A pipe with closed ends has a wall thickness of 10 mm and an inner diameter of 0.6 m. It is filled with gas at 20 MPa pressure and is subjected to a torque about its long axis of 1200 KNm. (a) Determine the three principal stresses and the maximum shear stress, (b) Determine its fracture angle if the material is brittle and fracture occurs, (c) Determine its fracture angle if the material is ductile and fracture occurs, Neglect any discontinuity associated with the end closure.