Suppose a solid round shaft of diameter 30 mm is designed at rotating speed of 300 rpm, and made of steel (su =400 mpa, sy =200 mpa). currently it is subject to a fluctuating torque mainly during operation. a) what is the fatigue strength at 103 and 106 cycles? (assume reversed cycles, maximum temperature at 100 c, machined surface finish, and reliability factor equals to 1). (b) what is the maximum stress allowed if this workpiece can stay in operation for 105 cycles without fatigue failure? to find the exact value and use graph method to verify it. ) the workpiece is actually loaded with a fluctuating zero to maximum torque, draw a goodman diagram, and use the ratio (shear stress (m)/shear stress (a)) to estimate the corresponding maximum stress of safety factor 3 applied to this workpiece with respect to 105 cycle fatigue life. (d) with the stress determined in (c), what is corresponding maximum torque allowed.