Re: Elastic potential energy (repeat)

["RAUBER, JOEL" <JOEL_RAUBER@SDSTATE.EDU>]

You are right, I misunderstood your terms; my relaxed position was x = +xo;
this, of course, explains the sign descrepancy and means that we were
pointing out identical features.

Joel Rauber
> I suspect there may be some misunderstanding of terms.  My "xo" is
> intended to indicate how much the spring is *stretched* at the
> arbitrarily chosen "reference position" and my "x" is a coordinate
> with origin at the reference position that is positive in the
> direction of *increasing* stretch.  With these definitions, the
> relaxed spring corresponds to x = -xo and the force equation is F
> = -k(xo+x).  The resulting equation has the desired features
> 1) that the potential energy is zero at the reference position and
> 2) that it recovers the usual formula (k/2)x^2 when the stretch
> at the reference position is 0.
>
> John Mallinckrodt      mailto:ajm@csupomona.edu
> Cal Poly Pomona          http://www.csupomona.edu/~ajm