Homework Help: Conservation Of Momentum

1. The problem statement, all variables and given/known data
This diagram shows a white snooker ball moving with a velocity of [itex]3.2 \ ms^{-1}[/itex]. The white ball is on a collision course with a stationary blue ball of identical mass of [itex]0.173 \ kg[/itex]. The player is aiming to propel the blue ball into the pocket along the path shown.

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The player succeeds in propelling the blue ball along the path shown. The blue ball has a velocity of [itex]2.77 \ ms^{-1}[/itex] after the collision with the white ball. Calculate the velocity of the white ball after the collision.


2. Relevant equations
[itex]P=mv[/itex] (I think)


3. The attempt at a solution
As momentum is conserved, I would have momentum before equals momentum after hence...

[itex](0.173)(3.2) = (0.173)(v) + (0.173)(2.77) \implies v = 0.43 \ ms^{-1}[/itex]

But this is incorrect. Can someone explain how I would tackle this question and point out my mistake. Thanks in advance. (The correct answer is [itex]v = 1.6 \ ms^{-1}[/itex].)