Which statement best defines static pressure?

• A. The force exerted by a moving fluid
• B. The force exerted by an enclosed, non-moving fluid when pressure is applied to the fluid
• C. The atmospheric pressure
• D. The pressure drop across a valve

Answer: (B)

Static pressure is the pressure a fluid exerts on surfaces when the fluid is at rest, representing the force per unit area transmitted through the fluid regardless of any flow. The best statement captures this by describing an enclosed, non-moving fluid where pressure is applied to the fluid—the fluid is at rest and the pressure is transmitted to the walls. When a fluid is moving, part of the pressure is converted to motion (dynamic pressure), so the description would no longer define static pressure. Atmospheric pressure is a reference level, not the general definition of static pressure, and a valve’s pressure drop describes loss due to flow, not the static pressure inside a stationary fluid.