Height of fluid and Bernoullis equation

AI Thread Summary
The discussion revolves around a fluid dynamics problem involving Bernoulli's equation and the continuity equation. The user initially miscalculated the velocity in the narrower section of the pipe, leading to an incorrect height difference between two vertical pipes. After realizing a decimal error in the initial velocity, the user corrected their calculations, aligning with the book's answer. The final height difference calculated is consistent with the principles of fluid dynamics. The book's solution is confirmed to be correct after the adjustment.
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Homework Statement



An ideal liquid flows horizontally through a pipe of cross sectional area 3cm2 with a velocity 1ms-1. The pipe narrows to a cross sectional area 1cm2. 2 vertical pipes are connected to the pipe, one in either region.
Calculate the height difference of the liquid between the 2 vertical pipes.


Homework Equations



p1 + 0.5ρv12 + ρgh1 = p2 + 0.5ρv22 + ρgh2

A1v1 = A2v2


The Attempt at a Solution



I think I'm a bit confused on what my variables represent in bernoullis equation:
Using the continuity equation gives v2 = 3ms-1.
Then I said that for the pipes p1 = p2 (because they're both open to the atmosphere), putting everything into bernoullis equation and rearranging gives
h1 - h2 = 0.4 m
The book says the answer is 4x10-3 m.

Am I not allowed to consider the heights of the fluid in the vertical pipe because I calculated the speeds of the fluid in the horizontal pipe? I can't think of any other way to do the problem.
 
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Oh sorry nevermind, I got it.
Turns out the velocity is initially 0.1 ms-1, then doing what I said gives the answer.

:)
 
IMO, the book's answer is wrong.

I see that the OP had missed a decimal in the initial velocity. Book answer is OK.
 
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