State law of conservation of momentum. Deduce this law from Newton’s second law of motion.
Law of conservation of momentum.
The law states that if a number of bodies are interacting with each other, that is, the bodies are exerting forces on each other, their total momentum remains conserved before and after the interaction, provided there is no external force acting on them.
Derivation using Newton’s second law of motion:
Let p1 and p2 represent the sum of momenta of a group of objects before and after the collision, respectively.
Let t be the time elapsed during the collision.
According to Newton’s second law of motion,
External force = Rate of change of momentum
Hence, in the absence of an external force, the total momentum of a group of objects remains unchanged or conserved during the collision.
This is the law of conservation of momentum.
