# Tagged Questions

Force per unit area.

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### Law of Floatation [duplicate]

We know, law of Floatation states that A body floats in a liquid if it can displace the liquid equal to its weight. But how can we derive this mathematically. Can anyone help me for this; Derive ...
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### The effect of surface area on the pressure exerted by gases

In a video about the relation between pressure and volume on Khanacademy, Sal says that on increase in volume the particles hit the wall less often because the volume has increased and the surface ...
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### find the density of water only by its pressure?

Is it possible to find the density or specific volume of water, by only knowing its pressure? Or we need to know its temperature as well? I can't find any relevant table, so can you advise me please? ...
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### Why does paper explode when compressed?

Various videos online show paper/card suddenly releasing energy in an explosion like way and transforming into a brittle material when put under sufficient pressure from presses. Examples are shown ...
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### Why does a band of paper I hold between my hands never breaks in the middle?

If I hold a band of paper with my digits and thumbs and start to pull, the band never breaks in the middle, but on one of the sides where I've put my fingers. Why is this? Has it to do with the ...
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### Pressure exerted by a gas and the ideal gas equation

While determining the pressure exerted by any gas at a temperature why do we not consider the surface area of the container in which it is kept? We say that : P=nRT/V, where, n is the no. of moles, R ...
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### Heating of mixture of gases with one gas barely above its boiling point

What happens when mixture of two gases is heated in a closed container? If one gas expands faster than the other and increases pressure of the container enough so that the boiling point of the other ...
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### Gas pressure within containers [closed]

If, hypothetically, a gas had no inner pressure, and it was made to fill up a container. If, then, the pressure within the container was increased by filling it up with yet more gas, until high ...
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### Can you pressurize a vessel to ambient pressure if the outside pressure is 0 psi?

let's say we have a vessel that is open to the atmosphere and is located at an altitude where the atmospheric pressure is about 0 psi. Then, we hook up a pressure pump and attempt to bring the ...
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### Application of Bernoulli's equation to siphon

I'm trying to understand how to use Bernoulli's equation in practice. So I will make an example of where is my confusion. I found this great explanation on Wikipedia about the siphon, but there is a ...
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I often read that when you have a deep cut on your arm, you should raise your arm to the point where the cut is above your heart. This should reduce the amount of blood loss because less blood reaches ...
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### Pressure Drop in Water Fountains

In first grade, my class made a list of things that our school could improve on. One of the things on the list was to increase the water pressure in the drinking fountains because it was very poor and ...
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### Pressure standing wave nodes at the end of the open side of a tube

I do not understand why standing sound waves can be formed in a one-side or two-side open tube. Consider a one-side open tube. In particular how does the reflection of the wave at the open end occur? ...
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### What happens if a cylinder filled with propane gas is connected to an empty one of the same size

Lets say I have 2 100lb propane cylinders. One of the cylinders is filled to its maximum capacity while the other is empty. If I connect them to each other via a high pressure hose in an upright ...
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### Why do liquids exert pressure on the sides of a container?

What makes a liquid push against the walls of a container if the liquid is completely static? I was thinking a comparable situation would be a bin full of baseballs. Unless the balls were perfectly ...
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### Force on a balls shell

Suppose we have a sphere with radius $r$ and the thickness of its shell is $l$. The pressure outside is equal to pressure inside which is $p$. Total force on the outside is: $F_o=pA_o=p4\pi (r+l)^2$ ...
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### Approximating the pressure drop for a centrifugal fan/blower

Is it possible to approximate the pressure drop for a centrifugal fan by using the fan's characteristics, the airflow, and the speed at which the fluid is being ejected? Would it be possible to adapt ...
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### Rankine Cycle Reheat Mass Flow Rate

Having worked through many examples on the rankine cycle both non-reheat and reheat, i just have one question. Can the mass flow rate of steam be calculated given only the data below? Boiler ...
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### If an unsealed water bottle has three holes at a different heights, why would the lower hole give out the most water? Is it because of air pressure?

If an unsealed water bottle has three holes at a different heights, why would the lower hole give out the most water? Is it because of air pressure? I am guessing it's because air pressure pushed on ...
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### Do you need to increase pressure to pump a fluid from a large pipe through a small pipe?

The application of this question is towards clogged arteries and blood flow. I am wondering why people with clogged arteries have high blood pressure if a smaller artery (assuming it is smooth and ...
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### Thermofluid mechanics, calculating load on a steel water tank

An open cylindrical water tank 2.4m diameter rests on three legs evenly positioned around the periphery of its circular base. The base and sides of the tank are made from steel with relative density 7....
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### Submerged water jet

I am trying to calculate at what pressure and speed water from a high pressure water jet will hit an object 100 millimeters away from the nozzle opening, but i can't figure it out. The nozzle will ...
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### Atmospheric pressure changes on plastic bottle containing a liquid

We have a problem at work and I need some help on a theory. We ship a liquid in plastic bottles using a pump closure. Recently some of the bottles have been arriving to customers having leaked. The ...
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### Bernoulli principle and falling object

Consider the following situation, also depicted in the picture bellow (and please excuse my lack of Paint skills): A helicopter is flying at a constante altitude, and hovering the same ground spot. ...
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### Why does the lack of pressure in outer space affect what's inside our bodies?

I have read multiple similar questions on this site, but none answer specifically the thing I am having trouble understanding. I have read repeatedly that a lack of pressure will cause the fluids ...
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### Rarefaction/compression events detection using time resolved sound measurement

I had a question about sound measurement in air using a B&K condenser microphone. In the acquired time resolved sound measurement signal I can see both negative and positive voltages/ pressure ...
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### Air preasure vs temperature [closed]

Suppose you have a container of 1 liter of air at sea level with an initial pressure of 1 atmosphere. How high could the pressure get by only raising the temperature. Is there a point (providing the ...
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### Refrigeration copper tubing

Recently I have seen few kinks and dents in the copper tubing refrigeration line of my air conditioner.Could anyone give a possible reason for this.
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### Phase diagrams and critical pressure

If a solid substance is pressurized past its critical pressure, what happens? Is the critical pressure only a factor when a substance is over the critical temperature also? On another note what makes ...
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### Why does an ideal gas not consist of identical molecules? [closed]

since the mass , temperature , and number of particles are the same , shouldn't the molecules be the same so that the pressure of the gad is inversely proportional to the volume.