/sci/ - Science & Math

[Anonymous No.4383901]

I come to you, /sci/, in my hour of need!
I have two questions:
With relation to my picture, how can <span class="math">P_1 = P_2[/spoiler], if the height of the column above the two points are different? (since the formula for pressure is <span class="math">P=\frac{ah\rhog}{a}[/spoiler])
Also, how can P_2\neqP_3? (I have a feeling that the answer for the first question will explain the second)
Any errors in this post (in my quick drawing in paint, this post, or my TeX coding) shall be passed off as tiredness and not stupidity. You may pass off me not knowing the answer to this question as stupidity, however.

[Anonymous No.4383914]

>>4383901

"since the formula for pressure is <span class="math">P=\frac {ah\rho g}{a}[/spoiler] )*.
"how can <span class="math"> P_2 \neq P_3[/spoiler]*

[Anonymous No.4383920]

bump

[Anonymous No.4383930]

bampagain!

[Anonymous No.4383936]

Another way to phrase the question:

How is the pressure the same on us as we are outside with all that air above us, than inside, with almost no air above us?

[Anonymous No.4383954]

bumpppppppp

[Anonymous No.4383961]

Remember that the pressure is not just vertical. If that box were vacuum sealed and you opened it, then there would be some swirling of water because the pressures would be different. The pressures have to reach an equilibrium however, so they end up having the same pressure.

[Anonymous No.4383968]

Pascal's principle

[Anonymous No.4383974]

Imagine the pressure was higher under the column of water. The high pressure water would be pushing against the low pressure water to its right and would move that direction since it would have more pressure then the water next to it. It would eventual HAVE to equal out. There ya go champ!

[Anonymous No.4383980]

>>4383961
This I know, but with the extra tower of water, wouldn't the water under the tower have more pressure on it than a point not under a tower?

[Anonymous No.4383990]

>>4383980

It would at first, but in order for the liquid to be at rest, it would have to spread the pressure out equally among the layer it was in.

[Anonymous No.4383993]

>>4383974
READ THIS AND RE-READ THIS UNTIL YOU UNDERSTAND!

[Anonymous No.4384000]

>>4383990

But how would that happen? Wouldn't the density at point 2 have to go up, then? That can't happen, because liquid is incompressable.

[Anonymous No.4384002]

Any two points at the same elevation in a continuous mass of the same static fluid will be at the same pressure.

[Anonymuos No.4384003]

Isn't this an application of Bernoulli's equations?

[Anonymous No.4384012]

>>4383974
>>4383993

This is obvious. Difference in pressure = something has to move (in a fluid, at least). But that requires that the liquid to be compressible.

[Anonymous No.4384019]

>>4384012
Are there non-compressible fluids?

[Anonymous No.4384023]

>>4384019

A liquid is non-compressible, no?

[Anonymuos No.4384038]

>>4384023
No. Liquids are minimally compressible. Most liquids will compress to some small degree then solidify under high pressure.

[Anonymous No.4384054]

>>4384012
sure the particles constantly move in a liquid system and not just laterally but the weight of the water above will always apply pressure to the liquid below.
Any movement in the fluid will cause other movements. It is important to think about IF something happened in this closed system why would be the repercussions

[Anonymous No.4384068]

>>4384038

Derppppp.
Okay, that was definitely tiredness, because I already knew that.

I hate fluid dynamics. Pretty much every other concept in physics comes to me intuitively and the equations stick into my brain, but something about FD is all like "nopeeee"

[Anonymous No.4384081]

Think of a flask in a lab. It isn't perfectly vertical but the fluid is under the same pressure in every layer regardless.