A child (mc = 36 kg) is playing on a merry-go-round (mm = 225 kg, R = 2.9m) that is initially at rest. The child then jumps off in a direction tangent to the edge of the merry-go-round. The child has a speed of 5.0 m/s just before she lands on the ground. What is the magnitude of the final angular velocity of the merry-go-round?
L = I*ω
Li,c + Li,m = Lf,c + Lf,m
I = (1/2)mmR2 for the merry-go-round.
I = mcR2 for the child.
The Attempt at a Solution
The initial angular momentum of the system is 0 so Li,c + Li,m = 0.
So Lf,c + Lf,m = 0
(1/2)mmR2 * ωf + mcR2 * ωf = 0
(1/2)mmR2 * ωf = - mcR2 * ωf
However when I plug the values for mass of the merry-go-round and the child as well as the radius for the merry-go-round I cannot seem to find a way to isolate ωf to one side of the equation, I just keep getting 0 rad/s.