December 22, 2024, 04:57:27 PM
Forum Rules: Read This Before Posting


Topic: calculating energy requirements  (Read 3554 times)

0 Members and 1 Guest are viewing this topic.

Offline ericbmd

  • Regular Member
  • ***
  • Posts: 14
  • Mole Snacks: +0/-1
calculating energy requirements
« on: May 27, 2006, 12:41:21 PM »
A 175lb  man was placed in a tank filled with 1000 gallons of water.  The temperature of the water increased by 2.49 degrees C. over a 1.50 hr period.  calculate the heat lost by the man during this experiment.   Using that data, calculate the energy required over a 24 hr. period.

I know that Heat(cal)= Mass(g) x temp change in degrees C.   x specific heat (cal/g x degree c)
the change in temp is 2.49 degrees C. and the specific heat of water is 1.00 I just dont know where to go from there and how to set it up.  How is energy calculated???




Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: calculating energy requirements
« Reply #1 on: May 27, 2006, 03:19:45 PM »
Alright, so you know the temp change and you know the specific heat of water.  Now to calculate the heat all you need is mass.  Mass here refers to the mass of water since you're calculating the heat gained by the water.  Note that because of the conservation of energy, the heat gained by the water must equal the heat lost by the man.

So, you are given the volume of water.  Given that the density of water is about 1g/mL and that 1 gallon = 3.79 liters, you calculate the mass of water and use that mass to give you the heat gained by the water?

Sponsored Links