Force per unit area.

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68 views

Warning: Gruesome. Which one cuts faster? Guillotine with a slanted blade or with a flat blade? [duplicate]

The following image shows Guillotine that is a device designed for carrying out executions by decapitation. Intuitively, slicing with pushing is less effective than slicing with pushing and ...
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0answers
182 views

Horizontal Capillary Question

I have a fluid mechanics question, that I think is caused by a lack of understanding of some key concepts. Suppose we have a horizontal capillary with a radius of 10um. The fabrication process has led ...
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0answers
43 views

Bulk transport of an aerosol by a blast wave

I'm trying to model the behaviour of aerosols in response to blast waves. (This is for visual effects.) Intuitively, if a flare left a smoke trail above a field and then a bomb detonated elsewhere ...
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0answers
292 views

ideal gas law modelization in a vacuum chamber

I am trying to model a pressure sensor in COMSOL. The basic work is that there is current flowing inside it, if the pressure of the gas around it drops down, the temperature goes down as well (ideal ...
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2answers
887 views

Water pressure on slanted wall

Water pressure is simply $pgh/2$ for a vertical wall parallel to the depth of the water at exactly the half the water's depth. Suppose the wall is tapered (angled) slightly at around 2 degrees from ...
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0answers
138 views

How to solve state parameters using these givens for an ideal gas?

In a thermodynamic turbine using air as an ideal gas, given that you have a known inlet temperature value $T_i$, a known exit pressure value $P_e$, a known inlet and exit velocity $V_i$ and $V_e$, a ...
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0answers
46 views

pressure required for displacing a single electron off a crystal

I need to know this for my project- "power generation using the pressure applied on a keypad of a mobile electronic device". How much pressure does it take to displace a single electron off its ...
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0answers
90 views

Radiation Pressure [closed]

How much radiation pressure would be required from the sun for a carbon atom on the surface of the Earth to reach an acceleration of 1G? Can you show all the math required for the answer...thanks
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59 views

Can I use computer fans and tubes to lower the air temperature below dew point?

I suppose to build a small dehumidifier, but I am narrowing the question down into its logics. I have relatively powerful computer fans, water cooling radiator and some metal tubings. With the idea ...
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0answers
92 views

Determining Water Level

Given a cylinder of a constant shape and size, how can the water level be calculated using the inside surface of the container? For instance, could the inside lining of the container be a pressure ...
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2answers
832 views

How is energy transferred from one incompressible fluid to another?

When you apply pressure to an incompressible fluid the pressure is transferred. If you stop applying the pressure there is no motion. Volume and density are integral parts of calculating how much ...
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2answers
178 views

Amount of material required for a pressure tank

I read the answer for the question Why is a hot air balloon “stiff”? and thought something sounded ridiculous. My engineering requirement is that the walls be strong enough. Here $T$ will be the ...
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0answers
88 views

What is approximately critical Q for the space shuttle? [closed]

Everything is in the title, I wonder what was approximately the critical dynamic pressure the space shuttle (RIP) could handle, as I am trying to create a simple space flight simulator. I don't need a ...
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4answers
2k views

Physics of the inverted bottle dispenser

When you invert a water-bottle in a container, the water rises and then stops at a particular level --- as soon as it touches the hole of the inverted bottle. This will happen no matter how long ...
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2answers
846 views

Would weighing scales show a negative weight if placed in a vacuum?

The weighing scales in my kitchen are currently showing 0 Kg. However, there is a column of air between the scales and the ceiling that is presumably exerting pressure on them. If I were to place ...
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6answers
7k views

Is it possible to generate electricity using a water tower?

Is it possible to build a water tower that will provide enough pressure to run an electricity generator? A water pump can be used to send water up to the tower. The water pump can be powered by solar ...
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3answers
73 views

Does acceleration affect the pressure?

I would like to measure the pressure inside the car ( by a pressure sensor or the altimeter). If we consider that the temperature inside the car is constant, do the car's velocity or acceleration ...
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4answers
76 views

Could atmospheric pressure provide a torque to turn a wheel?

Imagine a smooth wheel. Now imagine it is divided up into four "pizza slices". We came up with an idea where you would put the bottom two "slices" along with the top left "slice" in a very low ...
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3answers
269 views

Lethality of sounds and extreme “loudness”

In theory, could pure sound be lethal? How loud would it have to be? Also, which events are the loudest in the universe, and how loud are they? I'm confining attention to events which occur regularly, ...
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2answers
104 views

How many psi's are in one bar?

6894.7573 bar = 100000.0 psi according to google 6894.7573 bar = 100000.0001 psi according to wolfram alpha which is it? How many psis are in one ...
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2answers
140 views

Why is there a limited range of possible soap bubble size?

Soap bubbles are never "too small" or "too large". What defines the range of possible diameters of a soap bubble? Related questions: Why do steam bubbles increase in size as they rise, Why is the ...
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5answers
815 views

Does the pressure inside a tire equal to its average ground pressure?

On one hand, I think they should be equal since the external force and internal force are equal in equilibrium. On the other hand, I don't see anything related between them, the inside pressure is ...
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3answers
337 views

Upward bouyant forces?

When an object is submerged in a fluid (e.g., water), there is a pressure on the object due to weight of water by p=mgh, but why is there an upward buoyant force?
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1answer
113 views

In Newtonian pressure, what type of function is force?

