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-   -   Question regarding transfer of heat between two bodies of water. (http://physicshelpforum.com/advanced-thermodynamics/9208-question-regarding-transfer-heat-between-two-bodies-water.html)

 egarci43 Feb 5th 2014 09:46 PM

Question regarding transfer of heat between two bodies of water.

If 500mg of water at -10c is added to another to another body of water 3000mg at 20c what is the final temperature of the 3500mg of water?

I tried this equation
((500 * 10) + (3000 * 20)) / (500+3000) = 18.57

((Va * Ta) + (Vb * Tb)) / (Va+Vb) = Tf

Va = volume in tank A whose temperature is Ta
Vb = volume in tank B whose temperature is Tb
Tf = the temperature of the water after mixing.

Thanks, I am a political "science" major and just enjoy learning about hard science in my spare time.

 clombard1973 Feb 6th 2014 11:16 AM

Hello

Quote:
 Originally Posted by egarci43 (Post 24547) If 500mg of water at -10c is added to another to another body of water 3000mg at 20c what is the final temperature of the 3500mg of water? I tried this equation ((500 * 10) + (3000 * 20)) / (500+3000) = 18.57 ((Va * Ta) + (Vb * Tb)) / (Va+Vb) = Tf Va = volume in tank A whose temperature is Ta Vb = volume in tank B whose temperature is Tb Tf = the temperature of the water after mixing. Thanks, I am a political "science" major and just enjoy learning about hard science in my spare time.
I would say your approach seems reasonable. Although you wrote the temperature of volume A is -10 and yet you used +10 in your calculation. So try using:

((500 * -10) + (3000 * 20)) / (500+3000) = 15.714

I have not checked into the validity of this approach, but intuitively speaking it makes sense to me. Hopes this helps. Craig

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