고체역학 (Beer) — Principal Stresses Under a Given Loading: Problem 8.59

8.59 A force P is applied to a cantilever beam by means of a cable attached to a bolt located at the center of the free end of the beam. Knowing that P acts in a direction perpendicular to the longitudinal axis of the beam, determine (a) the normal stress at point a in terms of P, b, h, l, and \(\beta\), (b) the values of \(\beta\) for which the normal stress at a is zero.