Re: test problem

[Brian Whatcott <inet@INTELLISYS.NET>]

At 05:41 AM 12/5/01, you wrote:


> In a message dated 12/4/2001 11:17:01 PM Eastern Standard Time,
> inet@INTELLISYS.NET writes:
>
>
> > No, the questions are unreasonable. If the extra downward displacement is
> > greater than the equilibrium displacement, then the possibility of coil
> > binding is not excluded on the upward rebound.
> >     For this same reason, the spring constant is not determined by only the
> > force required for a specified displacement.
> > To summarize: a) and b) are indeterminate, and c) is incorrectly modeled.
> >
>
> Does my specification of an origin (and by implication a reference for zero
> gravitational potential energy) remove the indeterminacy of b)?
>
> Justin


As you have seen from other replies, if you assume a loose coiled spring,
the initial force to extend it starts at zero.  Here, the spring rate may be
found.  The pathological case about which I also nitpicked, is the
close coiled ("coil-bound") spring, for which the force to
initally extend it is non zero.   These springs are not uncommon
(except among physics teachers, it seems)

Brian

Brian Whatcott
  Altus OK                      Eureka!