Two carts on a level track collide head-on. After the collision, cart 1 is completely at rest, and cart 2 has?

Question

Two carts on a level track collide head-on. After the collision, cart 1 is completely at rest, and cart 2 has reversed direction. Which cart’s momentum changed by the greatest amount during the collision? Or did both carts’ momentum change by the same amount? Explain.

Answer 1

Both had the same change in momentum because they were the only bodies in the collision and momentum lost by one went to the other. The heavier cart stopped and the lighter one bounced back.

Answer 2

total momentum will be constant.

Change in momentum for both would be same.(you need to take into consideation the direction as momentum is a vector quantity)