Description
Momentum and Kinetic Energy: Same p or Same K? - AP Physics C Mechanics 4.1b
Description
Momentum and kinetic energy both depend on mass and speed, but not in the same way. In this AP Physics C: Mechanics video, we compare a linebacker and a wide receiver, derive K = p²/2m and p = √(2mK), and use functional dependence to compare objects with the same momentum or the same kinetic energy. We finish by predicting how p and K change when mass or speed changes, and then return to the hook: which player is harder to stop?
In this video:
0:00 Hook: linebacker vs. wide receiver
2:07 Two different measures of motion (vector vs. scalar, v vs. v²)
3:04 Deriving K = p²/2m and p = √(2mK)
4:15 Functional dependence: same momentum vs. same kinetic energy
5:13 Example: same momentum (ratio of kinetic energies)
6:26 Example: same kinetic energy (ratio of momenta)
7:38 Example: factors of change
9:32 Back to the hook: which one is harder to stop?
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.