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what are the applications of bernouli's principle?
It follows from Bernoulli's theorem that whenever a flowing fluid speeds up,there is a corresponding decrease in the pressure and/or  the potential enegy of the fluid.If the flow is horizontal,the whole of the velocity increase is accounted for by a decrease in pressure.Let's discuss a few applications:

(a) Blowing off roof in wind storm.When wind flows with a high velocity above the roof of a house it causes a lowering of pressure above the roof. However, pressure below the roof is still atmospheric. If the wind blow fast enough, the internal air pressure(atmospheric) can blow the roof off. Let us calculate the upward force on the roof during wind storm. Air above the roof pushes down with a force F1 = P1A where P1 is the air pressure above the roof and A is the area of the roof. The air inside the house pushes up with a force F = Pa A where Pa is the atmospheric pressure of the air inside the house. The net upward force is

         Fnet = F - F1 = Pa A - P1A = A(Pa - P1)

A small pressure difference over a large area can produce a large upward force.
(b) A suction effect is experienced by a person standing close to the platform at a station when a fast train passes.The fast - moving air between the person and the train produces a decrease in pressure and the excess air pressure on the other side pushes the person towards the train.


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