= A stepped shaft has shown below. The region AB is aluminium, having G 28 GPa, and the region BC is steel, having G = 84 GPa. The aluminium portion is of solid circular cross section 45 mm in diameter, and the steel region is circular with 60 mm outside diameter and 30 mm inside diameter. Determine the maximum shearing stress in each material well as the angle of twist at B where a torsional load of 4 kN-m is applied. clamped. Ends A and C are as rigidly A TL 45 mm 1.2 m B 60 mm 30 mm 2 m 4000 N-m 2 m 1.2 m- TR