Total Pressure (TP) is defined as

Total Pressure (TP) is defined as

• A. The sum of VP and SP (TP = SP + VP)
• B. The cross-sectional area of duct
• C. The velocity of air
• D. The pressure exerted by air in motion

Answer: (A)

Total pressure in a flowing gas is the combination of the pressure that exists when the fluid is at rest (static pressure) and the pressure due to the fluid’s motion (dynamic or velocity pressure). Static pressure is what you’d measure with no flow, acting equally in all directions on surfaces. Velocity pressure represents the kinetic energy of the moving air and is calculated from 1/2 times the fluid density times velocity squared. When the flow is slowed to zero, that velocity pressure adds to the static pressure, giving the stagnation or total pressure. That’s why total pressure equals static pressure plus velocity pressure. So the correct definition is the sum of static pressure and velocity pressure. The other options aren’t about pressure in this combined sense: the cross-sectional area of the duct is a geometric property, velocity by itself is not a pressure, and “pressure exerted by air in motion” refers to dynamic pressure only, not the total.

Total pressure in a flowing gas is the combination of the pressure that exists when the fluid is at rest (static pressure) and the pressure due to the fluid’s motion (dynamic or velocity pressure). Static pressure is what you’d measure with no flow, acting equally in all directions on surfaces. Velocity pressure represents the kinetic energy of the moving air and is calculated from 1/2 times the fluid density times velocity squared. When the flow is slowed to zero, that velocity pressure adds to the static pressure, giving the stagnation or total pressure. That’s why total pressure equals static pressure plus velocity pressure.

So the correct definition is the sum of static pressure and velocity pressure. The other options aren’t about pressure in this combined sense: the cross-sectional area of the duct is a geometric property, velocity by itself is not a pressure, and “pressure exerted by air in motion” refers to dynamic pressure only, not the total.