



 
Hi Ken, The formulae for linear and area thermal expansion are as follows:
where α is the thermal coefficient for a material, ΛT is change in temperature, ΛL is change in length, ΛA is change in area, L_{o} is the initial length and A_{o} is the initial area. Similarly change in volume would be ΛV/V_{o}=3αΛT The thermal coefficient for steel is 13.0 ×10^{6} m/m K. You have to make sure all of your units are the same and a change of 40F is about 4.4K. You can just plug in all of values and solve for ΛL, ΛA or ΛV to find thermal expansion. Hope this helps, Janice  


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