Re: Questions for those who really know their physics . . .

:: Wildepad
:: the shock of something hitting a step slows the escalator's motion,
:: then the escalator speeds up under the new load to return to its
:: average speed.

Though note, the impact of a slinky end hitting is very small.
The "step" occurs by coils redistributing over a relatively long
period of time; the impact is only the beachhead coils.

:: They can be idealized as [uniform],

Stationary stairs are also idealized as stationary, but in reality, the
support structure would give a little bit when hit, and shift as the weight
shifts down steps, and so on and so on. Shrug. Big woop.

Sure, the problems would be more severe for a moving stairway. But do you
have ANY reason to suppose they aren't manageably small? I see no reason why
problems need to be very large. Your stairway is going to outmass the
slinky by quite a large margin.

And further, your elsethread queries

_if_ a Slinky will work on an escalator at all
and
there might be a problem in that it's impetus is exactly in line
with its externally-generated movement, but that movement is not in
line with its center of gravity

made it seem clear you were asking about the linear ideal,
since otherwise talking about "movement" being "in line" makes no sense,
and "at all" seems especially clear.

If you were concerned about the stability of the escalator, then you'd
be better off asking how massive and rigid it'd need to be to stand up to
the impact of a slinky hitting it, and not about the differences between
a stationary stair and an escalator. How large a flywheel, and how rigid
the drive elements need to be. Which I suspect is, the rigidity of a
wooden frame with a relatively small balast flywheel and drive elements
no more exotic than a taut automotive fan belt would more than suffice.
Slinkys just aren't very massive, and don't make bone-jarring steps.

: Erik Max Francis <max@xxxxxxxxxxx>
: You asked a question and it was answered; is there any particular
: reason you seem to be trying to wiggle out of the (accurate) answers
: you've been given? If you wanted to ask people who knew physics
: something, why are you doubting their answers?

Indeed. Goalpost shifting, seems like.


Wayne Throop throopw@xxxxxxxxx http://sheol.org/throopw
.

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