The plane is heavy and there’s gravity on earth. How does it just fly without falling down?
In: Physics
The plane’s wings are shaped in a way that when they’re moving quickly, the air going over the wing goes faster than the air under the wing. This difference in air speeds causes a difference in air pressure – the air pressure above the wing is lower than the air pressure below the wing. The pressure difference results in an upward force that we refer to as “lift.”
If a plane generates a lift force that is greater than the force of gravity pulling down, it goes up. If the lift force isn’t quite as high as gravity, the plane goes down. When the lift force and gravity are balanced, the plane stays at the same altitude.
The pilot has various controls to adjust the amount of lift the plane is producing, and thus can control the plane’s altitude – to make it climb, to make it hold consistently at cruising altitude, and to lower it gradually when it’s time to land.
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