What term describes lift as it relates to the angle of attack?

• A. Lift
• B. Drag coefficient
• C. Moment coefficient
• D. Coefficient of lift

Answer: (D)

The main idea is that lift’s response to angle of attack is described by the coefficient of lift. This is a dimensionless number that relates the lift force to dynamic pressure and wing area: Cl = L / (0.5 ρ V^2 S). It encapsulates how effectively the wing generates lift at a given angle of attack, independent of size or speed. As the angle of attack increases, the coefficient of lift grows (in a roughly linear fashion at lower angles) until reaching a peak before stall. That makes the coefficient of lift the term that directly describes lift in relation to angle of attack. The other terms refer to different things: lift is the actual force, not a normalized measure; drag coefficient relates to drag, and moment coefficient relates to pitching moment, none of which specifically describe lift’s dependence on angle of attack.