On a very hot day, I saw a 1.6 meter long steel bar held between two rigid supports that had buckled due to the heat. The bar had a cross section of 10 mm by 40 mm, and I assume was A36 steel.
a. What force was needed to buckle it?
b. Assuming the bar was installed without stresses on a 20 C degree day, how hot was it when the bar buckled?