$4$

$\frac{0}{1}$ point

A rectangular bar of dimensions $b$hmm is subjected to a combined bending load as shown. For $b=12mm,h=25mm,$ and $My=103Nm,Mz=74Nm,$ determine the bending stress at point D$.[$Mpa$]($sign sensitive: positive for tensile stress, negative for compressive stress$)$