How does form drag change with speed?

Form drag is the resistance experienced by an object as it moves through a fluid, such as air. This drag is influenced significantly by the shape of the object and the speed at which it moves. As the speed of the aircraft increases, the impact of form drag becomes more pronounced.

Specifically, form drag increases approximately as the square of the speed increases. This relationship can be attributed to the physics of fluid dynamics, where a higher speed leads to a greater relative velocity between the aircraft and the air. When speed doubles, the drag increases by a factor of four because drag is proportional to the square of the speed. This means that if you were to increase your speed, you could expect a much more significant increase in form drag due to the dynamics of airflow around the aircraft, which becomes less efficient at higher speeds.

The other options do not accurately describe how form drag behaves with changes in speed. For example, stating that form drag decreases with speed or remains constant does not align with the established principles of aerodynamics, which show that an increase in speed will lead to increased air resistance. Similarly, the notion that form drag increases linearly with speed neglects the more complex nature of airflow dynamics and does not reflect the square relationship observed in practice.