As seen in Fig. P3.40, a stepped shaft ABC with built-in end at A carries the torques TB...

As seen in Fig. P3.40, a stepped shaft ABC with built-in end at A carries the torques T_B and T_C sections B and C. Based on a stress concentration factor K = 1.6, determine the maximum shearing stress in the shaft. Given: d₁ = 50 mm, d₂ = 40 mm, T_B = 3 kN m, and T_C = 1 kN m.