Each bar has a 500‐mm 2 cross-sectional area, modulus of elasticity E = 72 GPa, and coefficient of thermal expansion α = 25E‐6 o C -1 . The normal stresses in the bars are initially zero. If their...

Each bar has a 500‐mm²
cross-sectional area, modulus of elasticity
E
= 72 GPa, and coefficient of thermal expansion
α
= 25E‐6^oC^-1. The normal stresses in the bars are initially zero. If their temperature is increased by 20^oC and a 15-kN downward force is applied at
A, what are the normal stresses in the bars?