In this related question: Slinky base does not immediately fall due to gravity

It is observed that the base does not fall immediately.

Obviously the center of mass is in free fall, and the tension of the slinky initially pulls the base up. My question is:

Does these forces cancels exactly so the base is really stationary (independent of slinky properties like mass, spring constant, ...)? Can this behavior be seen in all springs? How long does it take for the slinky to collapse?

slinky fall

(image copied from the other related question)

  • $\begingroup$ See this youtube.com/watch?feature=player_embedded&v=eCMmmEEyOO0 Got from that answer. $\endgroup$ – ABC May 6 '13 at 5:39
  • $\begingroup$ No. The answer just states the obviously: 1. Center of mass is in free fall. 2. There is tension pulling up. I am asking if the balance is perfect. $\endgroup$ – hpekristiansen May 6 '13 at 5:39
  • $\begingroup$ @007: Thanks for the reference. Interesting to see some calculation, that I could not have done quickly myself. They are calculating an estimate for the characteristic time, not the forces involved. $\endgroup$ – hpekristiansen May 6 '13 at 5:50
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    $\begingroup$ Here's a numerical analysis. $\endgroup$ – David Z May 6 '13 at 6:04