The shaft is made of A-36 steel. It has a diameter of 42 mm and is supported by bearings at A and D, which allow free rotation. The shear modulus of elasticity for A-36 steel is 75 GPa. B 90 N-m 0.6 m 0.75 m 0.9 m 90 N-m Tap image to zoom Q Part A Determine the angle of twist of gear C with respect to B.