Question

Older railroad tracks in the U.S. are made of 12-m-long pieces of steel. When the tracks are laid, gaps are left between sections to prevent buckling when the steel termally expands. If a track is laid at 16*C, how large should the gaps be if the track is not to buckle when the temperature is as high as 50*C?

Answer 1

Given that the length of each rail is L = 12.0 m

Initial temperature is Ti = 16^oC

final temperature is Tf = 50^oC

Coefficient of linear expansion of steel is α = 12x10^-6 /^oC

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The change in length of the rail is ΔL = Lα ΔT

                                                        = 12.0m* 12x10^-6 /^oC*(50^oC - 16^oC)

                                                        = 0.004896 m

                                                        = 4.896 mm