How is the angle of attack defined?

The angle of attack is defined as the angle that the wing's chord line makes with the direction of the relative wind. This is a critical concept in aerodynamics because it directly influences the lift generated by the wings of the aircraft. As the angle of attack increases, up to a certain point, the lift generated by the wings also increases, which is essential for an aircraft to climb or maintain altitude.

Understanding angle of attack is crucial for pilots when managing flight conditions, as it affects stall performance and overall aircraft handling. If the angle of attack exceeds a certain limit, the wing can stall, which can lead to a loss of lift and control.

This definition highlights its importance in the aerodynamic performance of an aircraft and how it interacts with airflow, making it a foundational principle in aviation. The other choices refer to concepts that, while relevant to aircraft operation and design, do not accurately capture the specific definition of angle of attack as it relates to aerodynamic principles.