Problem 3. A material point has the following stress state with respect to xyz coordinate system [2 1 9= 1 0 -1|MPa [2-1-2] a) Determine the traction vector acting on a plane through that point whose unit normal is n = ) (i+j+k). b) Find the normal and shear stress acting on that plane c) Evaluate the principal stresses and principal directions d) Determine the maximum shear stress acting at that point.