Question

a) When is the momentum of a system conserved?

b) If the momentum of the system is conserved, can the momentum of various objects within the system change?

c) What is an elastic collision?

d) Is momentum conserved in an elastic collision?

Answer 1

A) If the external forces acting on a system add up to zero then linear momentum of system reamins constant.

b) Yes, momentum of various object within a conserved system can change. If momentum of a body increases than momentum of another body decreses to conserve the total momentum of the system.

c)An elastic collision is a collision in which there is no net loss in kinetic energy in the system after the collision.In real world, most collisions result in loss of kinetic energy in the form of heat and sound, so mostly collisions are inelastic.

d)Yes, both momentum and kinetic energy are conserved in elastic collisions.