How Do You Calculate Final Velocities in a Two-Mass Elastic Collision?

[davev]

http://i.minus.com/i7YDkagp0bChQ.png

Homework Equations

p = mv

(v1m1 + v2m2)
Vf = --------------------
(m1+m2)

The Attempt at a Solution

I got that the total momentum was 9.64 by using p=mv for summing m1, v1 and m2, v2. Then I used inverse trig to try to find the angle, but all the answers I submit are incorrect. I'm not sure what way to go here.

 

[ehild]

The momentum is vector, and the momentums sum as vectors.

ehild

 

[davev]

All the answers are still positive, so I don't understand what you mean.

 

[ehild]

How do you add two vectors?

ehild