An inelastic collision is a type of interaction where momentum is conserved, but kinetic energy is not. During such collisions, some of the kinetic energy is transformed into other forms of energy—such as heat, sound, or deformation of the colliding objects.
This means that while the total momentum of the system before and after the collision remains the same (as long as no external forces act), the total kinetic energy decreases.
A special case of an inelastic collision is a perfectly inelastic collision, where the colliding objects stick together after impact and move as a single combined mass.
Examples include:
- A lump of clay hitting and sticking to a wall,
- A car crash where vehicles crumple and lock together,
- Certain particle interactions in nuclear physics.
Inelastic collisions are common in the real world, where ideal energy conservation is rare. They help explain many physical processes involving energy dissipation, friction, and material deformation.