12 lines
543 B
Markdown
12 lines
543 B
Markdown
[[Fluids]]
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Pressure is perpendicular force acting on a surface divided by area.
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# Summary
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* $P=\frac{F_\perp}{A}$
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* Scalar.
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* Incompressible fluids keep constant density and volume when pressure changes.
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* $P=P_0+pgh$
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* At the fluid surface h is 0.
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* Measured in pascals (1 Pa = N/m^2)
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# Absolute vs Gauge Pressure
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Absolute pressure is total pressure: $P=P_0+pgh$, where $P_0$ is a reference pressure such as atmospheric pressure ($P_{atm}$) and gauge pressures is $pgh$. Positive gauge pressure means above atmospheric, negative means below. |