고체역학 (Beer) — Torsion: Problem 3.41

3.41 Two shafts, each of $\frac{7}{8}$-in. diameter, are connected by the gears shown. Knowing that $G = 11.2 \times 10^6$ psi and that the shaft at $F$ is fixed, determine the angle through which end $A$ rotates when a 1.2-kip·in. torque is applied at $A$.