If speed increases, what happens to the pressure energy?

If speed increases, what happens to the pressure energy?

• A. Decreases
• B. Increases
• C. Remains the same
• D. Converts to kinetic energy

Answer: (A)

In steady, incompressible flow, the total energy per unit volume along a streamline stays about constant, so speed and pressure trade off. This is Bernoulli’s idea: P plus 1/2 ρ v^2 remains constant. When the fluid speeds up, the kinetic energy term 1/2 ρ v^2 increases, so the static pressure P must drop to keep the sum the same. In other words, pressure energy decreases as speed increases, with some of the energy shifting into kinetic energy to boost velocity. This is the same reason you see lower pressure in a constricted path, like a venturi or a narrowed blood vessel.

In steady, incompressible flow, the total energy per unit volume along a streamline stays about constant, so speed and pressure trade off. This is Bernoulli’s idea: P plus 1/2 ρ v^2 remains constant. When the fluid speeds up, the kinetic energy term 1/2 ρ v^2 increases, so the static pressure P must drop to keep the sum the same. In other words, pressure energy decreases as speed increases, with some of the energy shifting into kinetic energy to boost velocity. This is the same reason you see lower pressure in a constricted path, like a venturi or a narrowed blood vessel.