Which of the following describes how fluid velocity affects pressure?

• A. Increases pressure with increasing velocity
• B. Decreases pressure with increasing velocity
• C. No effect on pressure
• D. Increases pressure with decreasing velocity

Answer: (B)

The relationship between fluid velocity and pressure is described by Bernoulli's principle, which states that as the velocity of a fluid increases, the pressure within that fluid decreases. This phenomenon occurs due to the conservation of energy in a flowing fluid. When a fluid moves faster, it has more kinetic energy, which means that its potential energy (or pressure energy) must decrease to maintain a constant total energy.

In practical terms, this means that in regions where the fluid velocity is higher—such as in a narrow section of a pipe—there is a corresponding drop in pressure compared to regions where the fluid moves more slowly. This principle is crucial for various applications, including understanding lift in airplane wings and the functioning of venturi meters.

As a result, the description of fluid velocity decreasing pressure with increasing velocity aligns with the established principles of fluid dynamics, confirming the validity of this answer.