How to Calculate Spacing for Bridge Expansion with Linear Expansion Coefficient

[DrMcDreamy]

Homework Statement

A bridge is made with segments of concrete 76 m long (at the original temperature). If the linear expansion coefficient is 1.2 × 10⁻⁵(◦C)⁻¹, how much spacing is needed to allow for expansion for an increase in temperature of 69◦F? Answer in units of cm.

Homework Equations

I don't know, we never did this in lecture, so I lost as to what to do.

The Attempt at a Solution

What formula am I supposed to use?

 

[kuruman]

Homework Statement

A bridge is made with segments of concrete 76 m long (at the original temperature). If the linear expansion coefficient is 1.2 × 10⁻⁵(◦C)⁻¹, how much spacing is needed to allow for expansion for an increase in temperature of 69◦F? Answer in units of cm.

Homework Equations

I don't know, we never did this in lecture, so I lost as to what to do.

The Attempt at a Solution

What formula am I supposed to use?

For a formula check
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thexp.html

 

[DrMcDreamy]

Thank you!

So it would be:

\DeltaL=L_o\alpha\DeltaT

\DeltaL= (76 m)(1.2 x 10^-5)(◦C)^-1(20.5◦C+17.7◦C)

\DeltaL=0.0348 m

 

[DrMcDreamy]

^It came out to be wrong, so what did I do wrong?

 

[kuruman]

Answer in units of cm.

ΔL=0.0348 m

That's what's wrong.

 

[DrMcDreamy]

Oh $h*t! 3.48 cm crap I didnt even realize it had asked in cm!