Welcome to our exploration of airplane lift! Understanding how airplanes stay in the air involves two fundamental physics principles. First, Bernoulli's principle explains how air pressure differences create lift. Second, Newton's third law shows how deflecting air downward pushes the wing upward. Let's examine how the wing's special shape and angle work together to generate the upward force that keeps aircraft flying.
The key to understanding lift begins with the wing's special shape, called an airfoil. Notice how the top surface is more curved than the bottom. When air flows over this wing, it must travel different distances. The air flowing over the curved top surface has to cover a longer path compared to the air flowing underneath. Since both air streams must reach the trailing edge at roughly the same time, the air on top must move faster to cover the greater distance.
Now we apply Bernoulli's principle to understand how pressure differences create lift. Bernoulli discovered that in a moving fluid, where the speed is higher, the pressure is lower. Since air moves faster over the wing's curved top surface, it creates a region of lower pressure above the wing. Meanwhile, the slower-moving air below the wing maintains higher pressure. This pressure difference - high pressure pushing up from below and low pressure above - creates a net upward force that we call lift.
Newton's third law provides another explanation for lift generation. When the wing moves through the air at an angle called the angle of attack, it deflects the airflow downward. According to Newton's third law, for every action there is an equal and opposite reaction. As the wing pushes air downward, the air pushes back on the wing with an equal force in the opposite direction - upward. The greater the angle of attack, the more air is deflected downward, creating a stronger upward reaction force.
In conclusion, airplane lift results from the combined effect of both Bernoulli's principle and Newton's third law working together. Bernoulli's principle explains how the wing's shape creates pressure differences, while Newton's third law explains how deflecting air downward generates an upward reaction force. These two effects complement each other to produce the total lift force that overcomes gravity and keeps aircraft airborne. Understanding both principles gives us a complete picture of the fascinating physics behind flight.