Question

The total momentum of the two cars before a collision is 100 KG M/S. What is the total momentum of the two cards after they collide?

0KG M/S

Answer 1

AFTER the collision, there is no momentum.

Answer 2

Momentum before = momentum after if there is no net force on system
(Newton ONE)

Answer 3

If they were both going at twenty right toward each other (opposite velocities with same mass)
momentum before = 20 * m - 20 * m = 0 = momentum after
I think that is what PsyDAG is assuming