1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Thermal energy to be dissipated in an hour

  1. Mar 25, 2012 #1
    1. The problem statement, all variables and given/known data

    During the game, the metabolism of basketball players often increases by as much as 30.0 W. How much perspiration must a player vaporize per hour to dissipate this extra thermal energy? Assume that perspiration is simply pure water and that perspiration starts at temperature of 37 degrees celcius.

    2. Relevant equations


    3. The attempt at a solution

    Thermal energy to be dissipated in 1.00h is

    The amount of water this energy transmittes as heat would vaporize is,
    m=(1.08x10^5J)/(2.26X10^6J/kg)= 4.78x10^-2kg

    ----> Just looking for someone to double check my reasoning/calculations and to make sure the number of significant figures has been respected. Thank you so much in advance!
  2. jcsd
  3. Mar 25, 2012 #2


    User Avatar

    Staff: Mentor

    You don't seem to have taken into account the starting temperature of the perspiration.
  4. Mar 25, 2012 #3
    your calculation for the energy needed to vaporize that amount of water is correct.
  5. Mar 25, 2012 #4


    User Avatar

    Staff: Mentor

    Hmm. The heat of vaporization for water varies with temperature. At the boiling point (100C) it's 2.257 x 106 J/kg, but at 37C it's more like 2.40 x 106 J/kg.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Thermal energy to be dissipated in an hour
  1. Energy is dissipated (Replies: 2)