Question: a ductile hotrolled steel bar has a minimum yield strength...

A ductile hot-rolled steel bar has a minimum yield strength in tension and compression of 350 MPa. Using the distortion-energy and maximum-shear-stress theories determine the factors of safety for the following plane stress states: (a) σx = 100 MPa, σy = 50 MPa (b) σx = 100 MPa, τxy = −75 MPa (c) σx = −50 MPa, σy = −75 MPa, τxy = −50 MPa