Final answer:
While the specific minimum recommended pressure for a fire hydrant is not provided, typical standards suggest a minimum of around 20 psi. Bernoulli's equation is used to relate pressure with other factors such as flow rate and height in firefighting applications.
Step-by-step explanation:
The minimum recommended pressure for water coming from a fire hydrant is not specified in the provided text. However, for firefighting applications, hydrant pressure is critical in ensuring that water can be effectively delivered to extinguish a fire. Typically, fire hydrants should have a pressure of around 20 psi (137.9 kPa) at a minimum to be able to perform effectively, although local codes and standards can require higher pressures. When considering the pressure in a fire hose nozzle, Bernoulli's equation is often used, which relates the pressure in the hose to the flow rate (40.0 L/s in some examples) and the elevation change (e.g., going 10.0 m up a ladder). High pressures are needed to overcome resistance and to push water to higher elevations. Flow rates and nozzle diameters are also significant factors in determining the functioning pressure within the hose and nozzle, which are often used to calculate the potential height to which water can be projected.