Question

A steel wire of length 4.7 m and cross-section 3 x 10^–5 m² stretches by the same amount as a copper wire of length 3.5 m and cross-section 4 x 10^–5 m² under a given load. What is the ratio of the Young's modulus of steel to that of copper?

Answer 1

For steel wire, A₁ = 3 x 10^-5 m², l₁ = 4.7 m;

For copper wire, A₂ = 4 x 10^–5 m² , l₂ = 3.5 m

As ∆l₁ = ∆l and F₁ = F₂ = F