A $14-$ft$-$long simply supported timber beam carries a $P=12\mathrm{.}0-$kip concentrated load at midspan as shown. The cross$-$sectional

dimensions of the timber are also shown. At section $a-a,$ determine the magnitude of the shear stress in the beam at point $H.$

$89\mathrm{.}1$ psi

$82\mathrm{.}2$ psi

$64\mathrm{.}0$ psi

$60\mathrm{.}3$ psi

$75\mathrm{.}2$