
#1
Mar2212, 11:36 AM

P: 46

Why isn't the influence of air pressure assimilated in Archimedes law?
If an obect is more dense than the fluid, it wil sink. That is clear, but suppose I could lower down de air pressue, so less force that tends to push the object tot the surface. Is there any situation possible of adjusting the air pressure to get an object just floating? Or is the influence of the air pressure in incompressible fluids not great, so change in pressure wouldn't be noticed very much? But , think of it as an theoretical question. thank in advance 



#2
Mar2212, 02:42 PM

Sci Advisor
P: 5,937

The key factors are the density of the fluid and the object, with gravity the controlling force. Air pressure plays no role.




#3
Mar2312, 03:56 AM

P: 46





#4
Mar2312, 07:32 PM

Sci Advisor
P: 5,937

archimedes law 



#5
Mar2312, 08:23 PM

Sci Advisor
P: 3,138

An object immersed in air experiences bouyancy.
I think it IS accounted for in Archimedes' law. You answered your question in OP. In slide rule days the effect was too small to warrant consideration, but with today's umpteendigit calculators i'm sure it could be included. Try it and see how many digits out it shows up. From wiki, http://en.wikipedia.org/wiki/Properties_of_water 



#6
Mar2312, 09:34 PM

P: 4,664

http://www.google.com/webhp?rlz=1C1R....,cf.osb&cad=b 



#7
Mar2912, 05:24 AM

P: 46

http://en.wikipedia.org/wiki/Buoyancy grtz 



#8
Mar2912, 06:24 AM

P: 1,904

The results that atmospheric pressure does not directly influence buoyancy is due to the buoyancy depending on the pressure difference (or gradient) along the vertical direction. Atmospheric pressure just adds a constant factor to the hydrostatic pressure and this has no contribution to the gradient. 



#9
Mar3012, 06:06 AM

P: 46

The object remains in static equilibrium because of difference in de weight of the air pushing downwards. thank for all the help 


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