Full Speed Ahead!

Now, imagine the following situation:
You're driving a bumper car. In front of you is another bumper car with two of your friends. Your two friends are, of course, twice as heavy as you. Nevertheless you are on collision course. The speed of your car and the speed of your friends' car is the same. Now, think thoroughly! What will happen after the collision?
What do you think? What velocity will the two cars have after the collision?
Here is another model experiment with its picture. The big car is lighter and resembles your own bumper car, the blue car is heavier and resembles your friends' bumper car.
In this experiment the blue car has about twice the mass of the bigger car. Now it's your turn! What will happen after the collision?

a) After the collision both cars just change their direction (they both move in the opposite direction, i.e. backwards) but they both have the same speed.

b) The heavy (blue) car changes its direction (opposite direction...backwards) and it moves faster after the collision because it received momentum from the lighter car. The lighter (bigger) car moves more slowly afterwards or it even stops moving.

c) The lighter (green) car moves on in the opposite direction and receives additional speed due to the collision because the heavier car has transferred some of its momentum onto the lighter car. That's also the reason why the heavier (blue) car moves more slowly or stops moving altogether.