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What to use when equations require mass but given a volume ?

  1. May 31, 2015 #1
    In some questions, I've noticed that some questions which relate to equations that involve mass (Kg) and I am given a volume.

    e.g
    http://gyazo.com/169d40e27c5a14508724cb574635aca8

    Know I that Δu=mCΔT, and I know that Δu=400w x t = m x 4200 x 60
    and solve for t, but do I assumption that 1Kg = 1 L ?
     
  2. jcsd
  3. May 31, 2015 #2

    rock.freak667

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    Homework Helper

    You were given the volume of 1 L and a density of 1 g/cm3.

    What's the definition of density?
     
  4. May 31, 2015 #3
    Mass = Density x Volume

    So would I convert the density to kg/m3 which is basically x1000 ?
    and so the volume is 0.001m3
     
  5. May 31, 2015 #4

    rock.freak667

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    Yes that's correct.

    So you multiply the two and you get your mass in kg.
     
  6. May 31, 2015 #5
    Have I done the question correctly ? (ignoring units) Mass = 1kg
    400xt=1x4200x60

    So the time is 630 seconds ?
     
  7. May 31, 2015 #6

    rock.freak667

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    Homework Helper

    Yes that should be correct.
     
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