The moment of inertia of a uniform circular disc of radius $R$ and mass $M$ about an axis touching the disc…

The moment of inertia of a uniform circular disc of radius $R$ and mass $M$ about an axis touching the disc at its diameter and normal to the disc:
  1. $\frac{1}{2} M R^2$
  2. $M R^2$
  3. $\frac{2}{5} M R^2$
  4. $\frac{3}{2} M R^2$

Solution

M. I. of uniform circular disc about an axis and perpendicular to the plane is: $I_C=\frac{1}{2} M R^2$ Using the theorem of parallel axis. M. I. of uniform circular disc about an axis touching the disc at it diameter is: $\begin{aligned} I & =I_C+M R^2 \\ & =\frac{1}{2} M R^2+M R^2 \\ & =\frac{3}{2} M R^2 . \end{aligned}$ .

Asked in: NEET 2006

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