$4$

$0/1$ point

The elbow member shown is fixed on one end and subjected to the force $P.$

The member is constructed from an aluminum plate having a thickness of $0\mathrm{.}75$ in $.$

If the resultant internal loads on the cross section of point $D$ are:

$N=16\mathrm{.}9$kip $($tension$),$

$V=10\mathrm{.}8$kip $($counterclockwise$),$

$M=144$ kip$-$in $($leftward$),$

determine the resulting stress component ${}_x$ at point D $.[$ksi$]($sign sensitive: positive for tensile stress, negative for compressive stress$)$