Fatigue strength of a rod subjected to cyclic axial force is less than that of a rotating beam of the same dimensions subjected to steady lateral force. What is the reason?
(a) Axial stiffness is less than bending stiffness
(b) Absence of centrifugal effects in the rod
(c) The number of discontinuities vulnerable to fatigue is more in the rod
(d) At a particular time, the rod has only one type of stress whereas the beam has both tensile and compressive stresses