Force per unit area.

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-2
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0answers
30 views

Gas diffusion (book request)?

I want to know the permeation conductivity K of air/Steel and air/Aluminium and I could not find it in internet!! Does anyone know where to find such information (books,articles..etc.) ? $$ Q = {kA\...
4
votes
1answer
50 views

Does the force on the bottom piece of a hummingbird feeder depend on the height of the water in the reservoir?

Intuitively I would think that the more nectar you put into the reservoir the more weight it will put on the bottom piece (the tray that holds the open pool of nectar that the birds can feed out of). ...
-1
votes
1answer
16 views

Calculate amount of gas flowing in a pipe [on hold]

I have two tanks of a gas which are connected to two different pipes and supplied to two different furnaces. I need to keep a check as to what is the quantity of gas (in KG) that is consumed at any ...
-1
votes
0answers
13 views

Water Mist Problem? [on hold]

If a 150 USGPM 20 deg.C water in a 40 mm diameter with pressure of 25 bar need to be reduced to 2.5 bar through an orifice: will the water mist manifest?
0
votes
0answers
35 views

I'm confused in this dilemma about pressure [on hold]

Bernoulli principle ensures that when cross-sectional area is small the velocity will increase and so the pressure decrease. So, in a pump the outlet hose area controls the pressure and velocity of ...
2
votes
2answers
37 views

Spring behaviour under high atmospheric pressure

We have a spring inside a chamber. We compress the spring and then let it decompress freely. Will its decompression (its speed and displacement) be the same if the air pressure of the chamber is $1\;\...
0
votes
0answers
21 views

Bottles Leaking Due to Air Pressure [closed]

Is it possible for essential oils to leak from bottles, that have been sealed, whilst in an airplane due to air pressure? Thank you kindly. SJ
-1
votes
2answers
65 views

What happens to gold under immense pressure? [closed]

What would happen to gold if you put it under immense atmospheric pressures? For example 2M atmospheres.
0
votes
0answers
24 views

How would I go about calculating the frequency and amplitude of a sound produced by a collision?

How would I go about calculating the sound pressure level, frequency and amplitude of a sound caused by a collision, given the velocities of the two objects colliding, their acceleration, densities, ...
6
votes
4answers
141 views

Will a tennis ball go further if i hit it with the side of the racket?

If i hit a tennis ball 'properly' on the stringing, does it go further than if i rotate the racket 90 degrees in my hand and hit the ball with the same force, but on the side of the frame? I'm ...
-1
votes
0answers
8 views

Pressure factor affecting reversibility of a process [duplicate]

It is said that for a finite pressure difference between system and the surrounding the process is irreversible. From the diagram can you please tell me how the process is irreversible ? Does this ...
0
votes
2answers
32 views

Pressure in deodorant can

Pressure in a deodorant can is greater than the surrounding pressure but still the can is in equilibrium with the surrounding . Why does this happen. If we apply $F = PA$ then $P_{in}A= P_{atm}A$ and ...
7
votes
3answers
98 views
+150

Fluids with critical point at ordinary temperature and pressure

Are there any fluids with critical point near STP or that are supercritical at STP? If not would it be feasible to design a molecule for a substance with critical point near STP using theoretical/...
1
vote
1answer
39 views

How to find weight of compressed air?

Lets say I have an aluminum canister with an interior volume of $V$ cubic feet (under normal circumstances and pressure, that's how much air it can hold). If I pressurize the canister to $x$ psi, the ...
4
votes
0answers
37 views

Parabola or Catenary in this case?

Exhibit A: the flexible film sinks into the box due to lower internal pressure inside the box. question is, does the film form a paraboloid or a 3D catenary or neither? this is the usual method used ...
-1
votes
2answers
45 views

Pressure Difference affecting reversibility of a process

It is said that for a finite pressuredifference between system and the surrounding the process is irreversible. From the diagram can you please tell me how the process is irreversible ? Does this ...
0
votes
1answer
36 views

Is there a thermodynamical function $\Xi$ such that $d \Xi = V d P/H$?

