Question

The radius of gyration of a rotating metallic disc is independent of which of the following physical quantity.

• A. Position of axis of rotation
• B. Mass of disc
• C. Radius of disc
• D. Centre of mass of disc

Answer 1

The correct option is B Mass of disc

$I=m{k}^2$
$k=\sqrt{\frac{T}{m}}$
$I=\frac{m{R}^2}{2}$
$k=\frac{R}{\sqrt{2}}$
$\therefore r=R_0(1+\alpha \Delta T)$
$\therefore$ k is independent of mass.