Re: There's work, and then there's work

[Jim Green <JMGreen@SISNA.COM>]

At 04:00 23 01 2003 , the following was  received:
> As a spin-off from another thread, let me explain my appreciation of the
> differences in the use of the term "work" between
>
> (1)the CM Work/KE theorem of mechanics, and
> (2)the First Law of Thermodynamics.

It sometimes amazes me to see the awkward gymnastics done to separate the
work done in Chapter 7 (W=Fdx) from the work done in  Chapter 20 (W&Q) It
is the _same_ process!

Why would a competent instructor think of a billiard ball hitting another
such ball a different process from a hot molecule's hitting another
molecule.  It is the _same_ process!

Now if in addition one wants to contort the language of physics and talk
about "energy transfer" and further muddle the student's mind, then note
that the level of system energy is changed in exactly the same way in each
case.   The work/energy theorem operates the same way in each case.




Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen