For the $$2D$$ truss with the applied loads shown below, the strain energy in the member $$XY$$ is _______________ $$kN$$-$$m$$. For member $$XY$$, assume $$AE = 30$$ $$kN,$$ where $$A$$ is cross-section area and $$E$$ is the modulus of elasticity.

For the beam shown below, the value of the support moment
$$M$$ is ____________ $$KN$$-$$m$$.

For formation of collapse mechanism in the following figure, the minimum value of $${{P_u}}$$ is $$c{M_P}/L.$$ $${M_P}$$ and $$3{M_P}$$ denote the plastic moment capacities of beam sections as shown in this figure. The value of $$c$$ is ________.

For the beam shown below, the stiffness coefficient $${K_{22}}$$ can be written as