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Question
What do you mean by the conservation of momentum? Briefly, explain the collision between two bodies and the conservation of momentum.
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Solution
Conservation of momentum in case of a collision between two bodies means the total momentum before and after collision remains unchanged or conserved, provided no net force acts on the system.
Consider two bodies A and 8 having masses m1 and m, and initial velocities u1 and u, respectively. The bodies collide head on with each other and their collision lasts for t seconds. Suppose the velocities of A and 8 after collision are v1 and v, respectively. Assume that no external forces are acting on the bodies.
Rate of change of momentum of ball A = m1(v1 - u1)/t .
Rate of change of momentum of ball 8 = m1 (v1 - u1)/t .
If FAB is the force exerted by A on 8 and FBA is the force ex
Rated by 8 on A, we can write
FAB= m1(v1 - u1)/t .
FBA = m1 (v1 - u1)/t .
FAB = -FBA
m1(v1 - u1)/t = - m2(v2- u2)/t .
m1(v1 - u1) = - m2(v2- u2)
m1v1 +m2v2 = m1u1+m2u2
So total momentum after collision = total momentum before collision.
This proves conservation of momentum during collision.
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