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Homework Help: Rate of vaporisation

  1. Mar 24, 2010 #1
    1. The problem statement, all variables and given/known data

    During exercise the body loses 240 W of heat due to the evaporation of sweat. Assuming that the latent heat of at body temprature is 2255 kJ/kg, determine the rate of vaporisation of sweat.

    answer = 106 mg/s

    2. Relevant equations


    3. The attempt at a solution

    What formula do I need to use here? The only formula I can think of is the one with latent heat and heat energy Q=mL. But this formula only gives mass and doesn't give the rate of vaporisation!
  2. jcsd
  3. Mar 24, 2010 #2


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    Homework Helper

    If 240J is added to the sweat per second and it takes 2255 000 J to vaporize one kg of sweat, how much is vaporized per second? You don't need any formulas, just logic.
  4. Mar 24, 2010 #3
    I'm not quite sure if I understand correctly, do you mean sweat+240J/2255000? :confused:
  5. Mar 24, 2010 #4
    And it is 240 W not Joules...
  6. Mar 24, 2010 #5
    a Watt is just a Joule per second.
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