The hydrostatics tag does also apply to fluid-statics.

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Acceleration of an bubble under the sea

An air bubble arises from the bottom of the sea. Find its acceleration if resistance force is proportional to $\rho Av$ where $\rho$ is density of water, $A$ is cross section area and $v$ is velocity ...
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A block floating on water is pushed inside until it touches the bottom. Will the block come back? [duplicate]

A block floating on water contained in a vessel is pushed inside until it touches the bottom of the vessel and then released. Will the block come back? Bouyant force acts because the pressure on ...
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Is there a relationship between maximum flow rate of a fluid through perforations in a cavity and the flow rate of the fluid in the cavity itself?

I have a scenario where water is flowing horizontally through a (rectangular) cavity. The underside of the cavity has a set of perforations that look something like: and I need to determine the ...
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0answers
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How do monitor arm mounts stay up? [closed]

What is the mechanism and also the name of the principle involved in engineering computer displays arm mounts? How does it allow up and down motion without the hinges just dropping the monitor (and ...
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Siphon and a pressure gradient

It's claimed here that the pressure gradient is what sustains the flow in a siphon. But I'm not really accustomed to the term and don't see why it forms and why it sustains the flow. Can you please ...
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How do you compute pressure at a pipe inlet if the pipe is leaking between the inlet and the outlet/pressure measurement point [closed]

This is a real world problem: I have a vertical pipe (a well ~800' deep); I have an unknown but reasonably fixed (artesian) pressure at the pipe inlet; I can only measure pressure at the pipe outlet; ...
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2answers
38 views

Is the force exerted by the container on the fluid and the force exerted by the liquid on the container equal?

I came across a question where i was asked to find the force exerted by the walls of a frustum shaped bucket on a liquid inside it . I found the force exerted by the liquid on the walls of the bucket ...
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1answer
42 views

What happens to the level of water when ice containing stone melts? [closed]

What would happen to the level of water in a vessel, when ice containing a stone, melts? If there was no stone, the level of water will not change. But when the ice contains a stone inside it ...
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1answer
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Relation between Upthrust and Newtons Law [closed]

Using Newton's $2nd$ law of motion, show that when an object floats on the surface of water, the upthrust experienced by the object and the weight of object must be equal? The first thing is I don't ...
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Calculation of water pressure [closed]

I have a water tank of 750Ltr capacity installed at a height of 7.5M from ground. How to determine the range of pressure gauge required to measure the pressure from ground level.
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Fluid mechanics [closed]

While solving questions from the past years papers of iit jee i came across this question Two identical cylindrical vessels with their bases at the same level, each contain a liquid of density ...
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1answer
23 views

I need to know the pressure of gravity feed elevated water tank [closed]

I have a rain catchment tank holding 5,600 gallons of water 7 feet above the ground. I want to run this water 20 to 30 feet to drip water plants. Currently a hose runs to a computer valve (timer) ...
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1answer
32 views

Difference of water pressure

We know that $P = \rho gh$, so is it true that water pressure at 2nd floor will be higher than water pressure at 9th floor of a 12 story building?
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48 views

Melting of ice in beaker [closed]

If we have (i) ice with a stone frozen and (i) ice with a wood frozen . Both of these are kept in a beaker full of water . Then what will be the the change in water level in both cases when stone has ...
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1answer
39 views

What does Low Surface Tension mean?

I have that a book that says "Low surface tension of a liquid helps it to spread over a larger area." . My question is How and Why ? When I say that a liquid A has a lower surface tension than liquid ...
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What is the energy source if a tall water tank is used to transfer floating objects upwards instead of cables with motors?

Suppose I want to transport some logs from the ground to the roof of a tower. Originally I can use a lift, or some cables, or even move the logs upwards manually; then the energy is converted to the ...
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2answers
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Pressure change when closing valve inside a column of water

Main question: If you have a column of fluid with a valve as shown on the drawing, what happens to the pressure at the point p when moving from state A to state B ...
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7answers
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How to keep a helium balloon between 1 to 5 meters above ground? (without it being tied)

I understand that helium balloons rise because their density is less than air, so they can rise up to a point where the air surrounding it has the same weight as the balloon. I was thinking to fill it ...
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1answer
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why don't we consider atmospheric pressure or weight of liquid while deriving the equation of thrust in a fluid?

