AFOQT Practice Test

When an airplane increases its lift, what happens to the air pressure above and below its wings?

1. Air pressure is lower above and higher below

2. Air pressure is equal on both sides

3. Air pressure is higher above and lower below

4. Air pressure fluctuates randomly

The correct answer is: Air pressure is lower above and higher below

When an airplane increases its lift, the design of its wings creates a difference in air pressure between the upper and lower surfaces. This phenomenon occurs due to the shape of the wings, known as an airfoil. As the airplane moves, air flows faster over the top surface of the wing than it does underneath. According to Bernoulli's principle, when the velocity of a fluid increases, its pressure decreases. As the airplane generates more lift, the airflow speed above the wings increases further, resulting in a drop in air pressure above the wings. Simultaneously, the air pressure below the wings remains higher because the airflow is slower in that region. This pressure differential between the lower and upper surfaces of the wings contributes directly to the lift generating force that enables the airplane to rise into the air. Thus, when lift increases, the air pressure above the wings is lower and the air pressure below the wings is higher, leading to the effective increase in lift for the aircraft.