Question

We talked about how airflow above and below an airfoil allows planes and helicopters to fly. Which of the following statements best fits the mechanism by which this works?

a) Airflow above the wing is at a higher flow velocity and lower pressure than below the wing.
b) Airflow above the wing is at a lower flow velocity and lower pressure than below the wing.
c) Airflow above the wing is at a lower flow velocity and higher pressure than below the wing.
d) Airflow above the wing is at a higher flow velocity and higher pressure than below the wing.

Answer 1

Airflow above the wing is higher in velocity but lower in pressure compared to the air below, which creates lift according to Bernoulli's principle. This lift is essential for an aircraft's ability to fly, and the same concept applies to the forward force on sails. Option A is correct.

Step-by-step explanation:

The mechanism by which airflow above and below an airfoil, such as a wing, allows planes and helicopters to fly can be best explained through Bernoulli's principle.

The correct answer to the question is a) airflow above the wing is at a higher flow velocity and lower pressure than below the wing. According to Bernoulli's principle, when air travels faster over the upper surface of the wing, the pressure above the wing is reduced in comparison to the pressure below the wing.

This difference in pressure creates a net upward force or lift, allowing the aircraft to ascend. This principle is also applied in the case of sails, where the pressure on the front side of the sail (Pfront) is lower than the pressure on the back of the sail (Pback), resulting in a forward force.

It is also important to note that lift is not solely a result of pressure differences; it can also be partially created through the conservation of momentum, as air is deflected downward, which according to Newton's third law, results in an upward force on the wing.