Gauge pressure needed for firehose to spray 20m high

[vachan]

help//// on pressure... !

Homework Statement

What gauge pressure in the water mains is necessary if a firehose is to spray water to a height of 20 ?

Homework Equations

Pressure = density * gravity * chanfe of height

The Attempt at a Solution

density of the water is 100 kg/m^3
so will the solution be:
100 (kg.^3) * 9.8 (m/s^2)* 20m
=19600 pa?

 

[rl.bhat]

To determine the gauge pressure inside a hose pipe you have to apply Bernoulli's principle. Inside the pipe the pressure is P and velocity of flow of water is zero. Outside the pipe pressure is ane atmosphere
= 1.013*10^5 pa. Find the velocity of projection of anybody to reach the height h.Use the equation P + 0 = 1.013x10^5 + 1/2xdensity waterxv^2. Density water is 1000kg/m^3