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## Homework Statement

A hockey player of mass 8.0x10 kg was skating at a velocity of 7.5 m/s [E] when he accidentally hit a linesman who was just standing on the ice. The mass of the linesma is 9.0x10 kg and his velocity after the collision was 3.0 m/s [N30°E].

a) find the velocity of the hockey player after the collision

b) find the kinetic energy lost during the collision

## Homework Equations

p=p'

p=mv

0.5mv

^{2}= v

## The Attempt at a Solution

since momentum is conserved: (horizontal E (+) direction)

P

_{b}=P

_{a}

m

_{A}v

_{A}+ m

_{B}v

_{B}= m

_{B}v

_{B}' + m

_{A}v

_{A}'

80kg(7.5m/s) + 0kgm/s = 90cos 30° + 80vAcosθ

600-90cos30°= 80v

_{A}cosθ

(600-90cos30°)/80 = v

_{A}cosθ

6.5 m/s = v

_{A}cosθ

I'm not really sure about what to do next, do i just continue with finding the v

_{A}sinθ for the same direction and then do the same things for the vertical direction? Are there any other solid steps that i need to know in order to solve a 2D momentum question?

Thanks