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JEE Main20248 Apr 2024Evening ShiftPhysicsRotational MotionActual

A thin circular disc of mass M and radius R is rotating in a horizontal plane about an axis passing through its centre and perpendicular to its plane with angular velocity . If another disc of same dimensions but of mass M / 2 is placed gently on the first disc co-axially, then the new angular velocity of the system is :

Options

  1. A3 2
  2. B5 4
  3. C2 3
  4. D4 5

Correct answer

C. 2 3

Step-by-step solution

aligned & I ₁ = I ₂ ₂ & MR ^2 2 = 3 2 ( MR ^2 2 ) ₂ & ₂= 2 3 aligned

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