$17\mathrm{.}1$ A $100-$mm$-$by$-100-$mm $($S$4$S$)$ timber beam on a simple span of $4$ m is subjected to vertical and lateral point loads placed at midspan, as shown. The lines of action of the loads pass through the centroid of the cross section. Determine the stresses at the corners of the cross section at the point of maximum moment.

Please show work

$($Book Answer: $5\mathrm{.}55$MPa, $2\mathrm{.}13$MPa$)$