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MHT CET20244 May 2024Evening ShiftPhysicsRotational MotionActual

A thin uniform circular dise of mass ' M ' and radius ' R ' is rotating with angular velocity ' ' in a horizontal plane about an axis passing through its centre and perpendicular to its plane. Another disc of same radius but of mass ( M 3 ) is placed gently on the first disc co-axially. The new angular velocity will be

Options

  1. A2 3
  2. B3 4
  3. C4 3
  4. D5 4

Correct answer

B. 3 4

Step-by-step solution

Angular momentum = I By conservation of angular momentum, aligned & I ₁ ₁= I ₂ ₂ & Here, I₁= M R^2 2 , I₂= (M+M / 3) 2 R^2= 2 M R^2 3 & MR ^2 2 ₁= 2 MR ^2 3 ₂ & ...[From(i)] & ₂= 3 4 ₁= 3 4 ( ₁= ) aligned

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