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Solids Elasticity (Bulk Modulus)

  1. May 5, 2009 #1
    1. The problem statement, all variables and given/known data
    When the water freezes it expands by about 9.00%. What pressure increase would occur inside your automobile engine block if the water in it froze?(The bulk modulus of ice is 2.00 x 10^9 N/m^2).

    2. Relevant equations
    [tex]B=\frac{\Delta P}{\Delta V / V_i}[/tex]

    3. The attempt at a solution
    If I solve the problem "forward in time" I get this:
    [tex]\Delta P=\frac{1.09V_i-Vi}{Vi}B=0.09B[/tex]

    but if solving the problem "backwards in time"

    [tex] \Delta P = \frac{V_i-1.09V_i}{1.09V_i}B = 0.0826B [/tex]

    Shouldn't both answers have the same magnitude?
    Last edited: May 5, 2009
  2. jcsd
  3. May 5, 2009 #2


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    No; 90% of 110% of x is not x, for example.
  4. May 5, 2009 #3
    Of Course. Thanks
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