The steel rails of a railroad track (Es = 200 GPa, as =

QUESTION:

The steel rails of a railroad track \(\left(E_{s}=200 \mathrm{GPa}, \alpha_{s}=11.7 \times 10^{-6} /{ }^{\circ} \mathrm{C}\right)\) were laid at a temperature of \(6^{\circ} \mathrm{C}\). Determine the normal stress in the rails when the temperature reaches \(48^{\circ} \mathrm{C}\), assuming that the rails (a) are welded to form a continuous track, (b) are 10 m long with 3-mm gaps between them.