Answer:
ΔL = 1.2 10⁻³ m
Explanation:
The expression for thermal expansion is
ΔL = α L₀ ΔT
in this case it indicates that the length is L₀ = 5 m for T₀ = 20C the final temperature is T_f = 40 C
the table shows the value of thermal expansion for steel α = 12 10⁻⁶ C⁻¹
let's calculate
ΔL = 12 10⁻⁶ 5 (40 -20)
ΔL = 1.2 10⁻³ m
