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Homework Help: Amount of watts needed to heat water

  1. Nov 27, 2006 #1
    I have a problem where I have a cup of water and I have to find out how much power I need to generate to heat it by a certian amount. I cant seem to find the equation I need in my book, can someone help me out? thanks.
     
  2. jcsd
  3. Nov 27, 2006 #2

    berkeman

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    Staff: Mentor

  4. Nov 27, 2006 #3
    ok., now im just trying to figure out how many watts = a calorie. is it 0.239 calories = 1 watt?
     
  5. Nov 27, 2006 #4

    berkeman

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    Keep in mind that a calorie is a unit of energy, and a watt is a unit of power. Do you know how to convert from power to energy? (hint -- keep track of your units so you don't mix seconds and hours, etc.)
     
  6. Nov 28, 2006 #5
    i dont know, how do i convert watts to calories?
     
  7. Nov 28, 2006 #6

    berkeman

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    It says how right at the top of the wikipedia page that I posted a link to. Use the small calorie (gram) definition.
     
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