Answer
Because of the principle of inertia, the cars continue moving until a sufficient force has caused them to stop. The contact force between the cars at the moment of collision starts to slow them down.
Before this force has stopped the cars completely they will have moved some distance. The back end continues to move but the front end is crushed till it comes to rest.
Work Step by Step
Because of the principle of inertia, the cars continue moving until a sufficient force has caused them to stop. The contact force between the cars at the moment of collision starts to slow them down.
Before this force has stopped the cars completely they will have moved some distance. The back end continues to move but the front end is crushed till it comes to rest.
