Archer sliding backward firing an arrow using momentum conservation

[dandy9]

Homework Statement

A 64.2kg man fires a .3kg arrow. The arrow is measured to have a velocity of 63m/s by a stationary bystander. All these happen while the archer sliding backwards at -.26m/s. What will be his velocity (in the x-direction) after firing this arrow?

Homework Equations

pbefore = pafter

The Attempt at a Solution

I used the eq'n m1v1 + m2v2 = m1v1' + m2v2'
I was able to solve the left side to be 2.208.
But I'm unsure of what to use for v2' on the right side... The arrow surely doesn't still fly at 63m/s right? Nor does it come to rest?

Thank you!

 

[ashishsinghal]

v2' will be 63m/s.why do you have a doubt here. what have you taken as v2