Give the following problem a try. If you get stuck, here is one way to work it: Essential Solution Video.

The box beam shown in Figure A has dimensions of $b=80mm,d=125mm,$ and $t=8mm.$ Adownward concentrated load of

$P=43kN$ acts on wall $BC$ of the box at a distance of $a=38mm$ below the $z$ centroidal axis as shown in Figure B$.$ Determine the

normal stress:

$($a$)$ at corner A$.$

$($b$)$ at corner $D.$

FIGURE A

FIGURE B

Your answers below must be consistent with the sign convention for normal stresses.

$($a$){}_{x,A}=$

MPa

$($b$){}_{x,D}=$

MPa