Now that the stress in wire $\left(1\right)$ is known, the force in the wire can be determined:

$$\begin{gathered} {\mathrm{F}}_1={\mathrm{\sigma }}_1{\mathrm{A}}_1=(160 \mathrm{N}/{\mathrm{mm}}^2)(2 {\mathrm{mm}}^2) \\ =320 \mathrm{N} \end{gathered}$$