Given that the same cantilever beam Problem $1$ is under plane strain conditions such

that:

${}_{}=\frac{12P}{b{h}^3}xy$

${}_{yy}=0$

${}_{xy}=(\frac{3P}{2b{h}^3})(h^2-4y^2)$

a$.$ Find the ${}_{33}$

b$.$ Find the corresponding strain field resulting from this stress state.