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Homework Help: What force is necessary to barely submerge when given specific gravity& weight in air

  1. Dec 4, 2011 #1
    What force is necessary to just barely submerge (push Mary under fresh water) Mary if her average specific gravity is 0.95 after taking a deep breath and her weight in air is 660 N?


    F=mg ; Force of buoyancy=ρgV;



    F=mg
    660/9.8=mass of air
    mass of air=67.3
    force of buoyancy= 67.3 x 0.95
    =63.94 Newtons

    is this right?!?!?! i am panicking!!! physics is so hard omg. fluids are so difficult to understand!!! waaaaaaaaa
     
  2. jcsd
  3. Dec 5, 2011 #2

    ehild

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    Homework Helper

    Re: what force is necessary to barely submerge when given specific gravity& weight in

    Do not panic!! You have the formula for the buoyant force

    Force of buoyancy=ρgV.

    What do ρ, g, V mean?

    ehild
     
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