In a two dimensional analysis, the state of stress at a point is shown below.

If $$\sigma = 120\,\,MPa$$ and $${\tau _{xy}} = 70\,\,MPa,\,\,{\sigma _x}$$ and $${\sigma _y},$$ are respectively

The state of two dimensional stresses acting on a concrete lamina consists of a direct tensile stress, $${\sigma _x} = 1.5\,\,N/m{m^2},$$ and shear stress, $$\tau = 1.20\,N/m{m^2},$$ which cause cracking of concrete. Then the tensile strength of the concrete in $$N/m{m^2}$$ is

Which of the following Mohr's circles shown below qualitatively and correctly represents the state of plane stress at a point in a beam above the neutral axis, where it is subjected to combined shear and bending compressive stresses

The magnitude of the only shear stresses acting at a point in plane stress situation is $$7.5\,N/n{m^2}.$$ The magnitudes of the principle stresses will be: