The ‘'plane section remains plane’' assumption in bending theory implies:

A symmetric $${\rm I}$$-section (with width of each flange $$=50mm$$, thickness of each flange $$=10mm,$$ depth of web $$=100mm,$$ and thickness of web $$=10mm$$) of steel is subjected to a shear force of $$100$$ $$kN.$$ Find the magnitude of the shear stress (in $$N/m{m^2}$$) in the web at its junction with top flange __________.

The pin-jointed $$2$$-$$D$$ truss is loaded with a horizontal force of $$15$$ ݇ܰ at joint S and another $$15$$ ݇ܰ vertical force at joint $$U,$$ as shown.Find the force in member $$RS$$ (in $$kN$$ ݇ܰ) and report your answer taking tension as positive and compression as negative. _____________

A propped cantilever made of a prismatic steel beam is subjected to a concentrated load $$P$$ at mid span as shown.

If load $$P=80$$ $$kN,$$ find the reaction ܴ$$R$$ (in $$kN$$) (correct to $$1$$-decimal place)using elastic analysis ___________