A kid of mass M stands at the edge of a platform of radius R which can be freely rotated about its axis. The moment of inertia of the platform is I . The system is at rest when a friend throws as ball of mass m and the kid catches it. If the velocity of the ball is v horizontally along the tangent to the edge of the platform when it was caught by the kid find the angular speed of the platform after the event.

Answer

B

Explanation

A kid of mass M stands at tehedge of the platform of a raduis R which has a moment of inertia I. S ball thrown to him and with horizontal velocity of the ball -v when we catches it.
Therefoe if we take the total bodies as a system
`mvR={1+(M+m)R^2}omega`
The moment of inerti aofkid adn ball about the axis=`(M+m)R^2`
`rarr omega=(mvR)/(1+(M+m)R^2)`