Physics - Rotation Question with Solution | TestHub

A uniform rod$\mathrm{AB}$of mass$2 \mathrm{kg}$and length$1 \mathrm{m}$is placed on a sharp support$\mathrm{O}$, such that$\mathrm{AO}=a=25 \mathrm{cm}$and$\mathrm{OB}=b=75 \mathrm{cm}$. A spring of force constant$600 \mathrm{N} {\mathrm{m}}^{-1}$is attached to the end$\mathrm{B}$, as shown. Initially, the spring is extended by$2 \mathrm{cm}$at equilibrium. As soon as the thread is burnt, find the normal force (in$\mathrm{N}$) exerted by the support at$\mathrm{O}$.