# Temperature Problem of steel rod

1. Jan 16, 2006

### atelaphobia

Thermal Expansion Problem

i posted this thread in another forum because i really dont know where this question would apply but here goes
i've been working on this problem forever and i dont know what i'm doing wrong!
a steel rod undergoes a stretching force of 500 N. Its cross sectional area is 2.00 cm^2. Find the change in temperature that would elongate the rod by the same amount as the 500-N force does.
here's some info that may be of some use but i dont know how to use it!
average linear expansion coefficient: 11x10^(-6)
young's modulus: 20x10^10
shear modulus: 8.4x10^10

Last edited: Jan 16, 2006
2. Jan 16, 2006

### Pyrrhus

Well assuming the material is elastic linear, you can apply Hooke's Law for uniaxial stress and find the displacement, then with the displacement found, you could equal it with the linear expansion equation for heat, and solve for the temperature difference (change in temperature). Btw, wrong forum, this is introductory physics.

3. Jan 16, 2006

### HallsofIvy

Staff Emeritus
"Young's modulus" measures how much a solid stretches in response to a force (basically the Hook's law coefficient).
"Shear modulus" measures how much the cross section of a solid contracts in response to a stretching of the length.
"Linear expansion coefficient" measures how much a solid will expand (in length) in response to a temperature change.

No, I didn't happen to know that off hand. I looked them up, right now, on "google.com".

Use Young's modulus to determine how much the material will stretch in response to a 500 N force. Use the linear expansion coefficient to determine the temperature necessary to produce that expansion.

4. Jan 16, 2006

### atelaphobia

like i said.. i didnt know where to put this question... i saw clac and beyond and figured it would be a good place to put it...so my apologies..

i figured out the problem last night right after i posted it!

F/A=Y*coefficient of linear expansion*change in temp and solved for temp

thanks you guys!