The solid shaft of radius r = 0.5 inches and shear modulus G = 10,000ksi is subjected to the torques shown, and T = 10,000lb - in. At the surface of the shaft, the angle between the "line before torques are applied" and the same line "after torques are applied" is shown in the figure. (a) Find the magnitude of that angle; (b) If the length of the shaft is 48 inches, find the relative rotation between the left and the right end of the shaft.

T Line before torques are applied Line after torques are applied T