Explain how the principle of conservation of momentum applies to a collision between two vehicles. Include the role of momentum before and after the collision in your answer.

In a collision between two vehicles, the total momentum before the collision is equal to the total momentum after the collision, assuming no external forces act on the system. This means that the momentum lost by one vehicle is gained by the other, demonstrating that momentum is conserved.

This question assesses the understanding of the conservation of momentum principle in real-world scenarios. It requires students to articulate how momentum is transferred between colliding objects while remaining constant in a closed system.