Re: [Phys-L] ?conservation of _internal_ energy

[Diego Saravia <dsa@unsa.edu.ar>]

And if the system have a gas inside, eventually the oscillations will heat
up the gas, it will raise its T, the system will be expanded, more
pressure, more volume, work

you can apply the first law to the gas before the release of sprint and
after the oscillations stop.

2016-01-14 18:32 GMT-03:00 Diego Saravia <dsa@unsa.edu.ar>:

> probably a better abstraction of that system is a massless spring with 2
> mass in its ends
>
> one against a wall, the other free
>
> the spring was compressed ant then is released
>
> its a mechanical problem
>
> question? do the mass aginst the wall moves
>
> the system will oscilate
>
>
>
>
> 2016-01-14 18:24 GMT-03:00 Diego Saravia <dsa@unsa.edu.ar>:
>
> > 2016-01-14 16:14 GMT-03:00 John Denker <jsd@av8n.com>:
> >
> > > In the context of:
> > >
> > > https://www.av8n.com/physics/thermo/state-func.html#sec-internal-energy
> > >
> > > On 01/14/2016 08:23 AM, Herbert Schulz wrote:
> > > > Yes, imagine a gas instead of the spring. As the gas expands it
> > > > pushes the piston and does work.
> > >
> > > I say it does /not/ do work.  No work is done by (or on) the blue
> > > system. There is no F·dx: At the place where there is a nonzero
> > > force, there is no displacement. At places where there is a
> > > nonzero displacement, there is no force.
> >
> > the system is not in equilibrium, so you can not speak of internal energy
> >
> > the mass center was not moving an then it was moving, so the center of
> > mass had a force acting on it
> >
> > the system have kinetic energy coming from the work of that force
> >
> > so you have some "not internal energy" transformed in kinetic energy.
> >
> > the "not internal energy" is reflected in the expansion of the spring
> >
> > the system is acelerated, so is its mass center is not  a good reference
> > system
> >
> > the system is expanding, so is not a rigid body.
>
>
> --
> Diego Saravia
> Diego.Saravia@gmail.com
> NO FUNCIONA->dsa@unsa.edu.ar
>
> ====================================================================
> "Disclaimer:" Haré lo que desee con los correos que reciba, quien no este
> de acuerdo, que se abstenga de enviarme correo a mí o a las listas donde
> este suscripto.
> En particular NO VALE ningun "disclaimer" que indique que el correo
> enviado es privado o sujeto a normas de empresas, gobiernos, u
> organizaciones de cualquier tipo.
> Con relación a los estados y sus leyes, analizare cualquier norma
> aplicable en el territorio donde eventualmente actúe en el momento, escucho
> a cualquiera que tenga algo que decir.
> Con respecto en particular a los derechos de autor, salvo acuerdo previo,
> gozaré plenamente de las 4 libertades con todo lo que reciba,
> considerandolo, en cuanto a lo patrimonial,
> como propio.
> ====================================================================



-- 
Diego Saravia
Diego.Saravia@gmail.com
NO FUNCIONA->dsa@unsa.edu.ar

====================================================================
"Disclaimer:" Haré lo que desee con los correos que reciba, quien no este
de acuerdo, que se abstenga de enviarme correo a mí o a las listas donde
este suscripto.
En particular NO VALE ningun "disclaimer" que indique que el correo enviado
es privado o sujeto a normas de empresas, gobiernos, u organizaciones de
cualquier tipo.
Con relación a los estados y sus leyes, analizare cualquier norma aplicable
en el territorio donde eventualmente actúe en el momento, escucho a
cualquiera que tenga algo que decir.
Con respecto en particular a los derechos de autor, salvo acuerdo previo,
gozaré plenamente de las 4 libertades con todo lo que reciba,
considerandolo, en cuanto a lo patrimonial,
como propio.
====================================================================