Question

The kinetic energy of rotating body is $18$ Joule. If the angular momentum vector coincides with the axis of rotation and the moment of inertia of the particle about this axis is $0.01kg{m}^2$, then its angular momentum will be :

• A. $0.06J$-$sec$
• B. $0.6J$-$sec$
• C. $0.006J$-$sec$
• D. Zero

Answer 1

The correct option is B $0.6J$-$sec$

$KE=\frac{L^2}{2I}$
$\Rightarrow 18\times (2\times 0.01)=L^2$
$\Rightarrow L^2=0.36$
$\Rightarrow L=0.6Jsec$