## Solution to Problem 261 Thermal Stress

**Problem 261**

A steel rod with a cross-sectional area of 0.25 in^{2} is stretched between two fixed points. The tensile load at 70°F is 1200 lb. What will be the stress at 0°F? At what temperature will the stress be zero? Assume α = 6.5 × 10^{-6} in/(in·°F) and E = 29 × 10^{6} psi.