Dynamic pressure is most directly related to which factor?

• A. Pressure due to altitude
• B. Additional pressure caused by air in motion
• C. Ambient pressure
• D. Total pressure

Answer: (B)

Dynamic pressure is the pressure created by the motion of air. It’s defined as q = 1/2 ρ v^2, meaning it grows with air density and, especially, with the square of velocity. This is the extra pressure above the surrounding static (ambient) pressure that results when air is moving. It isn’t about altitude, which affects static pressure, nor is it simply ambient pressure, which is the static pressure at a point. It’s also not the total pressure, which is the sum of static and dynamic pressures. In a Pitot-static system, dynamic pressure is the portion due to air in motion and is directly linked to how fast the air is moving (and how dense it is), which is why it’s used to infer airspeed.