More specifically , when we try and prove that up thrust experienced by an liquid column inside the liquid is equal to the weight of the liquid column , I have seen it being derived like this: thrust ...
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2answers
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Is Buoyant force a reaction?

When we fall on water. The surface molecules are pushed down and as a consequence molecules below the surface molecules and molecules beneath them and so on are also pushed down. Some of them are ...
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1answer
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How does hydraulic press work at molecular level?

Let's consider the following arrangement: I know that because of conservation of energy the force on the car has to be amplified. The work $W$ done is $$W = \text{Force} \cdot \text{distance} \, ...
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Liquid pressure confusion

Water molecules are free to move around and they collide with the walls of the container in which they are kept.So,as a result they should exert pressure on the walls.But, while calculating force ...
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1answer
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Doubt in the concept of Upthrust and Buoyancy

First of all, we know that $P = hρg$ for any depth h in a liquid. While deriving this formula we use (mg + P1A) - P2A = 0, where P1 and P2 are pressures on the upper and lower surfaces respectively. ...
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2answers
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About the real reason why paper doesn't fall in HALF-FILLED inverted cup [duplicate]

I just happen to see a show about air pressure host by Brian Cox. As the link:http://imgur.com/EsRadFi shows, he flipped a half-filled water cup upside down then the paper on cup doesn't drop: It ...
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2answers
118 views

Why do helium balloons rise and fall?

I understand why a regular party balloon filled with helium falls over time due to leakage of the helium. However I've also noticed that recently filled helium balloons put outside rise and fall. At ...
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1answer
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Flotation of a body which is submersed into a incompressible fluid using Archimedes principal [duplicate]

There is a small boat in a water tank and the boat is loaded with a huge piece of rock .The water tank is totally filled with water .If the rock is taken off from the boat and totally submerged in the ...
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1answer
52 views

The Direction of Pressure Gradient in Hydrostatic Equilibrium

The equation for Hydrostatic Equlibrium in galaxies and galaxy clusters is quoted as: $$\frac{dP}{dr}\times\frac{1}{\rho} = -\frac{GM}{r^2}$$The minus sign on the right hand side indicates that the ...
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2answers
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Finding the work done to fill the tank by pumping water over the edge? [closed]

I am really confused on how to approach the following question and how to set it up. So the question is: An open tank has the shape of a frustrum of a right circular cone. The tank is ...
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3answers
562 views

How can the atmospheric pressure be different in distinct points at the same altitude?

From an hydrostatic point of view, the pressure in a fluid should be the same at the same depth/altitude. Obviously, in our atmosphere that does not happen. I am guessing that the main reason is the ...
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2answers
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Water bombing - risks and possibilities

I just saw a video on youtube, where an excavator drops a load of water on a car, destroying it completely. I also saw a video with a fire-fighting plane dropping even more water on a burning truck. I ...
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2answers
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Why buoyancy is applied on centroid?

My book says: "The point of application of the buoyancy force is the geometric center(centroid) of the submerged part of the body, whereas the specific gravity of the fluid is constant." But why ...
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1answer
133 views

Questions on Pascal's Principle

I am aware that Pascal's principle says that if a pressure acts on an enclosed liquid, the pressure will be transmitted uniformly throughout the liquid. Can Pascal's Principle be applied to a ...
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A pure water ice cube with sides 2cm long floats in a liquid in a glass beaker [duplicate]

A pure water ice cube with sides $2\,\mathrm{cm}$ long floats in a liquid in a glass beaker. What volume will be below the liquid surface if the liquid is a) pure water and b) brine? ...
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1answer
55 views

Could a big enough straw stretching from Earth to space eject atmosphere into space? [duplicate]

