AP Physics C: Mechanics / Unit 4: Linear Momentum
4.4 Elastic and Inelastic Collisions
Notes
- Elastic: kinetic energy is conserved.
- Inelastic: KE is not conserved. Perfectly inelastic: objects stick together.
- Momentum is conserved in all collisions (isolated system).
Practice
A 2 kg cart at 6 m/s sticks to a 1 kg cart at rest. Final speed:
$12=3v$.
In a perfectly inelastic collision:
Maximum KE loss.
Which is conserved in every isolated collision?
Always momentum.
In a 1D elastic collision, a ball hits an identical ball at rest. After:
Equal masses exchange velocities.
Ready for more? Take the Unit 4 test.