Name the principle behind the uplift of aeroplane

(a) Conservation of momentum

(b) Bernoulli,s

(c) Newton’s 3rd law

(d) reversibility

Bernoulli's equation or Newton's laws and conservation of momentum all are correct. In the airplane the air is forced downward which clearly implies that there will be an upward force on the airfoil as a Newton's 3rd law reaction force. From the conservation of momentum viewpoint, the air is given a downward component of momentum behind the airfoil, and to conserve momentum, something must be given an equal upward momentum. If we apply the Bernoulli approach to lift point to detailed measurement of the pressures surrounding airfoils in wind tunnels and in flight. Such pressure measurements are typically done with Pitot tubes. Correlating the pressures with the Bernoulli equation gives reasonable agreement with observations.

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