고체역학 (Beer) — Torsion: Problem 3.136

3.136 A 3000-lb⋅in. torque is applied to a 6-ft-long steel angle with an L4 × 4 × 3/8 cross section. From Appendix E we find that the thickness of the section is 3/8 in. and that its area is 2.86 in². Knowing that G = 11.2 × 10⁶ psi, determine (a) the maximum shearing stress along line a-a, (b) the angle of twist.