Concept explainers
Reminder:-Round all answers to two decimal places unless otherwise indicated.
Head and Pressure Determining the water pressure at a given location employs the concept of the head, which is the vertical distance, in feet, from the surface of a source body of water to the location. The pressure exerted by water is proportional to the head. If we measure head in feet and pressure in pounds per square inch, then the constant of proportionality is the weight of a column of water that is 1 foot high and 1 inch square at the base. That much water weighs
FIGURE
a. Write an equation that expresses the proportionality relationship between pressure
b. For a pumper truck pumping water to a fire, the back pressure is the additional pressure on the pump caused by the height of the nozzle. Consider a pumper at street level pumping water through a hose to firefighters on the top of the eighth floor of a building. If each floor is
c. Head (and therefore back pressure) depends only on the height of the nozzle above the pumper. It is affected neither by the volume of the water nor by horizontal distance. A pumper in a remote location is pumping water to firefighters on the far slope of a hill. At its peak, the hill is
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