This is pressure in Newtonian mechanics: $$P=\frac {dF}{dA}.$$ What does this mean? (Doesn't it mean that force is a function of area?) What type of function is force?
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1answer
38 views

The significance of the pressure term within the momentum-energy tensor [duplicate]

EDIT: this question is based around my notion regarding the possible role of potential energy in the momentum energy tensor T$_{\mu\nu}$, The answer below resolves the question and I have deleted ...
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2answers
115 views

requirements for hydrogen fusion

What are the requirements for hydrogen atoms to go through fusion? Is it a ratio of heat to pressure or are there specific heat and pressure values that must be met (per atom or per mole?) Are there ...
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3answers
9k views

High and low pressure area and raining

In the high-pressure area it is mostly likely that there is sun. In low pressure area it is mostly likely that rain will occur. Because of the law that ...
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1answer
471 views

thought experiment involving water pressure

If I were to move the syringe up, and cause it to be stationary, how does that effect the pressure at the bottom of the pipe? How does the movement of this water effect the system setup and ...
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3answers
267 views

What is the volume of a parcel of air of a giving weight at average sea level pressure

I know this is probably some basic math once you have the figures, but my Google-fu is failing me. Say I have 5 pounds of air. Air meaning, the typical composition of the atmosphere of Earth. And by ...
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1answer
49 views

Why does plugging a hole in an airplane's fuselage result in a huge (10x) atmospheric pressure spike?

While reading about uncontrolled decompression, I came across one famous airline incident, Aloha Airlines Flight 243, where the article I was reading discussed a 1-square-foot hole created in the ...
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1answer
46 views

Why is the melting point of an object inversly proportional to pressure?

In my science book it is written that as the pressure increases the melting point of a solid decreases but i think that it is wrong as the pessure will make the molecules stick together instead of ...
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5answers
456 views

Do particles always flow from high to low pressure?

In a recent question, it was stated that particles in high pressure air always flow to lower pressure. In a pipe with a constriction, fluid flows from from low to high pressure after the ...
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1answer
42 views

Avalance diode -looking symbols with two triangles in the case of backpressure pump? [closed]

I cannot understand the symbols where you have some q terms, some arrows and white triangles. It is related to managed pressure drilling (MPD) of the system where the system is different to ...
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1answer
43 views

Calculating velocity from a pressure distribution

Using computational fluid dynamics I have calculated the pressure distribution over a streamlined body. I have access to the static, dynamic and total pressure seperately and assume that I can use ...
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2answers
238 views

Direction of pressure in fluids

ok so my friend told me that in a container, the pressure exerted by the walls on the liquid in the container act in the upward direction.Is he correct ? so what I am imagining is a cylindrical ...
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1answer
60 views

What happens to the gas in the container in this picture when the container is tilted

So the test question asked what would happen to the gas if this container were tilted on its side. The piston shown here is 10 kg and moves frictionlessly. I said that the pressure inside the ...
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1answer
100 views

Viability of Dysons bladeless fans? [closed]

Do Dyson's bladeless fans produce enough air pressure to cool say an air conditioning unit and do they produce a vortex pressure like a bladed fan?
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1answer
936 views

Density of Air in a balloon

A balloon with volume 2800 m³ is heated up to 60 °C. If the outer temperature is 12 °C and the air has a pressure of 960 hPa, what is the density of the air inside the balloon and on the ...
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1answer
187 views

If a balloon is continuously filled with air and stays at a constant shape and size will there be any empty space in the balloon?

If a container like a balloon but with constant volume is filled, is it possible to pack air molecules so closely together that they don't have any empty space between them? If so, what would this ...
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3answers
1k views

Units of Distance, Pressure, and Temperature [closed]

I need to store data. I'd like to store them in Metric units and use a tool to convert them to and from other units that these data points will be displayed in. As the title states, my constraints ...
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4answers
154 views

Why doesn't atmospheric pressure crush thick walled structures?

There is one thing that puzzles me: common explanation of why don't structures collapse under the enormous atmospheric pressure (~101300N/m^2) is that the force pushing from inside balances out the ...
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2answers
74 views

Negative pressure

How is negative pressure created in a fluid system?Isn't it counter intuitive that we are reducing the pressure of a system containing no molecules(zero pressure) to a lower value?
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1answer
135 views

If we dropped an object into the Pacific Ocean, would it completely sink to the bottom of the ocean floor or not?

Obviously if the density of the object is smaller than the density of water it would not sink at all. But I was thinking that, even if the density of the object is greater than the density of water, ...
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4answers
127 views

Can this container withstand a vacuum? [closed]

I am putting together a piece of equipment that will involve a vacuum pump pulling up to 10 Torr / 13 Mbar.  I need to use a container for liquid within the equipment and have found a stainless steel ...
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2answers
66 views

Would an airtight box filled with air act the same way to 1 bar of water pressure as the same box vacuum-sealed at atmospheric pressure?

Pressure On average, a column of air one square centimeter in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kg and weight of about 10.1 N (2.28 lbf) ...
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1answer
80 views

How to convert cc to bar?

In astronomy/astrophysics, medium density is often given in cc, particles per cubic centimeter. Also, the temperature of the medium is usually given, in Kelvins. For some materials the melting point ...
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2answers
410 views

Calculating pressure under water

Say I were calculating the pressure under 1 foot of water, in psi. I'm thinking the pressure is force per unit area, and should be equal to the force exerted by the column of water standing over ...
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1answer
10k views

Calculation of pressure from flow rate of water

Anybody kindly help me to find how to calculate pressure in bar from flow rate. I have a pipe and from that I am transferring water at a constant flow rate of 5ml/min. At this flow rate, with a 0.5 cm ...
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2answers
280 views

Pressure $p$ in the Bernoulli equation

I know the Bernoulli equation that states that the energy along a streamline is constant: $$ \frac{v^{2}}{2}+gh+\frac{p}{\rho}=C $$ However I can't seem to figure out what exactly $p$ is in this ...
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4answers
97 views

Find pressure of liquids without making contact with it

Is there any way to find the pressure of a liquid inside a closed container without making contact with it? You can make any assumptions, like transparent container or anything, only rule, the ...