Assuming the straw can be built out of any material, shape, size. Would the vacuum effect of space acting on the pressurized gas have enough force to lift the weight of the atmosphere contained in ...
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2answers
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How come a cork float to the side of a glass? [duplicate]

There's a not-so-recent video by a user named quirkology here, where he shows bets that usually work. From @2:19, he puts a wine bottle cap at the center of a glass ...
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1answer
114 views

Would a pipe from the surface to the Earth's exosphere suck all atmosphere to the space? [closed]

If I built a tube from Earth's surface to the exosphere, would all the air be sucked out to space? If this pipe reached to a big planet, like Jupiter, would its gravity through the pipe suck our ...
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1answer
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What is the physical fundamentals of Pascal's law

Pascal's law or the principle of transmission of fluid-pressure (also Pascal's Principle) is a principle in fluid mechanics that states that pressure exerted anywhere in a confined incompressible ...
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1answer
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Fluid pressure when it is not vertically placed

The pressure of a point in a fluid is the sum of the external pressure and $pgh$. However, when the fluid is not placed perpendicular to the ground, then what is $h$ here? For example, a cup of water ...
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1answer
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Shape of water jet

Suppose you are shooting a water jet in a vacuum vertically onto a flat plate in a gravity-less room. The jet makes a right angle to the plate and water is assumed to be incompressible. The mass ...
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2answers
281 views

Proof of Archimedes Principle

Say I have an arbitrary body $\Omega$ and surface $\partial \Omega$ submerged in a hydrostatic fluid of density $\rho$ under the influence of gravity. How does one show Archimedes Principle? i.e. ...
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1answer
39 views

Effect on pressure for a decrease in temperature with respect to height

If I were to have a decrease in temperature with height, $T = f(z)$, I was wondering if I could calculate the pressure like so: Could I simply combine $$ \frac{dP}{dz} = -\rho g, $$ with the ideal ...
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1answer
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Hydrostatic forces in a bowl of cereal [duplicate]

This morning I was eating cereal which consisted of roughly spherical pieces just shy of one centimeter in diameter. By the time I was nearly finished, the cereal pieces were floating in a monolayer ...
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1answer
1k views

Will changing the pipe diameter reduce the pressure head loss?

I have this system installed in my house (fig 1), and I'm having problems with the shower. I want to know whether, if I change the PEX tubes shown in red from 1/2" to 1" as shown in fig 2, I will have ...
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9answers
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How to emulate 40ft (12 m) of water? [closed]

I am part of an underwater robotics team, and our next year's challenge requires us to compete at a depth of 40ft. We don't have any pools nearby to test in, so I want to emulate this 40ft of pressure ...
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4answers
1k views

Water pressure on a floodlight in a swimming pool [closed]

I have a circular swimming pool with a diameter of $4.5\;\text{m}$. The water height usually is about 1m. Somewhere in this pool is a single floodlight, circular aswell, diameter $25\;\text{cm}$. I ...
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1answer
100 views

Forces of suction in WIllie Wonka's Chocolate Factory (filmed 2005 starring Johnny Depp) [closed]

Before I begin the question: I am in no way judging this movie, just happened to be casually watching it and saw the scene (referred to below) and thought to post this question. The scene: Boy falls ...
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1answer
275 views

Determine water level difference in two ponds

I live near two ponds whose water levels appear to differ by a few feet. The ground is hard clay, so I don't think there's any underground water exchange between the ponds. The ponds are separated by ...
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Calculating rise in water surface due to a charged capacitor

Two metal plates separated by a distance d & initially charged with charge +Q & -Q are kept so that it just touches the surface of a very large water tank as shown in figure a. Thus water ...
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Meniscus attached to an inclined plate

To be more specific, suppose a hydrophilic infinite plate is stuck into a semi-infinite region of water, above the water is a semi-infinite region of air, when the plate is stuck into the water ...
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1answer
58 views

Does the contact angle of a drop depend theoretically on the size of the drop?

According to Wikipedia, contact angle depends on the hydrophobicity of the surface and on thermodynamic equilibrium. But how does it in theory depend on the drop size? In other words, how would a ...