How can I calculate h from this diagram

AI Thread Summary
To calculate the manometer reading h, the flow speed at point B was determined using the equation A1V1 = A2V2, yielding a speed of 3.125. The Bernoulli equation was applied to establish a relationship between pressures at points A and B, leading to the expression P(A) = P(B) + 2883. It was emphasized that the pressure difference between A and B must be accurately known, and the forces acting on the mercury in the manometer need to be balanced for equilibrium. Further discussion focused on applying Bernoulli's principle to the mercury in the U-tube without needing the cross-sectional area of the tubing. The conversation highlighted the importance of understanding pressure changes with fluid height or depth.
Furious
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aNbzApR.jpg

Water flows in the horizontal pipe shown in Fig. 13-6. At A the area is
f1064g1q1g1.gif
and the speed of the water is
f1064g1q1g2.gif
At B the area is 16.0 cm2. The fluid in the manometer is mercury, which has a density of
f1064g1q1g3.gif
What is the manometer reading h?

My attempt:
I used A1V1 = A2V2 to find the speed at B which is 3.125
Then I used Bernoulli equation and I have: P(A) = P(B) + 2883
 
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In future, please retain and use the formatting template provided when you start a thread in the homework areas.

Assuming that you have the correct pressure difference between A and B then if you assume some cross-sectional area for the mercury tubing you should be able to assign forces at the mercury surfaces. Since the mercury is in equilibrium, something needs to balance out the forces applied at the surfaces...
 
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gneill said:
In future, please retain and use the formatting template provided when you start a thread in the homework areas.
Noted and addressed.
 
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gneill said:
In future, please retain and use the formatting template provided when you start a thread in the homework areas.

Assuming that you have the correct pressure difference between A and B then if you assume some cross-sectional area for the mercury tubing you should be able to assign forces at the mercury surfaces. Since the mercury is in equilibrium, something needs to balance out the forces applied at the surfaces...
hey, can you please elaborate.
p(a) is applied on left side and on right side p (a) - 2883 but what is the next step?
 
Furious said:
hey, can you please elaborate.
p(a) is applied on left side and on right side p (a) - 2883 but what is the next step?
What might cause a change in pressure with height (or depth) in a fluid?
 
Furious said:
hey, can you please elaborate.
p(a) is applied on left side and on right side p (a) - 2883 but what is the next step?
Furious said:
hey, can you please elaborate.
p(a) is applied on left side and on right side p (a) - 2883 but what is the next step?
You know p1 - p2. Just apply Bernoulli again for the mercury in the U-tube. (You don't need to know the area of either side of the tube; in fact, they can be very different.)
 
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