1. $J = \frac{\pi}{2} (0.04)^4 = 1.28(10^{-6})\pi\;m^4$
$\tau_A = \frac{Tc}{J} = \frac{5\times 10^3(0.04)}{1.28(10^{-6})\pi} = 49.7\;MPa$
$\tau_B = \frac{T\rho_B}{J} = \frac{5\times 10^3(0.02)}{1.28(10^{-6})\pi} = 24.9\;MPa$
3. $5.17\;kN\cdot m$
5. $\tau_{máx} = 26.7 MPa$
7. a) 8.35 ksi, b) 5.94 ksi
9. $J = \frac{\pi}{2}(0.03^4)= 0.405(10^{-6})\pi\; m^4$
$\phi_{AC} = -0.00838\;rad = -0.480\degree$