Prob. 2.9-5. A bar with rectangular cross section is subjected to an axial tensile load P, as shown in Fig. P2.9-5. (a) Determine the angle, call it enas of the plane

NN' on which Tnt = 2σn, that is, the plane on which the magnitude of the shear stress is twice the magnitude of the normal stress. (b) Determine the angle, call it Onb, of the plane on which on = 27nt (Hint: You can get approximate answers from Fig. 2.34.) P N N' P2.9-5 (5000)