Which principle describes the inverse relationship between velocity and pressure?

• A. Bernoulli's law
• B. Poiseuille's law
• C. Snell's law
• D. Doppler's law

Answer: (A)

Bernoulli's law is rooted in the principle of conservation of energy for fluid dynamics. It illustrates that in a flowing fluid, an increase in the fluid's velocity occurs simultaneously with a decrease in pressure. This relationship is a fundamental characteristic of how fluids behave in motion.

Bernoulli's equation expresses this balance, highlighting that the sum of the pressure energy, kinetic energy, and potential energy per unit volume remains constant along a streamline. Therefore, if a fluid speeds up as it flows through a narrower section of a pipe (where the cross-sectional area decreases), its pressure must decrease to conserve energy.

This principle is vital in various applications, such as aviation, where the shape of an airplane wing is designed to manipulate airspeed and pressure, enabling lift. Understanding this relationship is crucial for various engineering and physics problems involving fluid flow.