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MHT CET 2023 (9 May, Shift 1) · Moment of Inertia & Radius of Gyration

Moment of Inertia & Radius of Gyration question from MHT CET 2023 (9 May, Shift 1)

Q96MHT CET 2023 · 9 MAY · SHIFT 1Medium

Moment of Inertia & Radius of Gyration

A square lamina of side 'bb' has same mass as a disc of radius 'RR' the moment of inertia of the two objects about an axis perpendicular to the plane and passing through the centre is equal. The ratio bR\frac{b}{R} is

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Answer: (b)

  1. Square lamina about the perpendicular axis through centre: I=Mb26I = \frac{Mb^2}{6}.
  2. Disc: I=MR22I = \frac{MR^2}{2}.
  3. b26=R22⇒b2=3R2\frac{b^2}{6} = \frac{R^2}{2} \Rightarrow b^2 = 3R^2
  4. So the answer is (b) 3:1\sqrt{3} : 1.
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