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Research for a book - Would it float question

  1. Aug 21, 2009 #1
    It has been many years since my studies in physics and engineering in college. My wife is writing a novel, and had a question that I struggled to answer.

    If there were a container (empty) constructed of steel with a mass of 8000lbs, with dimensions of 40ft/8ft/8ft (assume inner dimensions); would it float in the ocean or sink to the bottem. The container is air tight and sealed.

    Thank you in advance for any thoughts!

  2. jcsd
  3. Aug 21, 2009 #2


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    Staff: Mentor

    Welcome to the PF, Michael. If you had a volume of water equivalent in size to that container, how much would that water weigh? More or less than the 8000lbs?
  4. Aug 21, 2009 #3
    40*8*8 = 2560 cu ft
    ~62 lbs/cu ft
    160,000 lbs of water
    Therefore float.

    And could hold around 152,000 lbs of cargo before sinking?

    Is that correct?
  5. Aug 21, 2009 #4


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    Staff: Mentor

    Looks basically correct. Remember about the cargo, though, that the vessel has to be strong enough to hold the load. But otherwise, it looks correct.

    BTW, the floating thing is called Archimedes Principle. Here's more reading if you're interested:


  6. Aug 21, 2009 #5
    Thanks! It is all starting to come back now :) I appreciate the help!

  7. Aug 21, 2009 #6


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    Gold Member

    Let us know if she gets published. I wouldn't mind reading it.
  8. Aug 21, 2009 #7
    Will do!
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