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

:$.2-10.$ A cubc of metal, baving a yield strength $Y$ of $345$ MPa $,$ is subjected to two per pendicular normal stresses, ${}_1$ and ${}_3=-\frac{{}_1}{2},$

a$,-5($a$)$ Find the ratro of $dlo\frac{n_1}{d}lo{n}_2.-\frac{1}{2}$ sensilestress$.$

$($b$)$ What is ${}_{\text{m}\text{e}\text{x}}$ at the onset of yielding using the von Mises criterion?