As airspeed decreases, which type of drag increases?

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

Answer: (A)

Induced drag is the portion of total drag that comes from producing lift and the associated wingtip vortices. As airspeed decreases, a wing must produce more lift to support the same weight in level flight, which means a higher lift coefficient and stronger wingtip vortices. Those stronger vortices create more downwash and a larger backward component of the aerodynamic force, which we experience as increased induced drag. In simple terms, induced drag grows as speed goes down (it varies roughly inversely with speed), while parasite drag grows with speed. Since parasite drag includes form drag and skin-friction drag and both rise with speed, they don’t increase when you slow down. At slower speeds, induced drag becomes the dominant drag component, making it the correct choice.