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Homework Statement
What gauge pressure is required by city mains for a stream from a fire hose connected to the mains to reach a vertical height of 15m?
Homework Equations
Bernoulli Equation:
Thanks once again gneilIn a picture:
View attachment 109402
No, only two points are required on a continuous streamline. Bernouolli is an energy conservation equation, and thus so long as no unaccounted external forces or energies affect a parcel of fluid from one end to the other of the streamline you can ignore the details of pressure and velocity changes along the way.Thanks once again gneil
I could not understand what this horizontal movement of water has to do with the pressure required to throw water upto 15m height. Actually, in my view, the real story starts when water shoots out of the hose. We need to know pressure at the instant. Moreover in your solution we have taken three points where Bernoulli equation is to be applied. The starting point where you took v=0 and the end of the hose pipe and the top of the building. If height delta h is to be taken, then we have to think a virtual pipe starting from end of the city main fire hose to the top of the building.
Yes, that's a valid approach too. Torricelli's theorem can be obtained via Bernoulli, of course.I have another suggestion. If we apply Torricelli theorem and find velocity at the bottom of the building and then use that velocity to calculate the required pressure, then perhaps this problem may be solved.
Thanks dear Sir for your favour.No, only two points are required on a continuous streamline. Bernouolli is an energy conservation equation, and thus so long as no unaccounted external forces or energies affect a parcel of fluid from one end to the other of the streamline you can ignore the details of pressure and velocity changes along the way.
If you use the pressure at the hose exit as a starting point, you won't be using the mains pressure. The moving fluid there will already have a lower pressure than the mains pressure.
Yes, that's a valid approach too. Torricelli's theorem can be obtained via Bernoulli, of course.