Questions tagged [fluid-statics]

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What is buoyancy?

I’ve seen answers which cite newton’s third law as the cause for buoyant force, but wouldn’t this mean the moment an object of any weight is placed on a fluid, the fluid would immediately exert an ...
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Can density replace buoyancy?

Recently I discussed the possibility of a flat earth, with a flat earther whom rejected much of established science, especially newton and his laws because Newton's idea of gravity rendered a flat ...
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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 ...
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Does the pressure from a water tank increases as the altitude increases?

If a solenoid valve is placed right after water tank's water tap does the water pressure changes if the water tank is lifted to 3 meters? The context is this: the electric valve is functional only if ...
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A balloon starts rising upwards with constant [closed]

So i was doing this illustration when I looked up the solution given below it I got confused at a certain point . Everywhere the acceleration $a$ of the balloon is taken into consideration so where ...
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2answers
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Does the mass of a beaker filled with water change due to a mass partially submerged in it?

I believe it should be different as there is upthrust acting on the second block and hence by Newton Third's Law it should act back on the liquid adding to more weight. The answer is given isn't so as ...
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2answers
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Young's equation

Can somebody derive the Young's equation for the contact angle and surface energy of a droplet. $$\gamma_{la}Cos\theta+\gamma_{ls}+\gamma_{sa}$$ I've scratched my head for days finding how it exist....
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mimium force so that given ballon will not burst

yesterday our physics teacher taught us about fluid and its properties.and explain us that fluid is always ready to travel from high pressure zone to low pressure zone .a question struck in mind ...
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In fluids, what is the difference between the two forces in the formula $F=pA$ and $F=\rho Vg$?

I was doing a question on fluids which is: A living room has floor dimensions of $3.5 m$ and $4.2 m$ and a height of $2.4 m$. What does the air in the room weigh when the air pressure is $1.0 atm$?...
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1answer
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Pressure and upthrust force

What is upthrust force? Is is the pressure difference or just pressure x Area at the bottom of the surface? How does upthrust force change with depth in liquid?
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1answer
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Temperature relation to Archimedes principle

I have a probably very simple problem which I cant solve. I am weighing animals in seawater by placing them on a small PVC arm that is fixed on a balance and reaches into a beaker of seawater. On the ...
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1answer
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Barometer-an air pressure measuring device

I have read about torricelli's invention of barometer,in that he used a test tube which he filled it fully with water and also he take a container and filled that container with some water.Now he ...
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Does a rubber pipe bears more weight when the pressure of water inside it is high?

I have passed a rubber pipe across a road to my home temporarily. The pressure of water inside the pipe is very high, the vehicles and school buses passes over it! i am interested to know that "In ...
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Why does a helium balloon rise? [duplicate]

This may be silly question, but why does a helium ballon rise? I know it rises because helium is less dense than air. But what about the material of the ballon. It is made up of rubber/latex which is ...
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1answer
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Acceleration acquired by a metallic ball in a fluid [closed]

A metallic ball of density $4.9gcm^{-3}$ is thrown in a bucket full of water.What is the acceleration acquired by the ball?(ignore all factors except gravity and resistance given by water,ball and ...
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1answer
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What makes that thing so bouncy? OOO

Lets take a small coke bottle(plastic one). Now fill the bottle entirely with water not even letting a small air bubble, however a tiny bubble always form. Now this water bottle when dropped will ...
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Transfer of gas particles during pressure change

There is a room with a known volume. The temperature and pressure are known too (STP). It is given that the window is open and there will be a pressure drop outside due to wind. I need to find the ...
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1answer
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Mercury Barometer

Why Mercury surface is flat instead of convex at 760mm Hg level in Mercury Barometer? refer the image attached. note that At top it is a vacuum and surface tension = (pi-po)r/2.
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2answers
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What makes an ideal liquid incompressible?

Just thinking about liquids and Pascal's law when, this question came. Ideal liquids, I understand, are deemed to be incompressible, which simplifies our problems while decently holding good for some ...
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Fast reversible switching from hydrophobic(>120 degrees) to hydrophilic (<60 degrees)?

I found few papers on reversible switching from hydrophobic to hydrophilic Reversible Hydrophobic to Hydrophilic Transition in Graphene via Water Splitting Induced by UV Irradiation Light-induced ...
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0answers
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Confusion about the coefficient of surface tension and the relation between force and length of a body

I haven't found a software that can create 3d or 2d shapes filled with liquids so I posted this picture. I know that the p=2σ/r where p is the pressure that goes inside the liquid and I guess that σ ...
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0answers
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Density of different liquids in manometer

According to diagram, liquid X and liquid Y have the same pressure on mercury, but how can I know which of them will be denser, liquid X is denser than liquid Y or reverse argument?
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Is this working by communicating vessels?

https://www.youtube.com/watch?v=JzuamK0AyC4 I think the first 2 bottles are working by communicating vessels because i think that the third bottle is with atmospheric pressure and since the second ...
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1answer
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Diameter to prevent water flow into a closed-end tube?

Imagine I drill three holes of different diameter into a large block of plastic but the holes don't go all the way through. (They form three close-ended tubes, see the image.) I then submerge the ...
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4answers
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Does a non-buoyant (denser than water) object (such as a lead diving weight) weigh any less when submerged in water?

