Find the speed of fluid using bernoulli

AI Thread Summary
The discussion revolves around using Bernoulli's equation to find the speed of fluid in a pipe. The user sets the pressure at both the surface and the exit as atmospheric pressure and assumes the initial velocity and height are zero. This simplifies the equation to derive the fluid velocity as v = √(2gh). Participants confirm the correctness of the solution and clarify the reasoning behind the assumptions made, particularly regarding pressure and velocity. The conversation concludes with a mutual understanding of the application of Bernoulli's principle in this context.
songoku
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Homework Statement


untitled-7.jpg


Find v


Homework Equations


Bernoulli


The Attempt at a Solution


Here's what I've done

I took the surface of water as first reference and the right-end of the pipe as second reference, so:

P1 + 1/2 ρV12 + ρgh1 = P2 + 1/2 ρV22 + ρgh2

P1 = P2 = Patm and I assumed v1 = 0 and h1 = 0, then the equation became:
0 = 1/2 ρV2 - ρgh
v = √(2gh) ---> ta daa, I'm finished with degree of confidence 0.5 % that my answer is correct.

Do I get it right? Thanks
 
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It is 100% correct.

However to build up your confidence let's just clear up how we got here.

After applying the equations, we realized two things.Pressure at surface and Pressure at exit are same as they are open to atmosphere.

Then we made velocity zero.
That was using equation of continuity as surface area of water is much greater than that of pipe.
 
Ah I get it. Thanks for the help :smile:
 
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