Question

The radius of gyration of a uniform rod of length $l$ and mass $M$ about an axis passing through its centre and perpendicular to its length is:

• A. $\frac{l^2}{12}$
• B. $\frac{l}{2\sqrt{3}}$
• C. $\frac{l}{2}$
• D. $\frac{l}{\sqrt{2}}$

Answer 1

The correct option is B $\frac{l}{2\sqrt{3}}$

Radius of gyration =k
$I=\frac{1}{12}m{l}^2$
$\because m{k}^2=I$
$m{k}^2=\frac{1}{12}m{l}^2$
$k=\frac{l}{\sqrt{12}}$
$k=\frac{l}{2\sqrt{3}}$
option (B)