Question Is there a thermodynamical function $\Xi$ such that generally $$d \Xi = \frac{V d P}{H}$$ where $V$ is the volume, $P$ the pressure, and H the enthalpy $H=U + PV$? If such a function ...
0
votes
4answers
104 views

Why don't high pressure gases stored in containers lose energy?

Containers holding gas at a high pressure don't slowly lose the internal energy of the gas. It seems like the high speed particles would collide with the metal walls and slowly transfer their energy ...
3
votes
3answers
59 views

Is there a prohibited region in $P-V$ plane?

Polytropic process generalize the particular thermodynamic processes with $$P V^{n}= \mathrm{constant}$$ Where, if $n$ changes, the curve on $P-V$ plane changes, as shown in the diagram. The orange ...
5
votes
2answers
119 views

Why does saliva on the finger give correct direction of wind?

When we lick a finger and put it up in the air, the side that is cooled is the one facing the direction from which the wind is blowing. But consider this, if we take a cross section of the finger, ie ...
0
votes
3answers
65 views

Oscillations in U-tube [duplicate]

U-tube, of uniform cross section $S$ and opened at both ends, is filled with a liquid column of length $L$ and density $\rho$. In equilibrium the water levels in both arms are at same height. What ...
0
votes
1answer
25 views

How does atmospheric pressure affect the speed of object?

I was reading things about the Hyperloop One start-up project ( https://hyperloop-one.com/what-is-hyperloop) and I couldn't get any details on how the process works. This is a new transportation type ...
0
votes
0answers
42 views

Wind Flow Simuation Equation

I have a data that contains pressure measurements in difference locations. Now i want to do wind flow simulation based on the pressure difference between these places. The problem is i want to do this ...
0
votes
1answer
48 views

Why pressure standing waves have different nodes location with respect to the corresponding displacement waves?

In acoustics the pressure wave has a $\pi/2$ phase difference with the displacement wave. But I do not understand how this leads to a different position of nodes of pressure inside a tube with ...
16
votes
7answers
4k views

How can a vacuum implode a metal tank?

An interesting video: youtube video - Railroad tank car vacuum implosion But how is it possible for a metal tank to implode? Even if one can vacuum it, it is subject to 1 external atmospheric ...
0
votes
1answer
27 views

Can a decompressed airplane cargo hold cause packaging air pads to burst / deflate?

I received a parcel from Germany to Chile recently. The contents were severely bruised due to a lack of packaging material. On second inspection I found a bunch of deflated air pads. It was a ...
0
votes
2answers
20 views

Reason for fluid pressure

What is the physical reason that high pressure regions (say, of air or water), want to expand into low pressure regions? What force is causing them to "equilibrate" the pressure? The only thing I can ...
0
votes
1answer
20 views

What does “ambient atmosphere of 20 mu” mean?

I've read through a publication from 1960 which discusses oxygen annealing. It shows a the following graph. What does the "ambient atmosphere of XY mu" mean? What is a mu atmosphere? taken from: ...
3
votes
0answers
49 views

Behaviour of Altimeter at different temperatures

I have realized that the Altimeter of my bike computer (it uses Air Pressure to determine altitude and needs to be calibrated every start) is not consistent at different temperatures. At the Start ...
0
votes
1answer
23 views

Concentration change due to different pumping efficiency

I send a mixture of two gases (5% (v/v) initial concentration) into a chamber. The chamber is pumped to a low pressure, but the efficiency of the pumping for both gases is not the same (because of ...
1
vote
2answers
59 views

Force of water hitting a wall [closed]

If you had a 8" pipe with 500psi stream of water exiting it and hitting a wall at 90 degrees 8 feet away, what would the force of the water on the wall be? Thank you all. Non-mathematician.
1
vote
1answer
67 views

Bernoulli equation and pumps [closed]

I have a doubt on the use of Bernoulli equation for pumps. Consider the situation in the picture. I marked different points: $1$ on the surface of first tank, $2$ in the exit from first tank, $3$ ...
4
votes
2answers
176 views

Static vs Dynamic pressure

According to Bernoulli's law, the narrower the tube where the fluid is flowing the lower its static pressure and the higher its dynamic pressure. Does this make any difference? If the dynamic pressure ...
0
votes
1answer
79 views

A fan is connected to a pipe, what happens to the airflow after the pressure drop?

