Strain energy stored in a prismatic bar suspended from one end due to its own weight (elastic behaviour) [x = specific weight of material, A = cross-sectional area, L = length of bar]:

• A. \(U = \frac{{{x^2}{A^2}{L^2}}}{{6E}}\)
• B. \(U = \frac{{xA{L^3}}}{{6E}}\)
• C. \(U = \frac{{{x^2}A{L^3}}}{{3E}}\)
• D. \(U = \frac{{{x^2}A{L^3}}}{{6E}}\)