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

by kalisious
Tags: bouyant force, floating, fluids, mass
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Nov11-09, 09:11 PM
P: 13
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?
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Nov11-09, 10:11 PM
Sci Advisor
HW Helper
P: 8,953
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.
Dec1-09, 01:05 PM
P: 1
fb = (1000*0.52+810*0.48)*0.15^3*9.8
=30 N


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