A 20-mm diameter rod made of a ductile material with a yield strength of 350 MPa is subjected to torque of 100 N.m and a bending moment of 150 N.m. An axial force is then gradually applied. Determine the value of force when the rod begins to yield. Solve the problem two ways using the (a) Tresca theory (Maximum shearing stress theory) and (b) von Mises theory (Maximum distortion energy theory).