고체역학 (Beer) — Torsion: Problem 3.26

3.26 The two solid shafts are connected by gears as shown and are made of a steel for which the allowable shearing stress is 8500 psi. Knowing that a torque of magnitude \(T_C = 5 \text{ kip}\cdot\text{in.}\) is applied at \(C\) and that the assembly is in equilibrium, determine the required diameter of (a) shaft \(BC\), (b) shaft \(EF\).