Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-l] energy is well defined.



John,

I am somewhat concerned about the words "converted to" in the definition of energy. Suppose I consider a block of wood that is sliding on a wooden table top. The block slows down and I can feel that is warmer than before. The gross kinetic energy of the block (a known type) has been converted to internal energy (consider this the new unknown type). However, your definition seems to require that I be able to convert the new type to the old. Don't I run into all the old 2nd Law problems defining energy if I attempt to do this? Wouldn't "converted to or from" cause fewer problems when extending energy to new types?

Bob at PC

________________________________

From: phys-l-bounces@carnot.physics.buffalo.edu on behalf of John Denker
Sent: Mon 2/18/2008 3:40 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] energy is well defined.




I am still looking for the well defined statement of energy, suitable for my
neophytes,

The best I can do is:
http://www.av8n.com/physics/thermo-laws.htm#sec-energy-def

It's less than 175 words. It's not super-simple or super-concise,
but it has served me well all these years. It's an operational
definition, optimized more for practicality than elegance.