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
"The only thing necessary for the triumph of evil is for good men to do
nothing." - Edmund Burke
This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.