Need some direction please. Thermodynamics.

[travism123]

Homework Statement

Aluminum wing is 30m long at 20*c

At what temperature would the wing be .05m shorter?

The coefficient for linear expansion of aluminum is (16 x 10^-6/c)


I have no idea how to do this. I don't want an answer. Just an equation or a hint on what to do. Thank you very much.

 

[rl.bhat]

What is the relation between the initial length , final length , coefficient of linear expansion and temperature difference?

 

[travism123]

I have no idea.

 

[HallsofIvy]

Where did you get that coefficient? "16 x 10^-6/c" Are you sure of the "units"? What does "/c" mean? You might want to check that.

 

[travism123]

Sorry,
I messed up the coefficient. It's 25 x 10^-6/*C

 

[travism123]

I'm sorry if I sound stupid not being able to figure this question out. The truth is I probably have no business being in a physics class. I'm going to school to be a therapist and am taking this class to fill a science requirement. I'm sure there are easier classes I could've taken, but a few months before the semester started I saw that documentary The Elegant Universe and thought hmm... physics looks fun. That blasted Brian Greene and his easy to understand explanations!

 

[travism123]

Does this look right?

Aluminum wing is 30m at 20*C. At what temp would it be .05m shorter.
∆T = ∆l / α x l
∆T = -.05m/(25 x 10-6/*C) x 30m
∆T = -66.667
The wing would be at -46.667*C to be .05m shorter.

 

[rl.bhat]

Yes.

 

[travism123]

Thank you very much.