System Open or Closed#
Two cars collide on a track. Car A comes up behind car B and runs into it. Car A has mass of kg, car B has mass of kg. The following graph shows the velocity of each car as a function of time.

Question Text#
Is the system isolated? Why or why not?
Answer Section#
Yes, because the two carts are on a track with no friction.
Yes, because their change in velocities are the same.
No, because the total momentum is nonzero.
No, because the momentum is not conserved
Attribution#
Problem is licensed under the CC-BY-NC-SA 4.0 license.