I've just been discussing this question with my eldest son, who is an extremely intelligent man, as well as being an engineer, a sailor and a scuba-diver, and he believes that an object heavier than ...
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1answer
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Block completely immersed inside the fluid

Consider a block with density $\sigma$ kept in liquid of density $\rho$, where $ \rho > \sigma$. Now what is the cause of force by which it moves upwards? Is it buoyant force? If yes, then how? As ...
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1answer
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Bubbles in a Pipeline 2

This question has kind of been asked before here, but aren't the gas bubbles in the pipeline also a moving fluid and so as they get constricted shouldn't their pressure decrease too. If so how are ...
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1answer
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What is the pressure of water after entering atmosphere? [closed]

I was wondering if water exits from the pump and reach the ground, is the pressure of the water at the point of the ground be 0?
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1answer
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Atmospheric pressure in a closed container

it's my first post here but I just have a quick question regarding my fluid mechanics assignment. There's an inverted manometer setup like in the photo which is a closed system. It's given me ...
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3answers
68 views

Will buoyancy act on B? [duplicate]

A is immersed in water, buoyancy must act on A; B is at the bottom of the container, there is no water between B and the container, that is to say, the bottom of B is not in contact with water, so ...
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1answer
41 views

Hydrostatic pressure to measure water level

I am measuring water level in a 25-inch tall vase using hydrostatic pressure. Like this. To do this I have a 1/4 OD inch nylon tube connected to a gauge pressure transducer. So far it has been very ...
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1answer
53 views

Will a piece of ice, floating on water in a beaker, rise or fall when I add oil on top of water? [duplicate]

There is a beaker of water with ice floating on top of it. If I add oil (lighter than water and ice) to it such that it forms a layer above water and ice is suspended between those layers. Does the ...
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forces in free liquid surfaces

why the answer does not take into account the area of ​​the sides of the triangle?(F=PA) the vectors on the right side of the triangle what do they indicate? the pressure is not even a vector the ...
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0answers
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Easy derivation of Pascal's Law

I would like to know a simple derivation of Pascal's Law, i.e. why the variation of pressure at a given point of an incompressible fluid also happens to all others.
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1answer
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Size of a raindrop

Thinking about the fact that raindrops come with a typical size I was wondering how this can be determined. I am pretty sure that the friction with air and the quantity of water in the clouds are ...
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1answer
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How does surface tension cause glass plates to attract?

I am having trouble with this example : As it says that the contact angle of the glass water interface is $0^{\circ}$ , so the force due to surface tension should act downward on the plates (rather ...
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1answer
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Effect of increased air pressure on water pressure in sealed container

Imagine I have a plastic bottle filled most of the way with water and with a bicycle pump attached to the top without any leaks... If I increased the air pressure in the top of the bottle to, say, 30 ...
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1answer
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Contact angle of a thin film problem

I am having a hard time with problem 8 , so can anyone give me some hints. I'll say the things I have in mind I can use the Laplace pressure difference equation to find the the excess inside pressure....
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1answer
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Can a pressure wave induce pressure in a liquid it's propagating through?

I have a piece of cylindrical plastic container containing a liquid and sealed at all ends. The bottom seal is a flexible material that can be broken with enough force. The question is then is: can I ...
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Hydrostatic pressure

The solvent in which porous structure will create higher hydrostatic pressure at the beginning of the solvent removal process? I have two porous cakes, A and B with different height. A is 9.6 cm and B ...
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1answer
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Height of fluid and pressure

It’s a well known fact that pressure at bottom of the contain depends on height of the fluid column above it. If I add a ultra thin capillary tube as a fifth tube, then height of the water column ...
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5answers
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Does Archimedes principle account for depth?

The principle states that the upthrust acting on an object is equal to the weight of the fluid displaced by the object. However, this to me suggests that no matter how deep an object is immersed in ...
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0answers
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How does Bullheading work?

Bullheading, a method of Well Kill, involves simply pumping the kill fluid (heavy fluid) directly down the well bore forcing the well bore fluids back into the reservoir, does the heavier fluid flip ...
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0answers
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Does tilting a liquid develop shear stress on its surfaces?

Please help me these confusions I have. If I tilt a cuboidal container containing an ideal fluid (non viscous liquid), does a shear stress develop on the liquid due to some shearing force acting ...
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Does angle of contact remain constant for rise of liquid in a tube of insufficient length?

My book states that for rise of liquid in a capillary tube of insufficient length h * R (radius of curvature) = constant. Since the tube is of insufficient height radius of curvature increases to ...
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1answer
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Force on the base of a container

There are 3 containers ,having the same base area ,having being filled with the liquid of same density to the same volume as shown in the figure. What will be the force exerted on the base in each ...
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5answers
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If atmospheric pressure is 76 cm of $\text{Hg}$ , why won't 76 cm of mercury stay in an open tube when suspended in air?

If we keep an hold a tube in air with the closed end up and open end downwards, containing mercury upto a length of 76 cm, why does the mercury not stay in place? Shouldn't atmospheric pressure exert ...
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1answer
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What is the minimum amount of matter do I need to call it “bulk” matter?

I had been reading about bulk properties, but was confused what should the minimum amount of matter be for these properties to hold. For eg: Intensive thermodynamic variables will not remain ...
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1answer
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Normal force on a fluid container [closed]

I was solving some problems and came across the following situation. Consider a container with one cylinder on top of the other. Area of cross section is $2A$ and $A$ for the bottom and top cylinder ...
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Hydrostatic forces of water spilling over gravity wall with slant sides

I want to calculate the horizontal and vertical components of hydrostatic forces on section of the dam. I understand that the force of water on the upstream surface is the same as when the side is ...