Bernoulli's Principle

• states that the pressure of a fluid decreases at the region where the speed of fluid flow increases.

Applications of Bernoulli's Principle


1. Aerofoil

• a curved wing used to produce a lift.
• the pressure difference between the air below and above the aerofoil produces a resultant upwards force known as a lift.
• if the airplane is moving with constant speed, then :                                                                                              a) lift = weight                                                                                                                                                   b) thrust = drag

2. Carburettor

• used to produce a mixture of petrol and air which can be burnt easily in the engine of a car.
• air flowing at a higher speed through the narrow section causes the air pressure there to become lower
• the atmospheric pressure pushes the petrol from the tank to flow out through the jet as a spray of petrol vapour after mixing with air.

3. Bunsen Burner

• when it is connected to the gas supply, gas gusts out through the jet with high speed which creates a low pressure around the jet.
• the outside air at atmospheric pressure which is higher is sucked into the low pressure region.
• the mixture of air and gas which enters the barrel is then burnt to produce a flame.

4. Insecticide Spray

• when the plunger is pushed into the cylinder, air gusts out at high speed through the narrow opening which produces a low pressure region.
• the air above the insecticide is at atmospheric pressure which is higher, so it pushes the insecticide to rise through the metal tube.

Video Tutoring on Bernouli's Principle

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