At what temperature would the wing be 2 cm (0.02 m) shorter?

Question

An aluminum wing on a passenger jet is 28 m

long when its temperature is 15°C

At what temperature would the wing be 2 cm (0.02 m) shorter?

Answer 1

The linear thermal expansion coefficient of aluminum and its common alloys is around 24×10^-6 per °C. Therefore a 2 cm length change over 28 m is 0.02/28 = 7.14×10^-4 relative length change. Thus correspond temperature change is 7.14×10^-4 / 24×10^-6 = 29.8 °C. If the length is getting shorter, the temperature should be lower, therefore the answer is 15-29.8 = -14.8 °C.