We are designing a part from ductile steel. the part, which has a rectangular cross section of 2 inches tall by 4 inches wide, will be used in a highly polished condition and will only be subjected to bending (non-rotating) fatigue stresses. we would like to design for a reliability of 95% and use this part at 200ºf. a moore specimen made from this material was found to have a fatigue strength of sf’ = 60 ksi. what fatigue stress do we need to stay below if we want our part to last for at least 3 x 106 cycles?