What's the difference between elastic and inelastic collisions? Is momentum always conserved in both scenarios?
Elastic Collision is the collision in which colliding objects rebound without lasting deformation or heat generation. Kinetic energy and momentum are both conserved. No energy is lost to things like deformation. Collisions between hard objects like billiard balls tend to be elastic.
Inelastic collision is a collision in which the colliding objects become distorted and generate heat during collision and possibly stick together. Momentum is still conserved, but kinetic energy is not. Some kinetic energy is lost to deformation.