고체역학 (Beer) — Stress and Strain—Axial Loading: Problem 2.2

2.2 A control rod made of yellow brass must not stretch more than 1/8 in. when the tension in the wire is 800 lb. Knowing that \(E = 15 \times 10^6\) psi and that the maximum allowable normal stress is 32 ksi, determine (a) the smallest diameter rod that should be used, (b) the corresponding maximum length of the rod.