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New answers tagged pressure

3

The question is asking what is the force exerted by the water on either of the two faces of the plate. The net force will be zero as force on either side sides cancel, so your intuition made sense. The force on a side comes from water pressure across the triangular surface. The pressure at any point on the triangle depends on the depth of that point. ...

0

Wait, don't bother. I found the embarrassing error. It's the H' value. It should have been: $$H' \equiv \frac{ M_0 G M }{R T } \approx 4,739,000 \text{ km}$$ I just read that output wrong. The plots now seem to fit. Sorry to answer my own question so fast. I suppose whether any of this is right remains an open question.

4

Creating a vacuum above carbonated drinks causes the CO2 to outgas faster--simply because there is no CO2 above the drink to diffuse back into the liquid. In physical terms this means there is no vapor pressure of CO2 above the liquid, so net movement of CO2 is from the drink to the space above it. If you leave a closed carbonated drink bottle long enough, ...

4

Your mistake is to assume that the water will stop "no matter how long a bottle you take". It will not - you just need a longer bottle than you expect. To be precise, you need a column of water 10 meters high to counteract atmospheric pressure.

-1

I think it is a question how hard you can suck the water in. The force $F$ you need to accelerate the water column depends on the mass of water: $$F=mg.$$ And the mass depends on the density $\rho$ and the volume $V=hA$ with the length $h$ and the surface area inside the straw $A$. So, the force you need to accelerate the water column is proportional to ...

0

Thickness for a window made of a brittle material (like most glasses) is Thickness = sqrt( pressure * radius^2 / Modulus of Rupture ) Where Modulus of Rupture is roughly the tensile strength, it's listed for most materials in data books or http://www.sgpinc.com/materials.htm Be careful that the pressure and modulus are in the same units . In real life ...

0

While studying the behavior of a gas filled balloon on cooling down, one needs to understand how the gases behave while being cooled. A helium filled balloon immersed in liquid nitrogen would just undergo shrinkage due to contraction of helium gas. On the other hand, a balloon filled with air will behave differently. Air roughly contains 77% nitrogen, 22% ...

0

There are different types of deformations that result in different stresses. There are axial, bending, shearing, twisting and buckling modes that may need to be considered. If you are dealing with beams, I suggest read up on the theory of beams, and look into a Engineer's Handbook, or even better the Roark formulas for stress and strain book. Find an ...

0

In case your question stemmed from seeing a similar phenomenon yourself, what you saw might have been an antibubble. An antibubble is a droplet of water, encased in a thin shell of air, suspended in water. These are pretty unstable in nature, so they're rarely observed unless artificially induced. An antibubble will have roughly neutral buoyancy, being ...

2

But if this is true, why is hydrostatic pressure perpendicular to the surface it acts on instead of always going down? Because of the properties of a fluid. A fluid will not tolerate directionality in force. If you have a jug of liquid and poke a hole at a surface below the water level, the fluid is ready to flow out in any direction, left, up, down, ...

-2

Atmospheric pressure is caused by air gravity and air molecules movement, air pressure in the half filled upside-down cup is lower than the air pressure outside due to less gravity, so the air pressure can still hold the water in half filled cup.

1

If you are hoping for a gas that can compress to exceed water density without itself condensing into a liquid, my guess is that the search will be difficult if not impossible. Uranium hexafluoride at 5 bar and $120^\circ C$ is a gas that is denser than liquid hydrogen for example but LH2 cannot exist in this condition. I would be interested to know which gas ...

2

Even ignoring that under high pressure the gas won't likely be a gas anymore, let's see what kind of pressure would be required. Air is a mixture of N2 and O2 with molecular weights of 28 and 32 respectively. There is more nitrogen than oxygen, so let's use 29 for the molecular weight for "air". One mole of air therefore has a mass of 29 grams. At ...

2

We need a phase diagram for the gas in the balloon. I found one for CO2 The pressure at the bottom of the ocean can be estimated as 1 atmosphere every ten meters depth. For 4000 meter that is 400 atmospheres. Temperatures at the bottom of the ocean are above icing, a few C, so from the diagram a balloon with CO2 released by a bathysphere at a suitable ...

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