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Highly selective Backlog Qs for JEE MainPhysicsCenter of Mass, Momentum and Collision

Two particles A   &   B , initially at rest, move towards each other under mutual force of attraction. At an instance when the speed of A is v and the speed of B is 2 v , the speed of centre of mass (COM) is

Options

  1. Azero
  2. Bv
  3. C2 . 5 v
  4. D4 v

Correct answer

A. zero

Step-by-step solution

Initially, both the particles are at rest, therefore, velocity of centre of mass is zero. There is no external force on the system. Summation of all internal forces in a system is always zero. So, speed of centre of mass remains constant, i.e., it should be equal to zero.

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