Bouyant force on a cube floating at the surface between water and oil?

  1. 1. The problem statement, all variables and given/known data
    A cube of 15 cm is floating at the surface between water and oil. The oil has a density of 810 kg/m3. If the cube floats so that it is 52% in water and 48% in the oil, what is the mass of the cube and what is the buoyant force on the cube?


    2. Relevant equations
    Archimede's Principle
    Fb= densityfluidvfluidg



    3. The attempt at a solution
    Not sure how to find the mass of the cube when only the height of one side is given?
     
  2. jcsd
  3. mgb_phys

    mgb_phys 8,952
    Science Advisor
    Homework Helper

    The cube is displacing it's own weight in oil and water.
    it might be simpler to think of it as two (almost ie 0.52/0.48) half cubes immersed in oil and water.
     
  4. fb = (1000*0.52+810*0.48)*0.15^3*9.8
    =30 N

    mass=fb/g
    =30/9=3.33
     
Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?