Science
Elastic and inelastic collisions.
Definition
In elastic collisions, both momentum and kinetic energy are conserved, and objects bounce apart. In inelastic collisions, momentum is conserved but kinetic energy is not—some energy is converted to heat, sound, or deformation. A perfectly inelastic collision is one where the objects stick together.
Examples
Real-world.
- 1 Two billiard balls colliding approximate an elastic collision
- 2 A car crash where the vehicles crumple is an inelastic collision—kinetic energy converts to deformation
- 3 Two clay balls that stick together after colliding is a perfectly inelastic collision
Key Fact
Elastic: KE conserved (KE_before = KE_after); Inelastic: KE not conserved; Perfectly inelastic: objects stick together (maximum KE loss).