OT: Slinky Question

Jim Thompson · Mar 6, 2004

If you place a Slinky on an escalator, will it go forever ?

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Michael · Mar 6, 2004

Jim said:
If you place a Slinky on an escalator, will it go forever ?

...Jim Thompson

That's a nifty concept!

Philip A. Marshall · Mar 6, 2004

If you place a Slinky on an escalator, will it go forever ?

not if the escalator is going down

or if it's going up too quickly

Bill Garber · Mar 6, 2004

: On Sat, 06 Mar 2004 11:15:35 -0700, Jim Thompson
:
: >If you place a Slinky on an escalator, will it go forever ?

:
: not if the escalator is going down

:
: or if it's going up too quickly

Or turned off, or moving too slowly.

Lots of variable left out Jim. I sort of
remember you complaining about people doing
that with your classroom tests here. 8o)

Tim Auton · Mar 6, 2004

Philip A. Marshall said:
not if the escalator is going down

or if it's going up too quickly

Indeed, you'd need to frequency-match the slinky and escalator.

Tim

Jim Thompson · Mar 6, 2004

: On Sat, 06 Mar 2004 11:15:35 -0700, Jim Thompson
:
: >If you place a Slinky on an escalator, will it go forever ?
:
: not if the escalator is going down
:
: or if it's going up too quickly

Or turned off, or moving too slowly.

Lots of variable left out Jim. I sort of
remember you complaining about people doing
that with your classroom tests here. 8o)

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| E-mail Address at Website Fax

John Fields · Mar 6, 2004

not if the escalator is going down

or if it's going up too quickly

Jim Thompson · Mar 6, 2004

I think that's the trick, John... synchronizing. Although I puzzle
over the situation where the up-rate of the escalator exactly matches
the falling period... seems to be some energy violation there that I
can't put my finger on.

(This question didn't originate with me. A woman called in to a local
talk radio show yesterday with the question, and I've been mulling
over it ever since

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Jim Thompson · Mar 6, 2004

More of a "thought-provoking metaphysical conundrum" IMV.

What's the matter there Paul? Got your panty-hose in a twist ?

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John Woodgate · Mar 6, 2004

I read in sci.electronics.design that Jim Thompson

If you place a Slinky on an escalator, will it go forever ?

Yes. Someone has done this at a London Underground station. With lots of
Slinkys. I forget what they charged him with. Excessive smart-artistry,
perhaps.

Paul Burridge · Mar 6, 2004

It's a question "for discussion" ;-)

More of a "thought-provoking metaphysical conundrum" IMV.

Don K · Mar 6, 2004

Jim Thompson said:
If you place a Slinky on an escalator, will it go forever ?

The slinky or the escalator?

Don

John Larkin · Mar 6, 2004

If you place a Slinky on an escalator, will it go forever ?

...Jim Thompson

Heat got to you already, huh?

Sit in the shade. Get an ice-cold beer and hold the bottle against
your forehead. Try to think about glaciers.

John

Bill Garber · Mar 6, 2004

: On Sat, 06 Mar 2004 19:06:57 +0000, Paul Burridge
:
: >On Sat, 06 Mar 2004 11:35:57 -0700, Jim Thompson
: >
: >>On Sat, 6 Mar 2004 13:23:31 -0500, "Bill Garber"
: [snip]
: >>>Lots of variable left out Jim. I sort of
: >>>remember you complaining about people doing
: >>>that with your classroom tests here. 8o)
: >>>
: >>
: >>It's a question "for discussion" ;-)
: >
: >More of a "thought-provoking metaphysical conundrum" IMV.

:
: What's the matter there Paul? Got your panty-hose in a twist
?

Aw, leave Paul alone. He's not a bad guy. 8o)

BTW, the Slinky on the escalator bears a striking
resemblance to the perpetual machine.

Bill @ GarberStreet Enterprizez };-)
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Email - [email protected]
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Bill Garber · Mar 6, 2004

: On Sat, 06 Mar 2004 12:52:27 -0600, John Fields
:
: >On Sat, 06 Mar 2004 18:22:59 GMT, Philip A. Marshall
: >
: >>On Sat, 06 Mar 2004 11:15:35 -0700, Jim Thompson
: >>
: >>>If you place a Slinky on an escalator, will it go forever
?

: >>
: >>not if the escalator is going down

: >>
: >>or if it's going up too quickly
: >---
: >Or if it's going up too slowly, so we'd need to servo the
escalator to
: >the slinky's period.
:
: I think that's the trick, John... synchronizing. Although I
puzzle
: over the situation where the up-rate of the escalator exactly
matches
: the falling period... seems to be some energy violation there
that I
: can't put my finger on.

Let's not forget that each Slinky will be slightly
longer or shorter than another, slightly lighter or
heavier as well.

: (This question didn't originate with me. A woman called in to
a local
: talk radio show yesterday with the question, and I've been
mulling
: over it ever since

I've thought about this quite a number times thoughout
my lifetime also, but I quickly realize that there are
more important issues at hand. 8o)

Bill @ GarberStreet Enterprizez };-)
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Email - [email protected]
Remove - SPAM and X to contact me

John Woodgate · Mar 6, 2004

I read in sci.electronics.design that Jim Thompson

I think that's the trick, John... synchronizing. Although I puzzle over
the situation where the up-rate of the escalator exactly matches the
falling period... seems to be some energy violation there that I can't
put my finger on.

The untoppled Slinky has potential energy which, as it topples, is
converted to kinetic. This applies an impulsive force on to the step
below, so that the escalator is slowed momentarily by a minute amount.
Part of the KE of the whole system is now stored as energy of elastic
deformation in the toppled Slinky, and this energy is, through the
design of the Slinky, recovered very efficiently to restore the
untoppled state.

(This question didn't originate with me. A woman called in to a local
talk radio show yesterday with the question, and I've been mulling over
it ever since

While the questioner's creativity is to be admired, that does remind me
that a fool can ask a question in a minute that a wise man cannot answer
in an hour. A wise woman, of course, would change the subject. (;-)

DarkMatter · Mar 6, 2004

: On Sat, 06 Mar 2004 11:15:35 -0700, Jim Thompson
:
: >If you place a Slinky on an escalator, will it go forever ?
:
: not if the escalator is going down
:
: or if it's going up too quickly

Or turned off, or moving too slowly.

Lots of variable left out Jim. I sort of
remember you complaining about people doing
that with your classroom tests here. 8o)

Also it is a system that consumes about twenty thousand times more
energy than it creates. The slinky doesn't need to "go forever", the
escalator does. Send the electric bill to the OP.

DarkMatter · Mar 6, 2004

Start at the top with the escalator off. When the slinky reaches
the bottom (near it), turn the escalator on, bring the slinky back to
the top, and then turn it off again. No servo, just an on off button
"server". Hehehe...

John Fields · Mar 6, 2004

Start at the top with the escalator off. When the slinky reaches
the bottom (near it), turn the escalator on, bring the slinky back to
the top, and then turn it off again. No servo, just an on off button
"server". Hehehe...

That's still a servo, hehehe...

John Fields · Mar 6, 2004

Also it is a system that consumes about twenty thousand times more
energy than it creates. The slinky doesn't need to "go forever", the
escalator does. Send the electric bill to the OP.

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OT: Slinky Question

OT: Slinky Question

Jim Thompson

Michael

Philip A. Marshall

Bill Garber

Tim Auton

Jim Thompson

John Fields

Jim Thompson

Jim Thompson

John Woodgate

Paul Burridge

Don K

John Larkin

Bill Garber

Bill Garber

John Woodgate

DarkMatter

DarkMatter

John Fields

John Fields

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