# Homework Help: Work done through linear expansion

1. Dec 12, 2012

### LadyMario

An 8000kg aluminum flagpole 100m long is heated by the sun from a temperature of 10°C to 20°C. Find the work done (in J) by the aluminum if the linear expansion coefficient is 24*10-6 /°C. (The density of aluminum is 2.7*103 kg/m3 and 1 atm = 1.0*105 N/m2)

I know w=PΔV, and I know V at 10°C = mass/density= 8000/2.7*103 = 2.963m3

I know how much longer the flagpole grows: ΔL=αLΔT = 24*10-6(100)(20-10)=0.024m

But how does the volume at 20°C relate to the growth of the flagpole through linear expansion?

The answer is suppsoed to be 213 J.

2. Dec 12, 2012

### TSny

Do you know the formula for volume expansion? The coefficient of volume expansion has a simple relation to the coefficient of linear expansion.

3. Dec 12, 2012

### LadyMario

Yea I found it in the textbook. We were never taught it in class, so I was trying to find another way to do it, but oh well :P

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