A toy car and a toy truck at rest have a compressed spring in between them. The truck has more mass than the car. The spring is released and the two cars move in opposite directions. Which of the following is true?
A) The magnitude of the truck's momentum is the same as the car's.
B) The magnitude of the truck's momentum is larger than the car's.
C) The magnitude of the truck's momentum is smaller than the car's.
D) It is not possible to tell which has more momentum without knowing the speeds.

Question

Quizplus · Accepted Answer

According to the law of conservation of momentum, the total momentum of a system remains constant if no external forces act on it. When the spring is released, the momentum transferred to the truck is equal in magnitude but opposite in direction to the momentum transferred to the car, making their momenta equal in magnitude.

A Toy Car and a Toy Truck at Rest Have