Is the force given by pressure infinite?

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Discussion Overview

The discussion revolves around the concept of using pressurized gas to create perpetual motion through a mechanical system. Participants explore the theoretical implications of pressure exerted by gas on a rotating shape and whether such a system could yield continuous energy output.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that pressurized gas, such as hydrogen, exerts force on the walls of a container and could theoretically be used to create motion if designed correctly.
  • Others argue that it is impossible to extract cyclic energy from a static force field, asserting that any attempt to create perpetual motion would ultimately fail.
  • One participant notes that if gas molecules strike a paddle and cause motion, they would lose momentum, resulting in a decrease in the gas's kinetic energy and temperature, which would eventually reduce the pressure and ability to sustain motion.
  • A later reply emphasizes that discussions on perpetual motion and over-unity mechanisms are not permitted in the forum, citing community rules against pseudoscience.

Areas of Agreement / Disagreement

Participants generally agree that the concept of perpetual motion using pressurized gas is not feasible, with multiple viewpoints on the mechanics involved and the implications of energy loss in such systems. The discussion remains unresolved regarding the theoretical exploration of these ideas.

Contextual Notes

The discussion is limited by assumptions about the behavior of gas under pressure and the definitions of energy extraction in mechanical systems. There are unresolved questions about the specifics of momentum transfer and thermodynamic implications.

ageattack
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If you have a container that contains pressurized gas such as hydrogen, the hydrogen would be pressing against the walls of the container, correct? Now if you had some sort of shape on an axle that somehow allowed the pressure to spin it around, would it spin it perpetually? I know such a shape cannot be created, as the force would be distributed along all the surface area on that shape, and thus it would remain motionless. But theoretically, would this work?
 
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ageattack said:
If you have a container that contains pressurized gas such as hydrogen, the hydrogen would be pressing against the walls of the container, correct? Now if you had some sort of shape on an axle that somehow allowed the pressure to spin it around, would it spin it perpetually? I know such a shape cannot be created, as the force would be distributed along all the surface area on that shape, and thus it would remain motionless. But theoretically, would this work?

No. You cannot extract cyclic (continuing) energy from a static force field.
 
ageattack said:
If you have a container that contains pressurized gas such as hydrogen, the hydrogen would be pressing against the walls of the container, correct? Now if you had some sort of shape on an axle that somehow allowed the pressure to spin it around, would it spin it perpetually? I know such a shape cannot be created, as the force would be distributed along all the surface area on that shape, and thus it would remain motionless. But theoretically, would this work?

Berkeman is correct, the answer is no. If the gas molecules strike a paddle, for instance, causing the axle to turn, they do work and rebound from the paddle with less momentum than when they arrived. This momentum loss would be reflected in less molecular kinetic energy of translation and hence lower gas temperature. Over time, the gas would cool to the point where the resulting pressure would be insufficient to turn the axle (P=nkT).
 
Thanks klimatos.

@ ageattack -- this thread will now be locked. We don't discuss over-unity or perpetual-motion machine (PMM) mechanisms here on the PF. From the PF Rules link (at the top of the page under Site Info):

PF Rules said:
Pseudoscience, such as (but not limited to):

Perpetual motion and "free energy" discussions
http://wiki.4hv.org/index.php/Free_Energy_Debunking
http://en.wikipedia.org/wiki/Perpetual_motion
http://www.skepdic.com/freeenergy.html
http://www.skepdic.com/perpetual.html
 

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