Questions tagged [buoyancy]

Use "buoyancy" for any question where an object is suspended or submerged in a fluid. Buoyant force is the force that acts upward on a partially or completely submerged object.

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What will happen if 10kg massed hydrogen ballon is released in air?

Generally, a hydrogen balloon would float when released in air, but what will happen when that hydrogen balloon has a mass of 10kg. Is it the density that decides whether an object floats in air or ...
DrixxXo's user avatar
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4 answers
89 views

What is definition of weight?

What is definition of weight? Does weight of an object change under water, or the weight remains the same, but the: 'apparent weight' = 'weight' - 'buoyant force' ? Same question for object submerged ...
Cornelius's user avatar
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Would a candle in very high gravity blow itself out?

A candle creates an upward draft of hot air, without which the flame would be spherical. The buoyancy generated is proportional to the density difference as well as the strength of gravity. Suppose a ...
Kevin Kostlan's user avatar
-1 votes
2 answers
49 views

Adding mass to a bowl until it sinks [closed]

I've been struggling with this question. A hemispherical bowl of inner radius $r$, density $ϕ$ and thickness $t$ is floating in a fluid of density $ρ$. The bowl is being filled with sand at a constant ...
Developer's user avatar
1 vote
4 answers
63 views

Confusion regarding a wooden block floating in water in a sealed container [closed]

Consider the following situation in which a wooden block floats in water in a sealed container. When the container is at rest, $1/4^{th}$ of the block is above the water. Now, when the air pressure ...
Haider's user avatar
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-2 votes
3 answers
49 views

Buoyancy: True mass (2nd law of newton and density ratio) [closed]

How can I calculate the true mass of an object in a fluid (f.e. air)? Given: force measurement (F = 863000 N) air density (rhoA = 1,29 kg/m^3) object density (rhoO = 1100 kg/m^3) g (g = 9,807 m/s^2) ...
Sylvia's user avatar
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0 votes
2 answers
94 views

Does a object, that is partially submerged in a liquid, lose any weight?

I know that all objects, regardless of their density, feel buoyancy force. But do partially submerged, meaning an object that has lesser density than the liquid,lose weight. For example and object ...
safwan05's user avatar
10 votes
2 answers
463 views

Could a fish swim out of a sphere of water in a zero-gravity environment?

Can a fish swim out of a sphere of water in a zero-gravity environment? I am going to state some assumptions. We assume the sphere of water is not affected by any thermal properties of its zero-...
Jonathan L.'s user avatar
0 votes
0 answers
244 views

Experiment about a sphere in a tube in presence of viscous resistance

Recently, I carried out an experiment at home with little equipment, but I can't get to the bottom of it. Consider a fluid-dynamic resistance force of intensity $F_L$ ($\vec F_L = - \alpha \vec V$) ...
Bml's user avatar
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3 votes
3 answers
445 views

Conceptual misunderstanding in Buoyant forces [closed]

This is the problem:A piece of ice floats in a vessel with water above which a layer of a lighter oil is poured. How will the level of the interface (oil and water) change after the whole of ice melts?...
Hammock's user avatar
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1 vote
1 answer
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If an object suspended by a string is immersed in a liquid, will its weight contribute to the pressure at the bottom of the container?

We have a metal sphere completely immersed in a liquid of density A by means of a string. Since the sphere is exerted by the buoyant force due to the liquid the sphere must also exert an equal and ...
Nightwing 's user avatar
1 vote
2 answers
103 views

Archimedes' principle for gases

https://www.toppr.com/ask/question/archimedes-principle-does-not-apply-to-gases/ https://byjus.com/question-answer/archimedes-principle-cannot-be-applied-to-gases-true-false-1/ These two pages say ...
Apoorva Shukla's user avatar
0 votes
1 answer
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An ice cube containing a metallic ball in it is floating in a vessel containing water. When the ice melts, what happens to the level of water?

I understand the fact that if there was no metallic ball in it, then when the ice melts, the level of water would neither rise nor fall. Now let us consider the case where there is a metallic ball in ...
wonderingwhy's user avatar
2 votes
4 answers
484 views

Is buoyancy affected by container geometry? [duplicate]

Is it possible for something that can't float in a rectangular container to float in a triangular container?
Mason Valentine's user avatar
0 votes
2 answers
80 views

Confusion about the "Volume" in Archimedes principle

In Archimedes principle $F_b = \rho gV$. $\rho$ = density of fluid, $V$ = volume displaced by the fluid, and $g$ = gravity. If you have an object in the air, like a balloon, how does the volume work? ...
god david's user avatar
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0 answers
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Work Done by Buoy When Displaced by Wave

I have a cylindrical buoy with the flat parts on top and bottom respectively. The radius of the buoy is 3 mts. It's hit by a wave with an amplitude of 1.5 mts and a period of 7.3 sec. I want to know ...
Rodrigo Negrete's user avatar
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1 answer
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Buoyancy in the hydrostatic equation

I have a question regarding the fundamental equation of hydrostatic, namely: $\vec\nabla P=\rho \vec g$. Why do we not take into account in Newton's 2nd law (used to prove this equation) the buoyancy? ...
Arthur Filippi's user avatar
1 vote
1 answer
38 views

What is the effect of pressure differentials due to gravity on buoyancy force?

