Volume flow is determined by multiplying the cross-sectional area of the vessel by which quantity?

• A. Volume flow rate
• B. Mean velocity
• C. Peak velocity
• D. Minimum velocity

Answer: (B)

The amount of fluid moving through a vessel per unit time (volume flow) comes from multiplying how wide the cross-section is by how fast the fluid is moving on average across that cross-section. In a real vessel, speed isn’t the same everywhere—it's fastest in the center and slower near the walls—so you need the average velocity across the area, not the peak speed. Using the mean velocity gives a true total flow: area times v_mean. Using peak velocity would overestimate flow, and minimum velocity would underestimate it. Volume flow rate is the resulting quantity, not the velocity you multiply by.