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Homework Help: Estimate Water Volume

  1. Jan 26, 2012 #1
    1. The problem statement, all variables and given/known data
    A violent rainstorm dumps 1.7 cm of rain on a city 4.0 km wide and 7.0 km long in a 2.0 hr period. How many metric tons of water fell on the city?

    2. Relevant equations

    1 ton = 10^3 kg
    1 cm^3 of water has a mass of 1 g = 10^-3 kg.
    Density of water is 1.0 g/cm^3

    3. The attempt at a solution

    Knowing that density of water is 1.0 g/cm^3...

    I first calculated the volume, which is v = (1.7 cm) (4000 cm) (7000 cm) = 4.76E7 cm^3. To get the mass in metric tons, I did the following: mass = (4.76E7 cm^3) (1 g/cm^3) (1 kg / 1 000 g) (1 metric ton / 1000 kg) = 47.6 metric tons.

    When I entered it into the computer, it said it was incorrect. Please help!
     
  2. jcsd
  3. Jan 26, 2012 #2

    256bits

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    Gold Member

    If 1 metre = 100 cm and 1 km = 1000 m, then 4.0 km = how many cm??
    And for 7.0 km??
     
  4. Jan 26, 2012 #3
    Wow. Thanks, man. I messed up the conversion factor. No wonder why I keep getting it wrong. lol Thanks again! I don't know how I could have missed that!
     
    Last edited: Jan 26, 2012
  5. Jan 26, 2012 #4
    Finally got it!
     
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