# Required change in pressure to change volume

1. Mar 12, 2009

### ryan.howie

1. The problem statement, all variables and given/known data

How much pressure is needed to compress the volume of an iron block by 0.10%?

2. Relevant equations

the bulk modulus of iron= 9*10^10
delta_P= B*Vo/delta_V

3. The attempt at a solution
I have tried using random volume for example 1 and 0.01, and 2 and 0.02 but i feel i am way off.

2. Mar 12, 2009

### LowlyPion

Welcome to PF.

Why do you feel you are way off?

Note though that B = ΔP/(ΔV/V)

http://hyperphysics.phy-astr.gsu.edu/hbase/permot3.html#c1

They give you already that ΔV/V = .1%

3. Mar 12, 2009

### ryan.howie

Thanks for the welcome and quick reply,

so ΔP=B(ΔV/V)
and B=9*10^10
and as you said ΔV/V=1%
so the change in pressure should be 1% of B which 9*10^8 N/m^2
but this is one of my previous answers and is wrong.

4. Mar 12, 2009

### LowlyPion

Reread the problem statement, and my statement again.

5. Mar 12, 2009

### ryan.howie

Sorry that was a stupid mistake. The pressure needed should be 9*10^7. thanks you for your help

6. Mar 12, 2009

### LowlyPion

Let's be more generous and call it careless.

As they say:

Careless happens.