Question

Describe momentum and conservation of mumentum.

Describe the difference between an elastic and inelastic collision. (mention which conserves kinetic energy)

Answer 1

The momentum of a particle is a vector quantity which is equal to the product of its mass times its velocity (p = m*v). The momentum of a system is the vector sum of the momenta of the objects which make up the system. For an isolated system (no other external forces are acting on the system), the momentum of the system is constant which implies that momentum is conserved. In simple terms, momentum lost by one (or more) of the objects in a system is gained by the other objects.

In both perectly elastic and inelastic collisions, the momentum is conserved. However, in elastic collision, there is no loss of kinetic energy (kinetic energy is conserved), where as in inelastic collision, some part of kinetic energy is lost in heat or friction (some other forms of energy). In elastic collision, there is no dissipative force acting during the collision.