First of all, I am aware that this question has been answered in the past, however I have some follow up questions particularly regarded the argument posited in Why is Buoyant Force $V\rho g$? : When ...
darklyspaced's user avatar
-4 votes
1 answer
67 views

Could a perpetual motion machine be made using a filling buoyant object that sinks when filled and releases when bottoming out? [duplicate]

Could you make a perpetual motion machine via buoyancy? If you started with 2 types of fluids with different buoyancy. Then add a buoyant object capable of filling with the top fluid where it closes ...
Jans Mcclain's user avatar
7 votes
4 answers
2k views

How can the weight of a container be affected by an object's buoyancy?

Suppose a table tennis ball is immersed in a fluid and held down by a string. The container is placed on a scales. What will happen to the reading of the scales if the string breaks? How can you ...
Yitian Chen's user avatar
-6 votes
1 answer
106 views

Was the Michelson & Morely experiment ever valid? [closed]

One of the key predecessors to Einstein's Relativity was another theory having to do with an "Aether" material. This substance was supposed to be the substrate that the universe is built ...
david.cowan's user avatar
1 vote
1 answer
75 views

Potential energy of a gas lighter than air

Here is the situation. Let's say I have have a mass of a given liquid and I heat it to create a gas. The gas has a lower density than air, so it will move higher and higer in the atmosphere. Then, I ...
benjamichon's user avatar
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0 answers
29 views

How much salinity is needed for everyone to float?

Everyone floats in Dead Sea because it is so salty. Is it true in Great Salt Lake? How about Red Sea and Mediterranean Sea? Is it impossible for anyone to sink in these seas without added weight?
Michael Tsang's user avatar
0 votes
2 answers
118 views

What is the Buoyant force experienced by a cube at a certain level inside water?

I'm not able to comprehend the meaning of buoyant force. As per Archimedes Principle, it's the force equal to the weight of the volume of water displaced by the body. But wouldn't this be only true ...
Aryan's user avatar
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2 answers
181 views

Does buoyancy force depend on the acceleration of the buoyant object?

According to Archimedes' principle, the buoyancy force on a submerged object is given by the product of the mass of the displace fluid and the gravitational acceleration. Effectively, it is determined ...
Thomas's user avatar
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2 answers
103 views

How does a static fluid exert pressure in upward direction? [duplicate]

I was going through the derivation of a mathematical equation for the upthrust exerted on a body which is given in my book. It says that the downward pressure exerted on the upper surface is less than ...
user avatar
0 votes
1 answer
65 views

Why are there 2 ways of predicting if an object will float or not?

I thought about it for a second, I have always thought that for an object to float it had to be less dense than water, and if it had more density then it would sink. But then if it sinks or floats ...
Alysid's user avatar
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0 votes
2 answers
81 views

According to an equation I derived, an object with negligible height would always sink. Where is it flawed?

Assume that an object has negligible height, i.e., height is approximately $0m$. If we immerse this object in water, will it float or sink? In order to find this out, we need to calculate the net ...
Ishaan Manish's user avatar
0 votes
2 answers
55 views

Buoyancy with Object of Heterogeneous Density [closed]

The Archimedes buoyancy principle usually seems to be taken for objects of homogeneous density. So for example a sphere would have mass equal to $(4/3) \pi r^3 \rho$, where $\rho$ is the density. ...
Tom's user avatar
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How does the hydrostatic paradox operate when a column of lighter liquid rests atop a “floor” of heavier liquid?

I know that, according to the hydrostatic paradox, the height of a homogeneous liquid is the only determinant of pressure within that homogeneous liquid, and the shape of its container does not affect ...
Russell's user avatar
4 votes
4 answers
341 views

Is the buoyant force on an object a kind of normal force?

So, simple question, are the bouyant force applied to an object by a fluid and normal force (Is it even there?) related? If no where is the normal force and why does bouyancy even happen?
Shivang Thakur's user avatar
1 vote
0 answers
98 views

Is there a depth under which the buoyant force is no longer sufficient to bring a diver back to the surface? [duplicate]

I came across the story of diver Yuri Lipski who died while diving in the Blue Hole. This made me wonder something and it may be a stupid question but I thought I'd ask: For a human diver with normal ...
Fermin C's user avatar
0 votes
1 answer
44 views

Sealed container with half-open gas buoy

Consider a sufficiently rigid and sealed container completely filled with liquid (e.g. water), pressurized at 1 bar, at constant temperature. Inside the container there is a buoy partially filled with ...
PSz's user avatar
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10 votes
2 answers
4k views

Is it correct to say that "WE" feel only 5/140 of the actual weight of brain as buoyancy acts on brain due to cerebrospinal fluid?

