Using the values computed for ${\mathrm{T}}_1$ and ${\mathrm{T}}_2$, calculate the maximum shear stress in each shaft:

$$\begin{gathered} {\mathrm{\tau }}_1=\frac{{\mathrm{T}}_1{\mathrm{c}}_1}{{\mathrm{J}}_1}=\frac{(675.7 \mathrm{N-m})(25 \mathrm{mm})(\mathrm{1,000} \mathrm{mm/m})}{308,102 {\mathrm{mm}}^4} \\ =54,83 \mathrm{MPa} \end{gathered}$$

$$\begin{gathered} {\mathrm{\tau }}_2=\frac{{\mathrm{T}}_2{\mathrm{c}}_2}{{\mathrm{J}}_2}=\frac{(724.3 \mathrm{N-m})(21 \mathrm{mm})(\mathrm{1,000} \mathrm{mm/m})}{225,968 {\mathrm{mm}}^4} \\ =67,31 \mathrm{MPa} \end{gathered}$$