That depends: did the passengers come to a halt too, or did one or more of them fly out the windshield?

Does that even matter?

haha no..

lol ok, just checking...

The answer, of course, is 14.08 m/s in the opposite direction of the first car.

Isn't that right? It better be.. I'm taking the Physics 2 "Mechanics w/ Calculus" AP test next month..

You're right... I'm talking to Duki on the phone and he said you are correct.

yay! My question is:

The position vector of a particle of mass 3kg is given by r(vector)= 4i+3t^2j, where r is in meters and t is in seconds. Determine the angular momentum and torque acting on the particle about the origin.

If you were worried about details, it would matter. The passengers were part of the energy system, and stopping them would require energy as well. If passengers from one vehicle were to continue flying through the windshield, it would change the amount of energy involved in the collision, and would change the result a bit.