A railway track (made of iron) is **** in winter when the average temperature is 18°C. The track consists of sections of 12.0 m placed one after the other. How much gap should be left between two such sections so that there is no compression during summer when the maximum temperature goes to 48°C ? Coefficient of linear expansion of iron = 11 x 10 -6/°C.
L0 = 12 cm, α = 11 × 10–5 /°C tw = 18°C ts = 48°C Lw = L0(1 + αtw) = 12 (1 + 11 × 10–5 × 18) = 12.002376 m Ls = L0 (1 + αts) = 12 (1 + 11 × 10–5 × 48) = 12.006336 m ΔL=12.006336 – 12.002376 = 0.00396 m ≅ 0.4cm
