The steel shaft of a socket wrench has a diameter of 8.0 mm and a length of 200 mm (see figure). If the allowable stress in shear is 60 MPa, what is the maximum permissible torque T max that may be...

The steel shaft of a socket wrench has a diameter of 8.0 mm and a length of 200 mm (see figure).

If the allowable stress in shear is 60 MPa, what is the maximum permissible torque T_max
that may be exerted with the wrench?

Through what angle
 (in degrees) will the shaft twist under the action of the maximum torque? (Assume G = 78 GPa and disregard any bending of the shaft.)