고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.61

2.61 In a standard tensile test, a steel rod of \(\frac{7}{8}\)-in. diameter is subjected to a tension force of 17 kips. Knowing that \(\nu = 0.30\) and \(E = 29 \times 10^6\) psi, determine (a) the elongation of the rod in an 8-in. gage length, (b) the change in diameter of the rod.