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Required change in pressure to change volume

  1. Mar 12, 2009 #1
    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. jcsd
  3. Mar 12, 2009 #2


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    Homework Helper

    Welcome to PF.

    Why do you feel you are way off?

    Note though that B = ΔP/(ΔV/V)


    They give you already that ΔV/V = .1%
  4. Mar 12, 2009 #3
    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.
  5. Mar 12, 2009 #4


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    Homework Helper

    Reread the problem statement, and my statement again.
  6. Mar 12, 2009 #5
    Sorry that was a stupid mistake. The pressure needed should be 9*10^7. thanks you for your help:smile:
  7. Mar 12, 2009 #6


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    Homework Helper

    Let's be more generous and call it careless.

    As they say:

    Careless happens.
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