3. At a point P in a body, Cartesian stress components are given by axx = 80 MPa, (Tw, = —40 MPa, crs = —40 MPa, and rjy = TyZ = t0- = 80 MPa. Determine the traction vector, its normal com¬

ponent, and its shear component on a plane that is equally inclined to all three coordinate axes.

Hint: When a plane is equally inclined to all three coordinate axes, the direction cosines of the normal are equal to each other.