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## Homework Statement

The 2000 mm long composite bar shown in Fig. 1 consists of an aluminum bar having

a modulus of elasticity EAl = 70 GPa and length LAl = 500 mm, which is securely fastened

to a steel bar having modulus of elasticity ESt = 210 GPa and length LSt = 1500 mm. After

the force P is applied, a tensile normal strain of εAl = 1000 × 10-6 is measured in the

aluminum bar. Find the tensile normal stress in each bar and the total elongation of the

composite bar.

## Homework Equations

ε_x=σ_x/E

## The Attempt at a Solution

So I first took the equation and rearranged it, such that ε_x*E=σ_x and got σ_AL=0.07 GPa. Then for the changed in distance of the aluminum bar, dl=ε*l_0 = (1000*10^-6)(500mm) = 0.5mm change for Al bar.

Assuming that's correct, I'm stuck on how to find the stress for the steel bar and the length it changed.