A solid square cross-sectional bar (bxb) with a yield stress of 250 MPa is subjected to a compressive axial force, P = 140 kN acting at the centroid of the section and a torque T = 20 kN.m. This member is to be designed according to maximum shear stress criterion, with a safety factor of 2.
a) What is the minimum allowable cross-sectional dimension, b?
b) What would your answer be if the load was acting parallel to the surface instead of normal to it?