4) A critical point in a machine part is subjected to a steady load that gives rise to a triaxial state of stress of the form 200 100 130 100 300 60 130 60 4.00 The material for the part has a yield point stress of 800 MPa. a) Determine the principle normal stresses b) Will the part fail by the max. Shear stress theory of failure if Nfs-2?