고체역학 (Beer) — Torsion: Problem 3.122

3.122 Determine the smallest allowable length of a stainless steel shaft of \(\frac{3}{8} \times \frac{3}{4}\)-in. cross section if the shearing stress is not to exceed 15 ksi when the shaft is twisted through 15°. Use \(G = 11.2 \times 10^6\) psi.