The shaft has following Parameters Length of the shaft = 0.7 meters Diameter = 50 mm Applied Torque = 1200 Nm Modulus of rigidity G = 90 GPa a. Calculate the Shear stress and Angle of twist if the shaft is SOLID b. Calculate the Shear stress and Angle of twist if the shaft is HOLLOW with internal diameter of 30mm (6) c. Compare your results and comment on your answer in selection of the correct shaft. d. Explain the term torsional stiffness