Physics - Elasticity Question with Solution | TestHub

A thin uniform elastic rod of natural length ' $\ell$ ', area of cross-section A, density $\rho$ and Young's modulus Y is just completely immersed in vertical position in fluid of density $2\rho$ by applying a vertically downward force (F) at its top end. The rod is in equilibrium. Elastic deformation energy stored in the rod is (Neglect lateral strain in the rod and the atmospheric pressure)