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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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P
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Pressure
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INFOTEXT
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1992-09-02
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In physics, force per unit area. In a fluid
(liquid or gas) pressure increases with
depth. At the edge of Earth's atmosphere,
pressure is zero whereas at ground level it
is about 1013.25 millibars (or 1 atmosphere).
Pressure at a depth h in a fluid of density d
is equal to hdg, where g is the acceleration
due to gravity. The SI unit of pressure is
the pascal (newton per square metre), equal
to 0.01 millibars. Pressure has also been
measured using a mercury column (see
Torricelli); 1 atmosphere equals 760 mm of
mercury.