Re: CONSERVATION OF ENERGY

[Jim Green <JMGreen@sisna.com>]

At 09:26 AM 7/30/97 -0400, Barlow wrote:

> Jim,
> 	The rest of the situation is illuminated!  

It is????

Consider the case 
> which has already been mentioned in this thread.  A heavy cylinder is 
> filled with a mixture of gasoline and air sealed and insulated.  In the 
> side is a spark plug to which we can apply a spark whose energy 
> contribution may be considered negligible.  The temperature goes up when 
> the plug sparks; the pressure increases; 

> but no heat is transfered, 

Tell me what this means -- heat being transferred.
                                                         
> no work is done, 

There is no external work done, but what is meant by "no work"

> and there is no change in internal energy.  

Tell. me how you are specifying "internal energy"

> In order to 
> understand how this can be we have to include all of the energy in the 
> internal energy.

The problem can also be analyzed in other ways, but in order to discuss such
a problem we need to agree on language.

In the case on the sliding block the problem can be analyzed by either
including the KE of the block in the internal energy or by excluding it.
Leigh wants to include it.  Ok I can use his language.

My point was that there is not much advantage in trying to make an all
inclusive, permanent, universal definition for "internal energy" unless the
rest of T#1 is in the definition.  And T#2 as well, for that matter.  At
least for many of us.  Otherwise, it becomes like this thread -- with people
just taking turns speaking without communicating -- talking past one another
just as at a cocktail party.

Jim Green
JMGreen@sisna.com