Momentum & Pulleys Homework: Solving for Velocity

[cupid.callin]

Homework Statement

The Attempt at a Solution

Taking the pulley and strings, pan, ball, block as system ... momentum is conserved

therefore in Y direction(vertical) ...

-mv = -2mV + mV
-mv = -mV
v = V

which is incorrect (as i expected as there has to be some loss of velocity of particle in a collision)

How should i do it?

 

[ashishsinghal]

Try doing this using impulse:
Let the time of collision be dt and force be F.
Use F.dt = change in momentum for all the 3 bodies, then find the final velocity.

 

[ashishsinghal]

Try doing this using impulse:
Let the time of collision be dt and force be F.
Use F.dt = change in momentum for all the 3 bodies, then find the final velocity.

WARNING: This method by me is a general method of solving collision questions. This is not to be used blindly in this case. Consider the forces which brings the change in momentum.