Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: RAIN FALL QUESTIONS-CAN'T FIND PART 4 about kg!

  1. Sep 9, 2010 #1
    RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    1. The problem statement, all variables and given/known data

    During a thunderstorm, a total of 0.9 inches of rain falls. How much water falls on one acre of land? (1 mi2 = 640 acres) Express your answer in the following ways.

    I found ft^3, m^3, and in^3, but I'm stumped on part 4...where it asks for kg??

    2. Relevant equations

    I found 564376 in^3, 3267 ft^3, and 92.5111378 m^3 and I know these 3 parts are 100 percent correct?
    JUST NEED HELP WITH PART 4 ON HOW TO FIND kg!
    Thanks in advance guys!


    3. The attempt at a solution
     
  2. jcsd
  3. Sep 9, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    A relevant equation you will need is density, ρ=m/V.

    What is the density of water ?
     
  4. Sep 9, 2010 #3
    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    SORRY!!!

    NOTE: Density of 1000kg/m^3!

    Thanks. sorry again
     
  5. Sep 9, 2010 #4

    rock.freak667

    User Avatar
    Homework Helper

    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    Well then, if you have the formula ρ=m/V, you know 'ρ' and you know 'V', you want to find 'm', rearrange the formula and make 'm' the subject.
     
  6. Sep 9, 2010 #5
    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    i still dont get it??? i know my mass is x, what is the density in this problem??? Would i take the 1000kg/92.5111378 m^3????? and then my volume is 92.5111378 m^3....so I would get m=dv....so d=10.8095 and then v is 92.5111378 m^3, d times v equals 1000?
     
  7. Sep 9, 2010 #6

    rock.freak667

    User Avatar
    Homework Helper

    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    m=ρV.

    You told me density ρ=1000kg/m3

    And the volume V=92.5111378m3?

    Just substitute into the formula.
     
  8. Sep 10, 2010 #7
    Re: RAIN FALL QUESTIONS---CAN'T FIND PART 4 about kg!

    SO the answer is 1000kg after doing the math out?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook