If the cross-sectional area is 6 square units and the velocity is 20 units per minute, what is the air flow?

If the cross-sectional area is 6 square units and the velocity is 20 units per minute, what is the air flow?

• A. 120
• B. 40
• C. 6
• D. 20

Answer: (A)

Air flow is the volumetric flow rate, found by multiplying the cross-sectional area by the velocity: Q = A × v. Here A is 6 square units and v is 20 units per minute, so Q = 6 × 20 = 120 cubic units per minute. That unit combination—area times velocity—gives flow rate, which is why 120 is the correct value. The other numbers would reflect only one of the quantities or a mismatched calculation, not the actual flow rate.

Air flow is the volumetric flow rate, found by multiplying the cross-sectional area by the velocity: Q = A × v. Here A is 6 square units and v is 20 units per minute, so Q = 6 × 20 = 120 cubic units per minute. That unit combination—area times velocity—gives flow rate, which is why 120 is the correct value. The other numbers would reflect only one of the quantities or a mismatched calculation, not the actual flow rate.