Two small balls A and B, each of mass m, are joined rigidly at the ends of a light rof of length L. they are placed on a frictionless horizontal surface another ball of mass 2 m moving with speed u towards one of the ball and perpendicular to the length of the rod on the horizontal frictionless surface as shown int he figure. if the coefficient of restitution is 1/2 then the angular speed of the rod after the collision will be

Options

A. `(4)/(3)(u)/(L)`
B. `(u)/(L)`
C. `(2)/(3)(u)/(L)`
D. none of these

Answer

C

Explanation

velocity of ball 'A' just after the collision `V=(1+(1)/(2)).(2)/(3)u=u`
Velocity of ball 'B' just after the collision =0
`thereforeomega(u-0)/(L)=(u)/(L)`