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Re: dropped slinky



At 04:37 PM 11/22/02, Timothy Folkarts, you wrote:
OK,

I admit my first reaction was wrong. The top does accelerate down quickly.
An interesting extension to Carl's spring analysis (sorry about the pun) is
that the spring is continuous. Thus, if we take the limit (looking at
either many rings, or subdividing the rings into many segments), the very
top of the very last ring will have (in principle) an infinite acceleration
as you let go!

In retrospect, I guess that isn't so hard to swallow. The last millimeter
has practically no mass, but is subjected to the full mg force. I can't
remember ever running in to an infinite acceleration before. (Of course,
various real-life limitations will prevent an actual infinite acceleration,
but it is still an interesting concept.)


Timothy Folkerts

Department of Physics
Fort Hays State University
Hays, KS 67601
785-628-4501


An infinite acceleration, extending over an infinitesimal
change of position, possibly?
How does one assign a value for the acceleration
experienced when any particle at rest, begins to move?
The change of velocity is discontinuous, is it not?

Brian Whatcott
Altus OK Eureka!

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.