Question

state and prove law of conservation of linear momentum ​

Answer 1

Law of conservation of momentum states that total momentum of system remains conserved in absence of external force.

Proof- Consider a body of mass m1 moving with velocity striking against another body of mass m2 moving with velocity.

Answer 2

Newton's third law states that for a force applied by an object A on object B, object B exerts back an equal force in magnitude, but opposite in direction. This idea was used by Newton to derive the law of conservation of momentum. ... B=m_{2}(v_{2}-u_{2}) (change in momentum of particle B)