The moment diagram for the same loaded box beam from Problem $1$ is provided below.

$I_{NA}=5\mathrm{.}0(10{)}^{7}m{m}^4$

$M_{\text{m}\text{a}\text{x}}=$

${}_{\text{m}\text{a}\text{x}}=$

${}_p=$

B$)$ At the $x$ location of maximum internal bending moment, calculate:

I. The magnitude of the maximum internal moment due to bending

II$.$ The maximum bending stress in the beam

III. The normal stress due to bending at $P(10mm$ down from the top of the beam$)$

${}_{\text{m}\text{a}\text{x}}=|\frac{M*c}{l}|,{}_p=\frac{-M*y_p}{l}$