252 Forensic Engineering Fundamentals
is topic is very important and needs further clarication. Since the impulses of the
forces are equal and opposite, the vector change in momentum of either vehicle, in any
time interval, is also equal in magnitude and opposite in direction to the vector change
in momentum of the other. us, the net change in momentum of the colliding bodies,
the system, must be zero. Since the pair of action-reaction forces are internal forces of the
system and since the total momentum of the system cannot be changed by internal forces,
and since the only forces acting on the system are internal forces, the total momentum of
the system must remain constant in magnitude and direction. Keep in mind that in such
a collision ...