What type of pressure does water that is not moving exert?

Water that is not moving exerts static pressure. Static pressure is defined as the pressure exerted by a fluid at rest. This type of pressure is important in many applications, such as when calculating the pressure at the base of a reservoir or in a fire suppression system. It is the result of the weight of the water above it and does not vary with the motion of the water, as there is no kinetic energy to influence the pressure.

In contrast, the other terms refer to different concepts within fluid mechanics. Dynamic pressure refers to the pressure of a fluid in motion, reflecting the kinetic energy of the fluid flow. Residual pressure often relates to the remaining pressure in a system after losses due to friction or other factors, typically seen in fire hose systems. Unidirectional pressure is not a standard term used in hydraulics or fluid dynamics discussions. Understanding the distinction between these types of pressures helps in the proper assessment and management of water systems.