Problem $2(35$ Points$)$

A rectangular bar is cut from an AISI $1020$ cold$-$drawn steel flat. The bar is $2\mathrm{.}5$ in wide by $\backslash (3/8\backslash )$ in$.$ thick and has a $0\mathrm{.}5-$india. hole drilled through the center as depicted. The bar is concentrically loaded in push$-$pull fatigue by axial forces $\backslash (\backslash$mathrm$\{$F$\}=\backslash )4\mathrm{.}2$ kip. Determine the fatigue factor of safety if an infinite life is expected.