Velocity pressure measured by a Pitot tube is best described as which of the following?

• A. Static pressure
• B. Normal-operating pressure
• C. Flow pressure
• D. Atmospheric pressure

Answer: (C)

Velocity pressure is the dynamic component of the air pressure—the pressure due to the air’s motion. A Pitot tube facing the flow measures stagnation (total) pressure, and by comparing it to the static pressure, you isolate the velocity pressure. This quantity represents the energy in the moving air and is used to calculate velocity via q = 1/2 ρ V^2. It’s not static pressure (which exists even without flow) and not atmospheric pressure (the ambient outside pressure). It’s the flow-related, dynamic pressure—the flow pressure.