Re: [Phys-l] energy is well defined

[ludwik kowalski <kowalskil@mail.montclair.edu>]

On Feb 19, 2008, at 2:49 PM, Bill Nettles wrote:
> Ludwik said: "One can say that energy is a concept similar to  
> work."  This bothers me a little bit. Energy is a fundamental, work  
> is a process. They are similar like dirt (energy) and a shovel  
> (work). Rather than the defining energy in terms of "work," I think  
> a better, more developed concept is that work is a process (the  
> process?) that moves (transfers) energy from place to place and  
> object to object. Define work in terms of what it does to localized  
> energy "content" (the work-energy theorem). Then say that work is  
> done on an object  by a force when the object has a component of  
> motion (displacement) parallel to the force.

Symbols in our formulas stand for physical quantities. Yes, the word  
"work" also can be used to describe a process, for example, a process  
that makes us tired, a process resulting in bringing a boat from one  
location to another, a process resulting in heating a room with  
electric current, etc. etc.  Some physical quantities (mass, charge,  
time and distance) are fundamental, while others are mathematically  
defined (directly or indirectly) in terms of fundamental quantities,  
such as  v,  m*v,  m*g*h,  0.5*m*v^2 ,  0.5*k*x^2, etc. etc. Physical  
quantities refer to objects  (such as shovels) or to various aspects  
of physical processes (such as decrease in momentum and kinetic energy).

Ludwik Kowalski, a retired physisist
5 Horizon Road, apt.2702, Fort Lee, NJ, 07024, USA
Also an amateur journalist at http://csam.montclair.edu/~kowalski/cf/