A 4.4 diameter merry-go-round is rotating freely with an angular velocity of 0.63 . Its total moment of inertia is 1800 . Four people standing on the ground, each of mass 66 , suddenly step onto the edge of the merry-go-round.
Funny, I just got to this problem in my physics homework.
Use the Conservation of angular momentum idea, L=Iw. You can find this with your given initial values. Then, you use that L in a new equation, except with the I final and w final (which you want to ultimately find).
Use I=mr^2 to find the mass of the merry-go-round. Take that mass and add 4*66. Plug back into equation for new finaly I. (Remember to change the diameter to radius)
Use the L and final I to find final w.