An airplane wing is designed to produce lift resulting from

An airplane wing is designed to produce lift resulting from

• A. Positive air pressure above the wing and negative below
• B. Positive air pressure below the wing and negative above along the downward deflection of air
• C. Equal pressures on both surfaces
• D. The wing’s curvature alone, regardless of pressure changes

Answer: (D)

Lift comes from a pressure difference between the wing’s upper and lower surfaces created by the wing’s shape and how it interacts with the air. The curved upper surface makes air accelerate as it flows over the top, which lowers the pressure there. The air beneath the wing moves more slowly and remains at a higher pressure. That difference in pressure pushes the wing upward. Along with this, the wing deflects air downward as it moves through the flow, and the reaction to that downward deflection adds to the upward lift. So lift isn’t produced by curvature alone; it relies on creating a pressure distribution through the wing’s shape and angle of attack, which in turn changes how the air speeds up and where it is pressed. If there were no pressure changes—no difference between the top and bottom surfaces—there would be no net lift.

Lift comes from a pressure difference between the wing’s upper and lower surfaces created by the wing’s shape and how it interacts with the air. The curved upper surface makes air accelerate as it flows over the top, which lowers the pressure there. The air beneath the wing moves more slowly and remains at a higher pressure. That difference in pressure pushes the wing upward.

Along with this, the wing deflects air downward as it moves through the flow, and the reaction to that downward deflection adds to the upward lift. So lift isn’t produced by curvature alone; it relies on creating a pressure distribution through the wing’s shape and angle of attack, which in turn changes how the air speeds up and where it is pressed.

If there were no pressure changes—no difference between the top and bottom surfaces—there would be no net lift.