The lift on an aeroplane wing arises because
Correct answer: A. air moves faster over the curved upper surface, lowering the pressure there
- A. air moves faster over the curved upper surface, lowering the pressure there
- B. air moves faster under the wing
- C. the wing is lighter than air
- D. the engines push the wing upwards
Explanation
The aerofoil shape makes the air travel further and faster across the top, so by Bernoulli's principle the pressure above is lower than below and the difference multiplied by the wing area gives the lift. The wing also deflects air downwards, and by Newton's third law that contributes lift as well. Both descriptions are valid ways of accounting for the same force.
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About Bernoulli's Equation
Bernoulli’s equation applies conservation of energy to steady flow of an incompressible, non-viscous fluid along a streamline: pressure, kinetic and gravitational terms have a constant total. It explains pressure-speed changes in narrow pipes, Venturi meters and lift, and differs from continuity because it relates pressure as well as velocity and height.
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