Question
Two cars (A and B) of mass 1.5 kg collide. Car A is initially moving at 24 m/s, and car B is initially moving in the opposite direction with a speed of 12 m/s. The two cars are moving along a straight line before and after the collision. (a) If the two cars have an elastic collision, calculate the change in momentum of the two-car system. (b) If the two cars have a completely inelastic collision, calculate the change in momentum of the two-car system.
Question by OpenStax is licensed under CC BY 4.0
Final Answer

This is a closed system. Momentum will be conserved, so there will be no change in momentum in either case.

Solution video

OpenStax College Physics for AP® Courses, Chapter 8, Problem 22 (Test Prep for AP® Courses)

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Video Transcript
This is College Physics Answers with Shaun Dychko. Two cars—one labeled A and the other labeled B— both have a mass of 1.5 kilograms and they collide and car A is initially moving at 24 meters per second and car B is initially moving towards it with the speed of 12 meters per second and in part (a), the two cars have an elastic collision, calculate the change in momentum and if the two cars have a completely inelastic collision, calculate the change of momentum of the two car system but there isn't much to do here because it's a closed system, there's no external net force involved and so momentum will be conserved meaning there will be no change in momentum in either case and so case closed!