Which of the following factors can influence the effectiveness of an aerofoil?

The effectiveness of an aerofoil is primarily impacted by its angle of attack and shape, making this choice the most accurate.

The angle of attack refers to the angle between the chord line of the wing and the oncoming airflow. As this angle increases, it can significantly alter the lift produced by the aerofoil, up to a critical angle where stall occurs. The shape of the wing, or the aerofoil profile, also plays a crucial role in determining lift characteristics, drag, and overall performance. Different wing shapes can optimize performance for various flight conditions, influencing both lift generation and aerodynamic efficiency.

Factors such as altitude and humidity levels, while they may affect the overall performance of an aircraft, do not influence the design of the aerofoil directly. Changes in altitude can affect air density, which impacts lift, but the fundamental effectiveness of the aerofoil itself remains tied to its angle of attack and geometry. Aircraft weight and power settings are operational factors that affect flight dynamics but are not inherent to the aerofoil's design or effectiveness. Engine efficiency and wing tips relate to other aerodynamic considerations that can enhance performance but do not define how effective an aerofoil is in generating lift at a given angle of attack or shape.