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JEE Main202623 January 2026Morning ShiftPhysicsRotational MotionActual

Two small balls with masses m and 2 m are attached to both ends of a rigid rod of length d and negligible mass. If angular momentum of this system is L about an axis ( A ) passing through its centre of mass and perpendicular to the rod then angular velocity of the system about A is :

Options

  1. A2 L 5 m d²
  2. B4 3 L m d²
  3. C3 2 L m d²
  4. D2 L m d²

Correct answer

C. 3 2 L m d²

Step-by-step solution

CM from mass m : x_ cm = 2md 3m = 2d 3 . Distances: m is 2d/3 from CM, 2m is d/3 from CM. I_ cm = m(2d/3)^2 + 2m(d/3)^2 = 4md^2 9 + 2md^2 9 = 2md^2 3 . L = I = L I = 3L 2md^2 .

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