question_answer

A bar of length L and of uniform cross-section are A and second moment of area l is subjected to a pull P. If Young's modulus of elasticity of the bar material is E, the expression for strain energy stored in the bar will be

A) \[\frac{{{P}^{2}}L}{2AE}\]                

B) \[\frac{P{{L}^{2}}}{2EI}\]

C) \[\frac{P{{L}^{2}}}{AE}\]                              

D) \[\frac{{{P}^{2}}L}{AE}\]