Re: [Phys-L] [SPAM] Another Fluid/Density 'Problem'

["Anthony Lapinski" <Anthony_Lapinski@pds.org>]

For those interested, I found my references for this problem:

Aarons - Teaching Introductory Physics - page 328

Jargodzki & Potter - Mad About Physics - page 29



Phys-L@Phys-L.org writes:
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> An Old Fashioned Glass Milk Bottle with a narrow neck is delivered to
> your doorstep in the morning and because it is no homogenized, the Cream
> has risen up into the narrow(er) region.
>
> The fluid pressure exerted on the bottom of the bottle is (rho) g h.
> Where (rho) is the average density of the column of milk/cream that
> extends from the top surface to the bottom.
>
> Now we will thoroughly MIX the bottle of milk and we note that the
> average density of this same column of milk is GREATER than (rho).
> Let’s call this new density (RHO).
>
> How can the pressure have increased while the area of the bottom has
> stayed constant?
> How can we accept a greater amount of downward fluid force caused by
> ‘just’ mixing the milk?
>
> (This is reprised from back in the last century.)
> Probably presented better back then.
> ;-)