Re: How does fluid under pressure have potential energy?



Igor wrote:
On Oct 11, 5:09am, "Y.Porat" <y.y.po...@xxxxxxxxx> wrote:
On Oct 8, 2:33am, Igor <thoov...@xxxxxxxxxx> wrote:





On Oct 7, 11:23am, nonse...@xxxxxxxxxxxxxx wrote:

All the proofs I have seen online say to multiply Pressure by the
Volume to get the potential energy of the fluid. I do not understand
what this energy actually represents? Couldn't you apply the same
logic to a solid and say it also has potential energy equal to
Pressure times its volume?

You can think of pressure as a potential energy density. That's why
you need to multiply it by volume (or integrate it, depending on the
circumstances).

We'll keep things relatively simple and say we have a fluid at a
particular constant pressure P. But remember that pressure is force
per unit area, so the force exerted by the pressure is F = P A, where
A is the total area over w
Pressure is force/area. Since when does something have be moving to have a force acting on it?

Every time. No dp/dt no force. A floating piston of 1 in sq is
exposed to air at atmospheric pressure on both top and bottom
surfaces. Since F=dp/dt there can be no force when there is an
absence of mass undergoing acceleration. Is it correct to say that
the air is exerting no force on the piston's top surface simply
because the piston isn't moving? No, however a change in momentum per
second of the atoms and particles within the piston is occuring,
because they are accelerated by the impacts of the air molecules.
There is mass in motion in this example, though an electron microscope
might be required to witness it. By extrapolation it can be inferred
that a similar mass flux exists in the cases of electromagneic and
graitational forces. In fact the force on the piston is entirely
electromagnetic in the example above. Think about that for a moment.













There is mass in motion.
While the piston isn't moving as a wh







.

Relevant Pages

  • Re: Double counting gravitational potential energy
    ... paradox is entirely in the internal energy of the pressure term need ... the rest mass. ... potential energy removed from the system, ...
    (sci.physics.research)
  • Re: Scientific Errors
    ... erroneously taught that the pressure of an accelerating fluid decreases ... as the velocity of the fluid increases. ... decrease in force opposite the direction of motion. ... surface area of the piston. ...
    (sci.physics)
  • Re: How does fluid under pressure have potential energy?
    ... Volume to get the potential energy of the fluid. ... Pressure times its volume? ... each moving in a direction opposite to the ...
    (sci.physics)
  • Re: Boiling brake fluid Redux
    ... This provides the pressure release ... >>>As gum builds up on the piston, the retraction action is reduced, then ... >> slightly by any slight wobble or unevenness in the turning disc but as ... >Think of fluid dynamics: you've pressed the pedal, ...
    (alt.autos.toyota)
  • Re: Hydraulic force question
    ... >> pressure will go to the other side, and you have 441.775 lbs of clamping ... >> pressure, the force is still 883.55 lbs per piston, but you do not divide ... > spindle with all the force. ... calipers have a far greater piston diameter than the equivalent ...
    (rec.crafts.metalworking)