A steel shaft and an aluminum tube are connected by a rigid disc. One end is fixed as shown in the figure, and the allowable The shear stress (ta) is 120MPa for steel and 80MPa for aluminum. If there is stress in the original state, find (a) The maximum permissible torque T acting on the rigid disc (b) If the mold loads of the steel and the pavilion are G=120GPa and G=60GPa respectively, find the maximum allowable force The torsion angle of a rigid disk under the action of moment 76 mm 8 mm 50 mm -500 mm