# Homework Help: Inelastic collision

1. Jul 20, 2008

### ally1h

1. The problem statement, all variables and given/known data
A 2.0 kg object is moving at 5.0 m/s NORTHWEST. It strikes a 6.0 kg object that is moving SOUTHWEST at 2.0 m/s. The objects have a completely inelastic collision. The velocity of the 6.0 kg object post collision is:

2. Relevant equations
m1v1+m2v1 = m1v2+m2v2

3. The attempt at a solution
I know the answer to be 2.33 m/s at 14 degrees North of West. I don't know how to get there. I THOUGHT, since the collision is inelastic, the equation is m1v1+m2v1=(m1+m2)v, and solve for v. That tells me the velocity of both the objects to be 3.2 m/s. Then I think I have to approach this collision from a 2 dimension perspective... but without angle to go off of, I am lost! Please help!

2. Jul 20, 2008

### Staff: Mentor

You most definitely must treat momentum as a vector. Treat north-south and east-west components separately. You are given all the angles that you need--translate southwest and northwest into angles.