Conservation Of Energy

Equate the momenta of the system along two perpendicular axes. Let be the velocity and the direction of the third piece as shown.
Equating the momenta of the system along OA and OB to zero, we get ..(i)
and ..(ii)
These give or

Thus,
Putting the value of in E (i), we get

The third piece will go with a velocity of

in a direction making an angle of with either piece.
The square of momentum of third piece is equal to sum of squares of momentum first and second pieces. As from key idea,
or or or

The block will experience maximum upward force, when the ball P is at its lowest position (x). Energy conservation gives or ?(i) For the block Q to leave contact Solving Eqs. (i) and (ii), we get