Description
Use conservation of momentum to find unknown velocities after collisions and explosions. In this AP Physics C: Mechanics video, we build a step-by-step method (draw before and after, choose a system, write p before = p after, solve and check units) and apply it to carts that stick together, rain falling into a cart, spring-loaded carts pushed apart, and a two-dimensional collision where momentum is conserved separately in the x and y directions. We also see why momentum is conserved but kinetic energy is not in a perfectly inelastic collision.
In this video:
0:00 Hook: two carts and a spring
2:25 Strategy for conservation of momentum problems
3:15 Perfectly inelastic collisions
3:55 Explosions and recoil
4:13 Example: sticky carts
6:46 Example: rain falling into a cart
8:53 Example: spring-loaded carts
10:21 Example: two-dimensional collision
13:24 Preview: designing an experiment
Download the guided notes and practice problems for this unit at houstonscience.com.
Part of the AP Physics C: Mechanics Unit 4 (Linear Momentum) series.