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Heat and internal energy

  1. Sep 10, 2010 #1
    1. The problem statement, all variables and given/known data
    Water at the top of Niagara Falls has a temperature of 10.0degrees celsius. If it falls a distance of 50.0m and all of its potential energy goes into heating the water, calculate the temperature of the water at the bottom of the falls.

    2. Relevant equations

    W = change in kinetic energy + change in potential energy

    3. The attempt at a solution
    i know there's potential energy on top and none at the bottom. There's not kinetic energy at the top and there is at the bottom. But how do i put temperature into this equation???
  2. jcsd
  3. Sep 10, 2010 #2


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    The change in potential energy of the water = heat absorbed by water

    You should know the equation Q=mcΔT
  4. Sep 10, 2010 #3
    so distance isn't included in the equation? and mass?
  5. Sep 10, 2010 #4


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    The height is a distance and the mass will not really matter.
  6. Sep 11, 2010 #5
    so, mgh = mc(T-Ti)

    then solve for Tf?


    mgh = mc(Tf - Ti)
    gh = cTf - cTi
    gh + cTi = cTf
    gh/c + Ti = Tf
  7. Sep 11, 2010 #6


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    Yes that should work.
  8. Sep 11, 2010 #7
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