Re: [Phys-l] vector inconsistencies

["Bob Sciamanda" <trebor@winbeam.com>]

> Marginal cases can be found in thermodynamics:  A pressure
> gradient is like a force, so it should probably (?) point
> downhill ... but what about a temperature gradient, or a
> concentration gradient?????

You draw the vector to represent whatever it is that you want to express 
(assuming that this is well defined in your mind).  The drawn vector is 
simply a graphical language to express what you want to say.

The conventional definition of the spatial gradient of a scalar field V(r) 
is Grad V(r) = DELTA V(r) / Delta(r).  The vector Grad V(r) is thus defined 
to show the direction of increase of V(r).  Since a conservative force is 
calculable as a negative gradient, F(r) = -GradV(r) and shows the direction 
of decrease of V(r).

I don't see your problem.

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
http://www.winbeam.com/~trebor/
trebor@winbeam.com