Consider the following: Two cars colliding head-on ==================> v1=30 & v2=(-30) One car colliding with parked car ===========> v1=60 & v2=0 Two cars colliding, one into rear of other ==> v1=120 & v2=60 What are the differences between the four cases? Note, velocity difference between the 2 cars is the same in all cases. (e.g. delta v = 60) Eric R. Kissell 1986 5000cstq, 1.8 bar, k24