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Re: [Phys-l] buoyancy



Quoting John Denker <jsd@av8n.com>:
Personally, I am perfectly happy with equating buoyancy with the
weight of the displaced fluid. This works in simple situations,
and in non-simple situations the very notion of "the" buoyant
force is ill-defined.

The buoyant force for a partially immersed object, for example, should not be simply defined as the weight of the fluid displaced. For smaller object, the surface tension may not be negligible.

In addition, the buoyant force, in this case, is the resultant force due to two different kinds of pressure: air pressure and liquid pressure. The air pressure is contributed by the collisions of gas molecules which is dependent on their random kinetic energies or the absolute temperature. For the liquid pressure, it is contributed by the density of liquid and the gravitational force on these molecules...


Best regards,
Alphonsus