🚀 go-pugleaf

On Sat, 6 May 1995, Mervin Koehlinger wrote:

> On Fri, 5 May 1995, David J. Abineri wrote:
>
> > Look at a standing wave on a slinky. The nodal points are stationary. How
 does
> > the disturbance get from one side of a nodal point to the other if that
 point
> > isn't able to move?  It would seem that any disturbance would be stopped
 when
> > it reaches a node.
> >
> > If two congruent pulses are sent on Opposite sides of the spring
> > simultaneously they cancel exactly at one moment in time. Is there any way
 to
> > know whether, after that instant, the waves continue in the same direction
> > they were moving or in fact "bounce" off each other and return to their
> > respective starting ends.
> >
> > Any help on these would be appreciated. Thanks.  David Abineri
> >
> The motion of any particle in a translational wave is "forced" by the one
> next to it.  In a standing wave, two waves are traveling in opposite
> directions.  Thus a particle is being "forced" by two particles, one on
> either side of it.  The particle at the node experiences equal and
> opposite forces from the particles on either side of it.  Hence, it
> doesn't move.
>
> The node would be a fixed end termination.  Hence, the wave is actually
> reflected at the node.  It does not travel through.

For the higher harmonics there are nodes between the ends of the spring,
so this answer doesn't David's concern.

        -- Donald