A stepped shaft ACB is held against rotation at ends A and B and subjected to a torque T0 acting at section C (see figure). The two segments of the shaft (AC and CB) have diameters dA and dB, respectively, and polar moments of inertia IPA and IPB, respectively. The shaft has length L and segment AC has length a.
(a) For what ratio a/L will the maximum shear stresses be the same in both segments of the shaft?
(b) For what ratio a/L will the internal torques be the same in both segments of the shaft? (Use Eqs. 3-45 a and b of Example 3-9 to obtain the reactive torques.)

PA To