Get velocity on collision time

Hi. I have a physics object (A) set in motion by a Physics Impulse at an angle. I want to get the velocity of the object when it collides with another Physics object (B) and use the value to decide whether B should be destroyed or just bounce off A. How do I get the velocity? <img src="smileys/smiley23.gif" border="0" align="middle" />

distance(0,0,object.physics.vexctorX,object.physics.vectorY) will give you the velocity.

Thanks a bunch!