A three hinged parabolic arch $$ABC$$ has a span of $$20$$ $$m$$ and a central rise of $$4$$ $$m.$$ The arch has hinges at the ends and at the center. A train of two point loads of $$20$$ $$kN$$ and $$10$$ $$kN$$, $$5$$ $$m$$ apart, crosses this arch from left to right, with $$20$$ $$kN$$ load leading. The maximum thrust induced at the supports is

The unit load method used in Structural analysis is

For a linear elastic structural system, minimization of potential energy yields

The plane frame below is analyzed by neglecting axial deformations. Following statements are made with respect to the analysis :

$$1.$$$$\,\,\,\,\,\,\,$$ Column $$AB$$ carries axial force only.
$$2.$$$$\,\,\,\,\,\,\,$$ Vertical deflection at the center of beam $$BC$$ is $$1mm.$$

Which of the following applies?