What is lift?

What is lift?

• A. The forward force produced by aircraft engines
• B. Air resistance against the aircraft that slows it down
• C. The gravity acting on the mass
• D. The upward force generated by the wings. It is created by the flow of air over the wings

Answer: (D)

Lift is the upward force on an aircraft’s wings that makes flight possible. It arises when air flows around the wing in a way that creates a pressure difference: air speeds up over the top surface and slows under the bottom, producing lower pressure above and higher pressure below, which pushes the wing upward. The wing also deflects air downward, and by Newton’s third law, that downward deflection generates an upward reaction on the wing. Lift acts perpendicular to the flight path and must balance weight for steady, level flight. It’s the upward force generated by the flow of air over the wings, not something caused by engines or air resistance alone.

Lift is the upward force on an aircraft’s wings that makes flight possible. It arises when air flows around the wing in a way that creates a pressure difference: air speeds up over the top surface and slows under the bottom, producing lower pressure above and higher pressure below, which pushes the wing upward. The wing also deflects air downward, and by Newton’s third law, that downward deflection generates an upward reaction on the wing. Lift acts perpendicular to the flight path and must balance weight for steady, level flight. It’s the upward force generated by the flow of air over the wings, not something caused by engines or air resistance alone.