RE: addendum to : reply to Rick

["Richard W. Tarara" <rtarara@saintmarys.edu>]

Just seems to me you have gotten too complicated here.  One of your
purposes for introducing 'forces' into the non-inertial frame was (I
thought) to preserve a 'Newtonian' view.  Now you're willing to abandon
the third law where convenient.  I think your methodology involves too
many 'ifs', 'ands', and 'buts'.  To adopt the 'Marlow' view for
introductory work, I need only preserve gravity as a 'traditional'
force--thus only one 'but'! ;)

Actually my preferred way to work with the non-inertial frames is NOT to
analyze from within.  That is, we acknowledge the sensations within the
accelerating frame BUT then analyze it from the point of view of the
inertial frame.  This then allows the student to 'see' that the effects
felt ARE 'backwards' from the real forces causing them.  This seems to
work reasonably well in my classes!

Rick

----------
> From: Rauber, Joel              Phys
> To: physic-l
> Subject: addendum to : reply to Rick
> Date: Wednesday, May 01, 1996 10:02 AM
>
>
> The solution (a) I gave is not all that different from the spirit of how
one 
> solves the following mechanics problem in an inertial frame!!
>
> You have a bunch of charged, massive partices, some of them hooked
together 
> with springs and some with (massless, non-stretchable) ropes attached 
> between them etc etc.  There is also a non-uniform magnetic field
present, 
> agent unspecified.  What is the motion of the system.
>
> One solves this applying Newton's 2nd law, that is solve the equations
of 
> motion!  You never need to worry about using Newton's 3rd law to
whatever it 
> was that produced the non-uniform magnetic field. You may find it
helpful to 
> apply the 3rd law between some of the particles present in the system
whose 
> motions you are trying to analyze.
>
> Joel Rauber
> rauberj@mg.sdstate.edu