round of radius 2.0 m and rotational inertia 20 kg? m2 pivoting on a frictionless bearing on its central shaft. Merry-go-round initially rotating at 0.70rad/s opposite the direction that the boy was running before he jumped on it.
1. Find the change in the boy's kinetic energy.
2. Discover the change in the kinetic energy of the merry-go-round.
3. Decide the rotational speed of the merry-go-round after the boy jumps on it.
4. Discover the change in kinetic energy of the system consisting of the boy and the merry-go-round.