Mouse Speed

I’m looking to make a movie clip react to the collision of a another movie clip that is being dragged by the mouse cursor. i’ve been able to do this with the hittest in actionscript. Now what i want is the movie clip being “HIT” to react to how fast the cursor is moving when its being hit. I know its possible but i’m in the dark on this one. If anyone could shed some light on this it would be greatly appreciated!!..

thanks