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http://answers.yahoo.com/question/index;_ylt=Ap3mDd93By3wzuxSsf1OsHXsy6IX?qid=20070824100758AATnYe3

2007-08-24 10:23:45 · 2 answers · asked by balaji.k 2 in Science & Mathematics Physics

2 answers

I believe that all the variations on this problem (9 so far and counting) that you have posted fall into either of two basic scenarios:
1. The descending part of the chain accelerates the (finite) not-yet-falling part (e.g., the stretched-out chain that firctionlessly slides over the edge). In this case I claim that the not-falling part gets accelerated by the falling part so velocities become greater than free-fall impact velocity as the process continues, and that energy is conserved.
2. The descending part is essentially unconnected to the (potentially infinite) not-falling part, and a demon is sitting up there adding links to the top of the falling part as needed. In this situation I claim that the falling part is in a steady-state situation, falling at a speed greater than 0 and less than free-fall impact speed, so kinetic energy is indeed less than potential energy.. The missing energy goes into the inelastic collision involved in attaching a link at 0 velocity to the moving chain. This link is jerked up to speed with no rebound. Momentum, but not energy, is conserved, and all the energy is accounted for.

2007-08-26 02:09:29 · answer #1 · answered by kirchwey 7 · 0 0

seems fine to me

2007-08-24 11:19:21 · answer #2 · answered by Anonymous · 0 0

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