given a uniform diameter shaft made of steel with an ultimate strength of 79 kpsi, a yield strength of 44 kpsi, and a fully corrected endurance limit of 22 kpsi, what is the minimum diameter of the shaft needed to ensure the shaft will not yield and will have infinite life given a fully reversed bending moment of 659 in-lbs and a steady torsional load of 1,860 in-lbs? use a design factor of 1.4, assume there are no stress concentrations, and use the goodman failure criterion if needed.