Suppose the platform of the previous problem is brought to rest with the bail in the hand of the kid standing on the rim. The kid throws the ball horizontally to his friend in a direction tangential to the rim with a speed u as seen by his friend. Find the angular velocity with which the platform will start rotating.

Given:


Mass of the ball= m


Velocity of the ball = v


Radius of the platform= R


Initial Angular momentum= mvR


Since external torque is zero,


Initial angular momentum = Final angular momentum


Therefore, angular momentum =




1