The solid circular aluminium rod has a diameter d=40 mm and can be subjected simultaneously to a torque T in the direction shown and to a tensile axial load P. The modulus of elasticity is E=73 Gpa, and the shear modulus G= 28 Gpa. (a) Determine the shear strain γxy that results if T=1.0kN.m and P=0. (b) For this torsion-only loading, determine the extensional strains εn and εt along the respective n and t directions