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Questions tagged [pressure]

This tag is for questions relating to pressure, in the physical sciences, the perpendicular force per unit area, or the stress at a point within a confined fluid.

The amount of force exerted (thrust) on a surface per unit area is defined as ‘Pressure’.

The basic formula for pressure is $$P=\frac{F}{A}\qquad \text{i.e., (Force $(F)$ per unit area $(A)$)}~.$$

The SI unit is ‘pascals (Pa)’. $~1~$ Pa$~ = 1~$N/m$^2$

Types of Pressures are Absolute, Atmospheric, Differential, and Gauge Pressure.

3635 questions
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Pool in a submarine

A common theme in aquatic science fiction is the submarine pool/access to the ocean. That terrible TV show Seaquest had it, The Deep & Deep Blue Sea (Samuel L Jackson is standing in front of it when the shark chomps him). My question is how this…
George R
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Why does the aorta spray blood when atmospheric pressure is higher than blood pressure?

Atmospherical pressure is around 760 mmHg, while blood pressure is on average 100 mmHg. Then why do you bleed from cuts, and why does a cut aorta spray blood? The atmosphere should press the blood back in, or at least stop it from spraying.
Karin
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Why does a gas inside a closed container experience atmosperic pressure when the gas itself is not in contact with the atmosphere?

I know this is a very basic (and probably stupid) question, but I have been confused about this for a long time.
Edward Stumperd
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What is the meaning of pressure of a gas

I understand the meaning of pressure on a surface to be force acting per unit area. But when it comes to understanding pressure in the context of fluids in motion or at rest I think I am having some trouble grasping the concept. When we say the…
smilingbuddha
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Why does a tail of a balloon poodle not collapse?

I was just wondering. How can it not collapse? There is pressure in the tail top and in tail itself. How can that little "bridge" (with that I mean the part that in not inflated, see image 2) and tail top sustain and not collapse? 1. Image of…
SjonTeflon
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How does a plunger (toilet plunger) work?

I don't quite understand the physic involved in operating a plunger. I thought that using a plunger on a clogged sink, for example, would create a difference in pressure inside the tube so that, after releasing the plunger, the "force of the air…
Geeo
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Why don't we include $\rho g h$ in a hydraulic jack below?

Consider a hydraulic jack with massless pistons as follows. The famous equation for this system is $$ \frac{F_1}{A_1}=\frac{F_2}{A_2} $$ My question is why isn't the equation as follows? $$ \frac{F_1}{A_1}=\frac{F_2}{A_2} + \rho g h $$ It is based…
kiss my armpit
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why is the force on the side of a very narrow tank independent of the volume of water?

I building a tank for water 2ft high, 2ft wide (front to back), 8 feet long (left to right) Common formulas dictate the total force on the long sides is approx 1000lbs (w x h x .43). Where .43 is psi per foot of depth and average psi is at depth 1…
user2624395
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How deep in the ocean can a ping-pong ball go before it collapses due to pressure?

Stimulated by the calculation showing that a ping-pong ball does not pop in vacuum, I'm driven to ask how deep in the ocean a ping-pong ball can be brought before it collapses due to pressure. This has a practical application in that boats have been…
Carl Brannen
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What does the pressure-position graph look like when an upside-down mug with air is pushed underwater?

I know that the pressure increases linearly between A and B, once the mug is at B there will be a jump in pressure, and then the pressure will be constant between B and C. I'm just not sure if this sudden jump in pressure is increasing or…
John
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Why doesn't soda fizz at high pressure?

In this video, a can of soda is opened in an underwater station at 2.5 atm. The demonstration is that shaking the soda doesn't cause it to explode like it would at normal pressures. Why does this work? Is it because the pressure inside the soda can…
Kris Harper
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Does gauge pressure or absolute pressure define tire characteristics?

Recently had new tires installed on my vehicle, and checked the tire pressure. I found that tire gauges read about 3 PSI higher than the TPMS system in the vehicle. I did some more research, and found that this is because TPMS system in the vehicle…
Justin H
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Should a soda bottle be squished before being stored?

A friend explained to me that to prevent an opened soda bottle from going flat, the best course of action is to press the bottle before putting the cap back on as to chase air out of the bottle. This seems counter-intuitive to me, since this should…
usernumber
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What happens to the vapor pressure when I expel the liquid phase from the vessel?

Suppose I put water in a closed vessel and heat it, so the vessel becomes pressurized above ambient pressure. Now, there should be liquid and gaseous water inside the vessel. Since it's under pressure, when I open the vessel at the bottom, the…
Hanno Fietz
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How to optimize apple pressing

This is how the press works: (I'm sorry if it looks like a Pokeball, but I'm proud of my paint) This is a top view. The black part is the container, it is a hollow cylinder. In the middle (in dark blue), there is the bladder. It's made of rubber…
Urefeu
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