Which statement about drag components and airspeed is true?

Which statement about drag components and airspeed is true?

• A. Induced drag increases with airspeed; parasite drag decreases with airspeed.
• B. Induced drag decreases with airspeed; parasite drag decreases with airspeed.
• C. Induced drag decreases with airspeed; parasite drag increases with airspeed.
• D. Induced drag increases with airspeed; parasite drag increases with airspeed.

Answer: (C)

Induced drag and parasite drag respond in opposite ways to airspeed. Induced drag is tied to producing lift, so when you fly slower you need a higher lift coefficient and induce more swirl and energy loss, making induced drag larger. As you speed up, the required lift coefficient drops, which lowers induced drag. Parasite drag, on the other hand, comes from the aircraft’s shape, skin friction, and exposed protrusions, and it climbs with dynamic pressure, so it grows with speed. Because of that, the statement that best matches how these components change with airspeed is that induced drag decreases as speed increases, while parasite drag increases as speed increases. This is why total drag shifts from being dominated by induced drag at low speeds to dominated by parasite drag at higher speeds, with a crossover in between.

Induced drag and parasite drag respond in opposite ways to airspeed. Induced drag is tied to producing lift, so when you fly slower you need a higher lift coefficient and induce more swirl and energy loss, making induced drag larger. As you speed up, the required lift coefficient drops, which lowers induced drag. Parasite drag, on the other hand, comes from the aircraft’s shape, skin friction, and exposed protrusions, and it climbs with dynamic pressure, so it grows with speed.

Because of that, the statement that best matches how these components change with airspeed is that induced drag decreases as speed increases, while parasite drag increases as speed increases. This is why total drag shifts from being dominated by induced drag at low speeds to dominated by parasite drag at higher speeds, with a crossover in between.