Assignment:
Question 1. A welded railway line, of length 15 km, is laid without expansion joints in a desert where the night and day temperatures differ by 50 K. The cross-sectional area of the rail is 3.6*10^-3 m^2, alpha= 8*10^-6 K^-1, and Y =2*10^11 Nm^-2
(a) What is the difference in the night and day tension in the rail if it is kept at constant length?
(b) If the rail is free to expand, by how much does its length change between night and day?