Which drag is inseparable from the production of lift?

• A. Induced drag
• B. Parasite drag
• C. Skin friction drag
• D. Form drag

Answer: (A)

When a wing produces lift, the air must be deflected downward and vortices form at the wingtips. That downwash creates a rearward, resisting force on the wing, which we call induced drag. Because this drag is a byproduct of generating lift, you can’t have lift without inducing some drag in that manner. The amount of induced drag increases with the lift required and decreases as speed goes up, since higher speeds allow the same lift with less downwash.

Parasite drag, including skin friction and form drag, comes from the airframe’s shape and surface interactions and is not produced by lift itself. It exists regardless of lift and generally grows with speed, but it is not inseparable from lift like induced drag is.