Which calculation helps determine water flow from hydrants?

Hydraulic calculations are essential for determining water flow from hydrants because they involve the study of fluid mechanics, specifically how fluids behave when they move through pipes and other systems. These calculations take into account various factors that affect flow, such as pressure, pipe diameter, friction loss, and the elevation changes in the system. By applying the principles of hydraulics, fire engineers can ensure adequate water supply during firefighting operations and assess the performance of hydrants under different conditions.

In contrast, Bernoulli's principle, while related to fluid dynamics, primarily addresses the conservation of energy in flowing fluids and is often used in a different context. Ohm's Law pertains to electrical circuits and does not apply to fluid dynamics. Newton's Laws of motion deal with the forces acting on objects and their movement, which, while foundational in physics, do not specifically address the behavior of fluids in the context of fire hydrant flow.