Re: Bernoulli

[Bob Sciamanda <trebor@VELOCITY.NET>]

> A net force acting on
> a parcel of water can change its kinetic energy but it can not
> change its potential energy. Right?

Why do you say this? The raw CM WE theorem says that the CM work of the
net force on an object is numerically equal to the change in that object's
KE.  A further development of that theorem shows that if any of the forces
is conservative, then its contribution to the CM work can be taken over to
the RHS of the equation as a change in a "PE" function.

This merely gives a different taxonomy: Rather than say that the CM work
of all of the forces (including conservative) contribute to the change in
the KE, one can now say that the CM work of only the non-conservative
forces contribute to the changes in the SUM of KE plus PE.  Not a
different physics - just another way of arranging one's stamp collection.


Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "Ludwik Kowalski" <kowalskiL@MAIL.MONTCLAIR.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, November 16, 2001 10:22 AM
Subject: Re: Bernoulli