Problem: $2$ A cantilevered round shaft with shoulder filet is to be used for application that involves cyclic loading and temperature of $400C$ such that a life of $500,000$ cycles must be sustained with $99\mathrm{.}9999\%$ reliability. If the shaft is made of AISI $1018$ hot rolled steel with $f=0\mathrm{.}9$ :

What is the maximum completely reversed force $F_x?$

What is the mean stress that can be applied with the stress amplitude resulting from $F_x$ if the fatigue strength $S_f=51k?$

Repeat $(1)$ for a torsional moment $M_x.$