PLS EXPLA$$N $$N DETA$$LS Problem $3$: $(25$ points$)$ The composite beam is made of steel $($A$)$ bonded to brass $($B$)$ and has the cross$-$section shown below. If it is subjected to a moment of $M_z=10kNm,$ determine the maximum bending stress in the brass and steel. $)=100$GPa,$E_{st}=(200$GPa

Hint: Use transformed section method

If material $1$ is transformed into material $2,$

$n=\frac{E_1}{E_2}$ and $=n{}^{\text{'}}$ where;

${}^{\text{'}}=$ Stress in material $2$

$=$ True stress in the transformed material