A merry-go-round with R = 2 m and moment of inertia I = 300 kg m^2. Ignore friction at the axle so that there are no external torques that slow the motion of the merry-go-round.
The merry-go-round is rotating initially with ω_i = 1 rad/s. A 40 kg girl runs at a speed of 4 m/s in a straight line tangential to the edge and jumps on the edge.
(a) Explain why angular momentum of the merry-go-round and the girl is conserved.
(b) What is the initial angular momentum?
(c) Find the angular velocity after she jumps on?