The strain energy stored in a body of volume V, when the load is gradually applied, is (σ : stress and E : Modulus of elasticity):

The slope at the support end of a simply supported beam of length 'l' subjected to a uniformly distributed load 'w' throughout its length is equal to (where flexural rigidity EI is constant):

Under which of the following conditions is an element subjected to stresses said to be in a state of triaxial stress?