Collision with diagonal surface

Ok, I'm having a bit of a problem with this.

A ball is dropping in free fall (not spinning/rotating or anything).
After a given time it collides with a diagonal surface (a total inelastic collision), it then begins to roll down from it.

How do I find the velocity that it begins to roll down the diagonal surface with? Do I just regard the ball's velocity as a vector and find the component that is parallel to the surface?

>>11
That's a dangerous way to think about it. It's easy to see if you transform frames, to a frame where the ball is not falling straight but perpendicular to the slope. Naturally, it will stop completely (as you said earlier). But as this frame is moving parallel to the slope, in the frame where it is falling straight, it will continue to move with a speed parallel to the slope.