How High Can Pumped Water Reach in a Building Fire?

AI Thread Summary
The discussion focuses on calculating the maximum height water can reach when pumped from a fire hose during a building fire. The water exits the hose at a rate of 2 liters per second and at an angle of 75 degrees from a height of 1.5 meters. The key equations involved are Bernoulli’s equation and the equation of continuity, which help determine the water's velocity and trajectory. The problem is ultimately framed as a projectile motion scenario, simplifying the analysis to treat the water as a projectile rather than a fluid under pressure. Understanding this perspective allows for a straightforward calculation of the water's maximum height.
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Homework Statement



There is a fire in a building, so the fireman connects a hose to a hydrant that pumps 2 litres of water per second. The exit of the hose has and area of 15cm^2.
Which is the maximum floor of the building that the water can reach considering that it exits the hose at an height of 1,5m from the ground with an angle of 75 degrees?


Homework Equations



The pressure in a fluid at depth h in the fluid: p = Po + dgh
Equation of continuity for fluids: A1.v1 = A2.v2
Bernoulli’s equation: p1 + 1/2dv1^2 + dgh = constant

The Attempt at a Solution



Assuming that the area of the exit of the hose is the same of the area where the water exist the hydrant, I can assume using the equation of continuity that the velocity that the water is being pumped will the the same at the exit of the hose and I can find that value.
In this case, should I imagine the water like a solid object being launched from the ground, or is there any other equation to use when we are dealing with fluids?
 
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This is really a "projectile problem." Treat each little parcel of water exiting the hose as a separate (non-interacting) mass. You know the initial velocity of the projectile and the angle that it is launched. Determine the maximum height that the projectile reaches.
 
If you know the velocity of water exiting the hose, do you really need to know anything else to find how high it can go?
 
Thank you for you explanation Chestermiller, now I understand. I was looking at this as a pressure problem, but I just need to see water as a projectile and it's solved :)
 
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