Quantized Elevator Gedankenexperiment?

Most of us are familiar with the toy called "Slinky"; a cylindrical coil of flattened steel wire, and how it can "walk" down stairs.

Now consider one placed on an escalator; an ideal escalator carefully built so that its steps are exactly the right depth and width to match the step length etc. of the Slinky.

Note that a Slinky "walks" down stairs with a constant velocity. Hence from the Slinky's point of view, it cannot tell whether it's walking down stairs in a gravitational field, or the steps are moving up under it.

  (This is inspired from a post in another group in which the OP wonders:

"1. Will this work?"

  which I believe we all agree the answer to is "yes", and:

"2) If so, how much is the 'tumbling' speed be affected by temperature
(i.e. if I build a desktop escalator with a miniature slinky on it,
could it be preset or would there have to be sensors to detect if the
Slinky is staying near the middle and adjust the speed accordingly)?"

  which is more a matter of engineering than physics.)

Now this may seem a trivial "improvement" on the original version, but it might stimulate some fruitful discussion. Or, it may just set the anti-Einstein trolls off. Or both.



  Mark L. Fergerson

.

Relevant Pages

  • Re: Questions for those who really know their physics . . .
    ... Now, granted that I'm not quite over the tryptophan near-poisoning from last night, and I metabolize eggnog rather faster than most people, but for the life of me I can't see why this doesn't equate to a special case of the elevator gedankenexperiment in that a Slinky on an escalator can't tell whether it's "falling" down the stairs or the stairs are moving up under it. ... Thus the frame comoving with the steps -- that is, where the steps appear to be at rest -- is an inertial frame. ...
    (rec.arts.sf.science)
  • Re: Quantized Elevator Gedankenexperiment?
    ... Now consider one placed on an escalator; an ideal escalator carefully built so that its steps are exactly the right depth and width to match the step length etc. of the Slinky. ... Hence from the Slinky's point of view, it cannot tell whether it's walking down stairs in a gravitational field, or the steps are moving up under it. ... I was hoping somebody'd notice that whereas in the original, we're forbidden from taking measurements at two points within the elevator which would show a gradient in the perceived acceleration but that in the Slinky case we're forced to "spread a point out" to cover two steps so that we have to consider what goes on _within_ the point, where a acceleration gradient might be observed. ...
    (sci.physics)
  • Re: Questions for those who really know their physics . . .
    ... If you can get a slinky to 'walk' down a long run of stairs, ... no doubt it will also 'walk' down an operating escalator. ... how much is the 'tumbling' speed be affected by temperature ... play back a five-minute tape twice without a variation of a half ...
    (rec.arts.sf.science)
  • Re: Questions for those who really know their physics . . .
    ... :: then the escalator speeds up under the new load to return to its ... the impact of a slinky end hitting is very small. ...
    (rec.arts.sf.science)
  • Re: Quantized Elevator Gedankenexperiment?
    ... > Now consider one placed on an escalator; ... >built so that its steps are exactly the right depth and width to match ... > Note that a Slinky "walks" down stairs with a constant velocity. ...
    (sci.physics)