How does an increase in speed affect drag?

An increase in speed directly affects drag due to the fundamental principles of aerodynamics. As an aircraft speeds up, the airflow over its surfaces becomes more intense, which results in a rise in drag forces acting against the aircraft's forward motion.

Specifically, there are two main components of drag to consider: parasitic drag and induced drag. Parasitic drag, which includes form drag and skin friction drag, generally increases with the square of the velocity. This means that as speed doubles, the parasitic drag can increase by a factor of four, leading to significantly higher total drag at higher velocities.

Induced drag, on the other hand, is related to lift, and while it specifically decreases with increasing speed (due to the reduction in angle of attack needed to maintain lift), the overall effect of increasing speed is a dominant increase in parasitic drag that most pilots experience under normal flight conditions.

Therefore, the impact of increased speed results in a clear increase in overall drag, making the assertion that drag increases with an increase in speed the correct understanding of aerodynamic principles.