Question

The radius of gyration of a uniform disc about a line perpendicular to the disc equals its radius $R$. The distance of the line from the centre is $\frac{R}{\sqrt{x}}$. Find $x$.

Answer 1

$k=R=\sqrt{\frac{I}{m}}=\sqrt{\frac{\frac{1}{2}m{R}^2+m{d}^2}{m}}$
$\therefore d=\frac{R}{\sqrt{2}}$
Comparing $x=2$