Para encontrarmos o torque interno, iremos considerar que a estrutura é circular, de raio R:

\(\begin{align} & \tau =\frac{Tc}{J} \\ & \tau =\frac{T\cdot c}{\frac{\pi {{c}^{4}}}{2}} \\ & \tau =\frac{T\cdot R}{\frac{\pi {{R}^{4}}}{2}} \\ & \tau =\frac{2T\cdot R}{\pi {{R}^{4}}} \\ & 200\cdot {{10}^{6}}=\frac{2T}{\pi {{R}^{3}}} \\ & 2T=200\cdot {{10}^{6}}\left( \pi {{R}^{3}} \right) \\ & T=\frac{200\cdot {{10}^{6}}\left( \pi {{R}^{3}} \right)}{2} \\ & T=100\cdot {{10}^{6}}\left( \pi {{R}^{3}} \right) \\ \end{align}\ \)

Portanto,o torque será \(\begin{align} & T=100\cdot {{10}^{6}}\left( \pi {{R}^{3}} \right) \\ \end{align}\ \).