A hoop of mass 500g and radius 10cm is placed on a nail. Find the moment of inertia of the hoop when it is rotated about the nail----------$kg m^2$

When the hoop is rotated about the nail, the axis of rotation is the tangent perpendicular to its plane. Its moment of inertia

$\mathrm{I}=2{\mathrm{MR}}^2=2\times 0.5\times (0.1{)}^2=0.01\mathrm{kg}{\mathrm{m}}^2$