If the compressive axial load in Case 4 of the example problem in Section 8.4.4 were to be replaced by a tensile axial load, suggest possible orientations of
(a) planes of maximum shear strain amplitude,
(b) planes of maximum normal stress amplitude,
(c) planes on which stage I shear cracks may form and
(d) planes on which tensile cracks may form, and
(e) the expected relative fatigue life.