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Homework Help: Heat and internal energy

  1. May 3, 2008 #1
    1. The problem statement, all variables and given/known data
    On his honeymoon, James Joule tested the conversion of mechanical energy into internal energy by measuring temperatures of falling water. If water at the top of a Swiss waterfall has a temperature of 10.0 degrees Celsius and then falls 50.0 m, what maximum temperature at the bottom could Joule expect?

    2. Relevant equations

    change in internal energy = mgh

    3. The attempt at a solution

    I'm sure this question is easy I must be missing something, the change in internal energy is mgh but we have no mass?

    The answer is (10.0 + 0.117) but I don't see how this was found.
  2. jcsd
  3. May 3, 2008 #2


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    Homework Helper

    \Delta E = c M \Delta T
    where c is the specific heat. the mass drops out.
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