A fluid….  Include BOTH gases and liquids!  There are a couple of gas laws (Boyles’ and Charles’). The rest of this unit applies to all fluids equally.

Boyles Law  Volume of a gas is inversely proportional to pressure.

Charles Law  Volume of a gas is directly proportional to temperature.

Pascal’s principle  Honors P329, reg. P326  Pressure: Ratio of force to area P = F/A  Units: P, Pascal (Pa) : F, Newton (N) : A, meter 2 (m 2 ) A, meter 2 (m 2 )  Pascal’s Principle: “Any change in pressure in an enclosed, static fluid is transmitted equally to all parts of the fluid and the container walls”.  What does “static” mean?  Examples of Pascal’s principle include a hydraulic car jack, a hydraulic ram etc.

– Ex: car jack has small piston area = 1.0 X10 -6 m 2 and a large piston of 0.50 X10 -4 m 2. –How much can it lift if the small piston is pushed down with a force of 180N? –Given:Pascal says P 1 = P 2,So F 1 / A 1 = F 2 / A 2 –Rearrange to get F 2 on its own F 2 = A 2 F 1 / A 1 – So substitute to solve…. – Tonight for homework do P P1P1 P2P2

Important general rules…..  Fluids flow from areas of ______ pressure to areas of ____ pressure.  Think about how air leaves a tire with a puncture …. From ____ to _____ ……  Pressure in a fluid at any point pushes equally in all directions

Bernoulli’s Principle  Daniel Bernoulli (Swiss) in the early 1700’s observed that air and other fluids do not behave as one would expect. Specifically:  “A fluid moving at a high velocity exhibits LOW pressure. A fluid moving at a low velocity exhibits HIGH pressure.”  This principle explains many phenomena:  Being pushed into path of speeding vehicle, a carburetor and many more…..

Shower curtain pushed in

House roof coming off in tornado

Curve balls in any ball sport

Lift from an airfoil (wing)

Where to find Bernoulli’s Principle in your book..  Honors: P 343- P344  Regular : P335