Fluid statics or hydrostatics is the branch of fluid mechanics which deals with the study of fluids at rest and the pressure exerted by it on an immersed object. If your question is about the study of fluids in motion, use the tag "fluid-dynamics" instead.
Questions tagged [fluid-statics]
1649 questions
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Why does a cup with 100 g water float when placed on another cup with 50 g of water?
Imagine we have cup A with 50 g of water and cup B (smaller in width than A) with 100 g of water. Now put cup B into cup A. If the width of both cups are of comparable size then the cup with 100 g of water floats. It does not touch the bottom of cup…
quantum
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33
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6 answers
Why should water fall down from an upside down glass of water?
Suppose I have an upside down glass of water that I somehow brought in the configuration shown below (without any air between the glass and water). Now the water will obviously fall down but my question is why exactly?
The forces on the water column…
FullBridge
- 477
24
votes
5 answers
Pressure difference in bottles connected by pipe
I was making a school project for my younger brother. Two bottles are taken and attached to each other using a pipe. To one bottle, the pipe is inserted almost at the bottom and the other almost at the middle of bottle. When i filled one bottle with…
Jatin Gakhar
- 341
10
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4 answers
When is a water level no level?
We are all familiar with the ancient but much venerated and still in use today water level.
It's simple, right?
You fill a tube with water, make sure that all of the bubbles are excluded, and then the two water surfaces - one in each leg of the tube…
Badger
- 109
8
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4 answers
Why doesn't hydrostatic pressure glue objects to the seafloor?
Consider a cement block of the same density as sea-water resting on the (perfectly polished) seafloor. I also assume the side-faces of the cement block are highly polished, so that no vertical hydrostatic forces can attack on them. A cable is…
yippy_yay
- 2,598
5
votes
1 answer
Can sand falling in a floating hourglass cause it to sink? (Follow up to hourglass question)
This is related to this question:Does the weight of an hourglass change when sands are falling inside?
At Brigham Young University, there is a display consisting of a sealed off liter bottle with a sunken sealed off hourglass. When one turns over…
Brian Rushton
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5 answers
Atmospheric Pressure inside a closed room
Even though they’re too tiny to see, all the molecules of air in the atmosphere above your head weigh something. And the combined weight of these molecules causes a pressure pressing down on your body of 10,000 kg per square metre. This means that…
The Cryptic Cat
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3
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1 answer
Surfactants from bulk to the interface
Surfactants are known to adhere to the interface. What's the physical mechanism for the transport of surfactants from the bulk to the interface?
Wiz123
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3
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Pressure at a Given Depth: Impossible Result
Let's say there's a static fluid in an arbitrarily deep vessel with constant non-zero compressibility ($k=\frac{1}{B}=-\frac{dV}{Vdp}=\frac{d\rho}{\rho dp}$). Let $z$ be the vertical distance below the surface of the fluid. Then $dp=g\rho dz$ ($g$…
Joshua Meyers
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3
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Height difference between when cup with block of lead inside floats and block of lead sinks
A pot is partially filled with water, in which a plastic cups is floating. Inside the floating cup is a small block of lead. When the lead block is removed from the cup and placed in the water,
block sinks to bottom. When this happens, does the…
Azz Likar
- 31
3
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2 answers
Why is horizontal pressure the same as vertical pressure in a static fluid?
In a static fluid, I know that because it is not moving, the pressure from the top equals the pressure from the bottom.
Also, using the same logic, the pressure from the sides must be the same.
Why are the pressures in all directions equal? It…
63677
- 149
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3
votes
1 answer
Atmospheric pressure in a mercury barometer in an upward accelerating elevator
I have an elevator accelerating upwards at an acceleration of $a$. A mercury barometer measures the atmoshperic pressure at this point. Will the reading be less than, more than or equal to $76 \ cm$ of $Hg$?
I remembered from my class that the…
Gerard
- 2,730
2
votes
1 answer
Does a non-uniformly-dense pyramid floating in water displace more water/"float lower" than a uniformly dense one?
Consider two square, equilateral pyramids of equal volume $V_{object}$ and equal mass.
One pyramid is uniformly dense
The other pyramid has most of its mass concentrated at the apex.
Both pyramids have an (equal) overall density $\rho_{object}$…
Bunji
- 1,290
2
votes
1 answer
Is it impossible to use a 1m by 1m suction cup?
I was learning about fluids and I randomly thought of suction cups. I think they're a really cool application of air pressure. When you squeeze the air out, the outside air pressure exerts a huge force on the cup, meaning it will hold in…
John Hon
- 2,306
2
votes
2 answers
An inverted bottle stops water flow, but does not when connected by a tube?
I'm wondering why an inverted bottle doesn't overflow a container it fills once it reaches the opening, but when a tube is used then the water drains out completely causing the container to overflow and the bottle to become crushed/implode?
I think…
thorie
- 23