$14\mathrm{.}12$ The timber box section $($a$)$ of Problem $14\mathrm{.}29$ is used as a

simply supponted beam on an $18-$ft span length. The beam

carries a uniformly distrihuted load of $500$l$($t$)/($f$)$t$,$ which in$-$

cludes its own weight. Calculate the maximum induced bending stress.

$14\mathrm{.}29$ Calculate the maximum horizontal shear stress if the mem$-$

ber is subjected to a maximum vertical shear of $4500lb.$

For the I$-$shaped timber beam shown, calculate the maxi$-$

mum vertical shear force that will induce a maximum hori$-$

zontal shear stress of $120.$ Then calculate the shear stress

in the plane of the junction between the web and the flange.

need help with question $14\mathrm{.}12$