2. Consider the following stress state 1- - 0 0 00 00 1]... where do is some stress value and a is a dimensionless parameter a (0, 1). (a) Calculate the principal invariants of the stress tensor: I = tro, I2 = (tr[(0) - (tro)], 13 = det . (b) Determine the deviatoric stress tensor s. (c) Determine the deviatoric invariants J2 ja J3 and the Lode angle and draw the position of the stress on the deviatoric plane as a function of the parameter a. (d) Determine traction vector t on a plane whose normal points in direction (1,2,2)T. Determine also the normal stress and shear stress (and its direction) on this plane. (e) Determine the principal stresses and the principal directions. (f) Determine the principal values of the deviatoric stress tensor.