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JEE Main202118 Mar 2021Evening ShiftPhysicsCenter of Mass, Momentum and CollisionActual

An object of mass m 1 collides with another object of mass m 2 , which is at rest. After the collision the objects move with equal speeds in opposite direction. The ratio of the masses m 2 : m 1 is :

Options

  1. A3 : 1
  2. B2 : 1
  3. C1 : 2
  4. D1 : 1

Correct answer

A. 3 : 1

Step-by-step solution

m 1 v 1 = - m 1 v + m 2 v v 1 = - v + m 2   m 1 v v 1 + v v = m 2   m 1 e = 2 v v 1 = 1 v = v 1 2 v 1 + v 1 / 2 v 1 / 2 = m 2   m 1 3 = m 2   m 1

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