Re: are normal reaction and tension conservative ?

["John S. Denker" <jsd@MONMOUTH.COM>]

At 01:47 PM 6/30/01 -0400, Chuck Britton wrote:

> Back in the late '60's, some dude named Goldstein had a text book on
> Classical Mechanics

:-)

> that left me with the IMPRESSION that any
> velocity dependent force is non-conservative.

Almost any.  A charge moving slowly through a constant magnetic field is
the obvious exception, because the force is normal to the velocity, as
Chuck noted:

> When presenting magnetic forces (QvB) to neophytes we say that no
> work is done since the force is normal to the displacement.

Right.

> (When DOES the radiative component enter into our curriculum?)

Maybe when the charge moves more quickly?

> I can also say the words 'holonomic(sp),

That constrains the system to a subspace of whatever state space it would
otherwise have had:

  http://webug.physics.uiuc.edu/courses/phys326/spring01/lectures/lagrange_
http://webug.physics.uiuc.edu/courses/phys326/spring01/lectures/lagrange_2/t
sld003.htm


>  scleronimous(sp)

That's usually "scleronomic".  Same as above, with the added feature that
the constraint equation has no explicit time-dependence.
  http://www.aa.washington.edu/courses/aa571/notes4.pdf

As a rough analogy: in chess, the bishop is subject to a scleronomic
constraint (always red or always black);  the knight's constraint is
non-scleronomic (alternating red and black) if we interpret "time" to be
the number of moves that piece has made.