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Concepts Of Physics MCQ Edition [Volume 1]PhysicsRotational Mechanics

Determine the radius of gyration of a circular ring of radius r about a line perpendicular to the ring's plane and passing through one of its particles.

Options

  1. A2 ,r
  2. Br 2
  3. Cr
  4. D3 2 ,r

Correct answer

A. 2 ,r

Step-by-step solution

The moment of inertia of a circular ring of mass M and radius r about an axis passing through its centre and perpendicular to its plane is I_ cm = M r^2 . Using the parallel axis theorem, the moment of inertia of the ring about an axis passing through a particle on its circumference and perpendicular to its plane is given by: I = I_ cm + M d^2 Here, the distance between the parallel axes is d = r . I = M r^2 + M r^2 = 2 M r^2 The radius of gyration k is defined by I = M k^2 . Equating the two expressions for I : M

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