Consider a merry-go-round of mass m mgr and radius R mgr that is rotating freely as sketched in...

Angular Momentum on the Playground

Consider a merry-go-round of mass m_mgr and radius R_mgr that is rotating freely as sketched in Figure 9.11. A child is eager to enjoy a ride, so she steps onto the edge of the merry-go-round. After she gets on, she notices that the angular velocity of the merry-go-round has decreased slightly. If the child’s mass is mc, what is the ratio of the final angular velocity to the initial angular velocity?

Figure 9.11 Example 9.4. A child steps onto a rotating merrygo- round.