# Homework Help: Linear Expansion equations

1. Apr 2, 2015

### Patricia Reid

1. The problem statement, all variables and given/known data
An object has a density of 1250 kg /m3 at 10C and a coefficient of linear expansion of α = 2.5 × 10−5 1 /K . What is the object’s density when the temperature is 25C?

2. Relevant equations
V=βV0ΔT
V(T)=(1+β(Δt))V0

3. The attempt at a solution
How I got the answer is that I used V(T)=(1+β(Δt))V0 and substituted v=m/ρ and after some algebra gave me the correct answer of 1248.6 kg/m2

When I used the first equation I listed I didn't get the correct answer... I was just wondering what the difference is in the equations and when to use them

Thanks in advance!

2. Apr 2, 2015

### Orodruin

Staff Emeritus
The first equation is not for the volume, it is for the change of volume. You can see this by inserting zero temperature difference (you will get zero and not the volume).

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