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MHT CET202617 April 2026Evening ShiftPhysicsRotational MotionActual

Radius of gyration of a thin uniform circular disc about the axis passing through its centre and perpendicular to its plane is K_c . Radius of gyration of the same disc about a diamter of the disc is K_d . the ratio K_d : K_c is

Options

  1. A1 : 4
  2. B1 : 2
  3. C2 : 1
  4. D2 : 1

Correct answer

B. 1 : 2

Step-by-step solution

Moment of inertia of a uniform circular disc about an axis passing through its centre and perpendicular to its plane is I_c = 1 2 MR^2 . Radius of gyration K_c = I_c M = R 2 . Moment of inertia of the disc about its diameter is I_d = 1 4 MR^2 . Radius of gyration K_d = I_d M = R 2 . Ratio K_d K_c = R 2 R 2 = 1 2 . Thus, K_d : K_c = 1 : 2 . Answer: 1 : 2

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