a$)$ in the failure plane $({}_1,{}_2)$ sketch the failure domain for the maximum$-$shear$-$stress $($Tresca$)$ failure

criterion and for the maximum$-$distorsion$-$energy $($Von Mises$)$ failure criterion;

b$)$ in the failure plane $({}_1,{}_2)$ show the point corresponding to each of the following load cases $($Assuming

case I is on the failure boundary$)$

$Cm1$

c$)$ which one of the three load cases above is the "Least Safe" $($i$.$e$.$ it has the lowest load capacity$).$ Explain.