Question

state and prove law of conservation of momentum.

Answer 1

Law of conservation of momentum is more basic than third law of motion. However here we derive the law of conservation of momentum from the third law of motion.

Let us suppose a body of mass m1 travelling with velocity u1 collides with another body of mass m2 and travelling with velocity u2. After collision let the first body changes its velocity to v1 and the second body to v2.

Since there is change in velocity of the either bodies there must be change in momentum and force experienced by both of them due to each other.

Answer 2

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Conservation 0f Momentum➫ A system in which the momentum of a system is constant if there are no external forces acting on the system.

Prove: Conservation 0f Momentum:-▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃⤵

➧Let the Body A = m1 & B = m2

➧Let their velocity be u1 & u2
(u1 > u2)

➧Momentum of Body
A = m1u1 & B = m2u2

❱ Initial & Final momentum of System
➾ m1u1 + m2u2

◉ Body A exert force of Action
➾ Fᴀʙ on Body B.

◉ Body B exert force of Reaction
➾ Fʙᴀ on Body A.

▸ Fᴀʙ = Body A
➾ m1 (v1 - u1) / t

▸ Fʙᴀ = Body B
➾ m2 (v2 - u2) / t

▸ Since, Action = - reaction
▸ So, Fᴀʙ = - Fʙᴀ

m1 (v1 - u1) / t = - m2 (v2 - u2) / t

▸ m1v1 - m1u1 = m2v2 + m2u2
▸ m1v1 - m2v2 = m1u1 + m2u2...✔

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Thanks...✊