If the principal stresses in a plane stress problem are $${\sigma _1}$$ $$= 100$$ MPa, $${\sigma _2}$$ $$= 40$$ MPa, the magnitude of the maximum shear stress (in MPa) wil be

The figure shows the state of stress at a certain point in a stressed body. The magnitudes of normal stresses in the $$x$$ and $$y$$ directions are $$100$$ MPa and $$20$$ MPa respectively. The radius of Mohr's stress circle representing this state of stress is

If the two principal strains at a point are 1000 $$ \times $$ 10^-6 and -600 $$ \times $$ 10^-6, then the maximum shear strain is

A cylindrical elastic body subjected to pure torsion about its axis develops: