A25 mm diameter solid round bar has a groove 2.5 mm deep with a 2.5 mm radius machined into it. the bar is made of aisi 1030 cd steel and is subject to purely reversing bending of 220 n. m. for the s-n curve of this material, let the fatigue strength fraction be equal to 0.9. (a) estimate the number of cycles to failure (b) what is the factor of safety guarding against static failure? (c) if the bar is also placed in an environment with a temperature of 350 oc, estimate the number of cycles to failure