From: fortunati.luigi@gmail.com   
      
   Tug of war:   
   Force5 <> rope <> Force5   
      
   The two forces are equal and opposite, the resultant is zero, the rope   
   stays still.   
      
   If the two forces are not equal:   
   Force6 <> rope <> Force5   
   Force 6 prevails, a net force 1 (6-5) acts on the rope and the rope   
   accelerates to the left.   
      
   Another case: a body weighing 5 kg is hung on a string which is in turn   
   anchored to the ceiling. Everything is at rest.   
      
   If the string has negligible mass:   
   hookForce5 <> string <> bodyForce5   
   and the string stands still.   
      
   If the twine has mass 1, the force that the hook exerts on the upper end   
   of the twine is 6 (and not 5):   
   hookForce6 <> string <> bodyForce5   
   and the twine, subject to two NOT equal opposing forces, should   
   accelerate in the direction of the hook.   
      
   Why doesn't it speed up?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)