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Question 30556
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Center of Mass, Momentum and Collision: JEE — COM Frame KE MCQ

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JEE — COM Frame KEHardQuestion 30556

Question

In the centre of mass frame, the minimum total KE of a system of two bodies is:
  1. A
    Greater than zero always
  2. B
    Equal to the KE of their relative motion
  3. C
    Zero (COM frame always has zero KE)
    Correct
  4. D
    ½(m₁+m₂)v_cm²

Correct answer

Zero (COM frame always has zero KE)

Explanation

In the COM frame, the total momentum = 0, and the minimum KE (at closest approach in a collision) is zero. The KE in the COM frame is the KE of relative motion.

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