Question

The moment of inertia of a meter scale of mass $0.6kg$ about an axis perpendicular to the scale and located at the $20cm$ position on the scale in $kg{m}^2$ is :

• A. $0.074$
• B. $0.104$
• C. $0.148$
• D. $0.208$

Answer 1

The correct option is B $0.104$

Moment of Inertia of the scale around the center of mass is

$I_{cm}=\frac{M{L}^2}{12}$

Moment of inertia of the scale around an axis at a distance of 'x' from the CM axis is

$I=I_{cm}+M{x}^2$

$x=(50-20)$ $cm$

$I=\frac{M{L}^2}{12}+M{x}^2$

$I=0.6(\frac{{100}^2}{12}+{30}^2)kgc{m}^2$

$=1040kgc{m}^2$ $=0.104kg{m}^2$