Beer & Johnston — Torsion: Problem 3.83

3.83 A 1.5-m-long tubular steel shaft of 38-mm outer diameter \(d_1\) is to be made of a steel for which \(\tau_{\text{all}} = 65 \text{ MPa}\) and \(G = 77.2 \text{ GPa}\). Knowing that the angle of twist must not exceed \(4^\circ\) when the shaft is subjected to a torque of \(600 \text{ N}\cdot\text{m}\), determine the largest inner diameter \(d_2\) that can be specified in the design.