A rigid bar $$GH$$ of length $$L$$ is supported by a hinge and a spring of stiffness $$K$$ as shown in the figure below. The buckling load, $${P_{cr}}'$$ for the bar will be

The degree of static indeterminacy of the rigid frame having two internal hinges as shown in the figure below, is

The span$$(s)$$ to be loaded uniformly for maximum positive (upward) reaction at support $$P,$$ as shown in the figure below, is $$(are)$$

The members $$EJ$$ and $$IJ$$ of a steel truss shown in the figure below are subjected to a temperature rise of $${30^ \circ }C.$$ The coefficient of thermal expansion of steel is $$0.000012$$ per $${^ \circ }C.$$ per unit length. The displacement ($$mm$$) of joint $$E$$ relative to joint $$H$$ along the direction $$HE$$ of truss, is