Many sources of biological sciences (e.g.https://medium.com/@drvnx/what-is-that-thing-without-which-we-are-dead-f556fb1029ef ) say that the actual weight of brain is almost 1400gwt but as brain ...
Shinnaaan's user avatar
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0 votes
0 answers
18 views

Will the water level change due to releasing a ironic ball from a floating ice cube? [duplicate]

A piece of ice is floating in a glass of water. There is a small ironic ball inside the piece of ice. If the ice completely melts, the ball will be released into the water. Then will there be any ...
Ibteeker Mahir Isham's user avatar
2 votes
2 answers
148 views

How to derive the formula of the buoyant force?

I've seen some variations of this question on the forum, but none has satisfactorily cleared up my confusion, so I made this post with information about what I take issue with specifically. Thank you! ...
ten_to_tenth's user avatar
1 vote
3 answers
199 views

Buoyancy force vs object weight

If an object is floating (partially or fully), does the buoyancy force = the weight of the entire object? My confusion is, situation A: 100g object is 50% submerged and floating situation B: 100g ...
mar01's user avatar
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13 votes
5 answers
2k views

How does inertia affect an object suspended in a fluid?

When I asked my physics teacher how fully submerged objects are suspended in fluids, she told me it was because the object's density was equal to that of the fluid's as a result of the net force ...
FishFlops's user avatar
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0 votes
3 answers
79 views

Feeling of coldness in heights

We know that due to buoyancy the cold air sinks and warm air floats above it due to it being less dense than cold air. Then why do we feel cold as we go to greater heights/hill stations and feel hot ...
Naveen V's user avatar
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2 votes
2 answers
352 views

Why do some objects tend to sink after some time in water even if they float at the start?

I have observed this phenomenon in swimming pools: I have seen many dead insects floating on the surface, but after some time some they tend to sink down without any external influence. Why does this ...
Naveen V's user avatar
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0 votes
2 answers
93 views

About the floatation of bodies on a surface

A body which is partially floating in water is in equilibrium due to the balancing of the buoyant force and the weight of the body. Now what will happen to a body floating on the surface of the liquid ...
TheCuriousOne's user avatar
1 vote
0 answers
37 views

Buoyancy, mechanic of fluids hydrostatics

I am struggling to understand how to solve buoyancy problems, and I have one that would help clarify my mind if you could help me, please. There is a tank with depth H and a plug at the bottom of the ...
Lourdes 's user avatar
-1 votes
1 answer
54 views

How does buoyant force formula work if it got nothing to doi with the dencity of the object?

Google tell me the formula for buoyant force is Fb = -pgV Where Fb is buoyant force and p is fuid dencity , g is gravity index, V is fuid volume which I suppose is just like the volume of the object. ...
james.yi's user avatar
6 votes
1 answer
891 views

If fluids exert force in all directions then why do objects float? [duplicate]

My question is that when we place a body in water it exerts a buoyant force but it exerts an equal force in downward direction then why its buoyant force is greater and the object floats?
spider078's user avatar
1 vote
1 answer
80 views

Why doesn't this buoyant free energy device work?

Okay so I've seen a few of these but the setup here is a bit different. Suppose we set up an electrolysis plant at the bottom of the ocean and for some constant energy cost $E_1$, we can get a bunch ...
Kelvin's user avatar
  • 111
0 votes
2 answers
92 views

Confusion regarding direction of buoyant force

In this question, we are given the density of oil, water and the block. We are given that the block is floating, and thus we need to find what fraction of the block's volume lies in the oil. I have a ...
AVS's user avatar
  • 314
0 votes
2 answers
203 views

Why wouldn't this perpetual motion machine based on Archimede's principle work? [duplicate]

I found this today on the interwebs: Obviously this cannot work, but what bugs me is that I cannot figure out the part that would stop it and bring it to equilibrium. I suspect that it has to do ...
Vilx-'s user avatar
  • 3,071
0 votes
3 answers
522 views

Why is an object considered less buoyant if it is fully submerged? [closed]

I found the following on BYJUS: A body experiences greater buoyant force when it is fully submerged compared to when it is partially. https://byjus.com/question-answer/a-body-experiences-greater-...
Sophie Lee's user avatar
0 votes
0 answers
44 views

Buoyancy force | What is the correct way to describe and explain Buoyancy force at a macroscopic but also a microscopic perspective

Have you ever noticed objects going down in a pool, reaching equilibrium? Often, when a submerged object (and in contact to the floor) is moved, it start going up again. Why? This kind of scenarios ...
nuwe's user avatar
  • 254
0 votes
1 answer
119 views

Deriving Formula for Archimedes' Principle [duplicate]

Let B be the buoyant force acting on an object and W be the weight of the fluid it displaces. I can't derive the formula for Archimedes' Principle: B = -W I have found plenty of derivations for B = W ...
Anis Manuchehri-Ramirez's user avatar

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