Overview I am trying to find out what happens to the air flow within a pipe if a fan cannot generate the required pressure to overcome the friction within the pipe. After much research I am aware ...
0
votes
1answer
65 views

Using the ideal gas law to figure final pressure [closed]

I'm studying for the GRE and I'm happy with Charles', Boyle's and Gay-Lussac's laws. I'm doing some questions on the ideal gas law. Please hear me out. This may come across as a homework style ...
2
votes
0answers
34 views

How can matter be squeezed extremely dense [duplicate]

I'm fairly new to physics and currently reading A Brief History of Time by Stephen Hawking. Hawking is talking about black holes being the size of a few miles containing the mass of multiple times the ...
0
votes
1answer
41 views

Matching Bernoulli equation and Hagen Poiseuille law for viscous fluid motion

I thought that Bernoulli equation could be used only in the case of non viscous fluid. But doing exercises on 2500 Solved Problems In Fluid Mechanics and Hydraulics (Schaum's Solved Problems Series) ...
0
votes
2answers
59 views

Reversible processes in which mechanical or thermal equilibrium is not reached

The definition of a reversible thermodynamic process requires in any instant the mechanical equilibrium (equal pressures) and thermal equilibrium (equal temperatures) of the system in a quasi-static ...
0
votes
2answers
52 views

What is the difference between real value and abs value? [closed]

I am confused here, though I have been reading about it for years. What is the difference between a real value and an absolute value? For example, when do we take the absolute value of pressure or the ...
1
vote
3answers
76 views

Pressure just before the hole in a draining tank

I get extremely confused in fluid dynamics problem where the pressure in some points is required. Consider the ideal fluid in the tank in the following picture. I would like to understand what is the ...
4
votes
2answers
144 views

Weight Distribution of granular piles

I was recently at a farm watching piles of grain being formed in the shape of enormous cones. Each of these grain stacks weighs in excess of 50 tonnes. I am not a physicist but I am very curious as to ...
0
votes
3answers
46 views

Work done on gas problem with movable set

I found two different version of an exercise where the work is considered in a different way. Consider a gas in a tank divided in two parts by a movable set. The set in $B$ is also movable. If a ...
3
votes
3answers
78 views

Fluid mechanics paradox: The force needed to 'balance' a fluid using a piston

We know that the pressure in a fluid (like water) is dependent on the depth. Consider this example: For the first setup, solving the pressure at the bottom yields $P_1 = \rho gh = 1000kg/m^3 \bullet ...
0
votes
3answers
29 views

Application of Bernoullis identity for problem concerning hole in a container

Consider the following problem: We have a container of water with a hole on the side, and we want to determine the velocity of the stream coming out of the hole (at $S_2$): If we suppose $S_1>&...
1
vote
2answers
45 views

Is it possible to make iron shavings to be dust? [closed]

I'm considering how to separate iron shavings from iron. In the picture, there are some iron chunk and iron shavings. The problem is iron shavings are not dust. I want to make the iron shavings to be ...
0
votes
2answers
57 views

A dead body floats with its head immersing in water . Why?

I found this question in my practice book . I want to know about it .
0
votes
0answers
28 views

How does it come that a soda still sparkles out of the bottle, even after I can squeeze it allready?

Just noticed this right now. I have known for long time that of course, shaking a sparkled soda causes it to harden and build up pressure. When one now carefully opens the bottle it starts to ...
-2
votes
1answer
45 views

Space vacuum power

How strong is the vacuum in space? If possible in mph, or other easy to understand measurements...as someone else asked, "if you took a bottle of air into space and opened it, where would it go?" I'm ...
0
votes
0answers
25 views

Air pressure equalisation

I'm programming a physics simulation and have the air pressure impact the movement of rigid bodies in the system. I know how to (approximately, both for simplicity and performance) specify bodies' ...
0
votes
0answers
32 views

How can one calculate the drop in air temperature associated with a rise in its humidity?

Background: I wish to model the effect of an evaporative cooling system in a humid, tropical environment to be used as a feasibility study. Anecdotally, such a system would be ineffective, but I would ...