In a pipe of varying cross-section, as fluid enters the narrower region it exhibits:
- A. High velocity, high pressure
- B. High velocity, low pressure
- C. Low velocity, high pressure
- D. Low velocity, low pressure
Explanation
Continuity forces the speed up in the constriction, and since the total energy per unit volume is fixed, the gain in kinetic energy must be paid for by a drop in pressure energy. This pairing of fast flow with low pressure is the heart of Bernoulli's principle. A Venturi meter measures flow rate by reading exactly this pressure difference.