A steel stepped shaft ABCD fixed at A is subjected to three torques at points B, C and D, with magnitudes T, 40 kip-in, T-50 kip-in and Ts-30 kip-in and directions as shown in Figure 1.1. The segments AB and BC are solid with diameters daa-3 in and dec 2 in respectively, while segment CD is hollow with an outer diameter dcon1.5 In and a wall thickness of 0.25 in. The shear modulus of elasticity is equal to G 11.6x10' ksl. T Hollow T C 4-20 in 4-25 in Figure 1.1 a) Draw the torsion moment diagram for the shaft and calculate how long should segment CD be so that the angle of twist between points B and D is equal to zero. b) If Ts is dropped, a fixed support is added at point D (as shown in Figure 1.2) and the length of segment CD is equal to 15 in, find the support reactions at points A and D and the maximum shear stress developed in segment BC. The magnitudes of the torques at points B and C are the same as in part a). Hollow T 4-20 in 4-25in L-15 in