Physics - Rotation Question with Solution | TestHub

Hinge is 2L from one end, so the centre of mass is L/2 from the hinge

Moment of inertia about the hinge:

$I=\frac{m(3L{)}^2}{12}+m{\left(\frac{L}{2}\right)}^2=m{L}^2$

Torque of weight about the hinge:

$mg\frac{L}{2}=I\alpha$

$\alpha =\frac{g}{2L}$

Answer: B