From: poutnik@privacy.net   
      
   Dne 13/11/2017 v 23:29 Libor 'Poutnik' Stříž napsal(a):   
   > Dne 13/11/2017 v 06:58 Luigi Fortunati napsal(a):   
   >> Centrifugal force is an "apparent" force.   
   >>   
   >> Ok, but I have a doubt and I hope you can clarify it.   
   >>   
   >> The sling rotates and the hand exerts a real centripetal force on the   
   >> rope.   
   >>   
   >> For the third principle, even the rope exerts an equal and opposite   
   >> force (hence centrifuge) on the hand.   
   >>   
   >> How is possible that the two opposing forces, one is real and the other   
   >> apparent?   
   >>   
   > This centrifugal force is a normal reactive force.   
   >   
   > What is meant as centrifugal force being apparent force   
   > is in the context of non inertial, rotating coordinate systems (CSs).   
   >   
   P.S.: If we consider the coordinate system of the centrifuge in rest,   
   analogical to the Earth "natural" coordinate system,   
   then any object in the rest is noticing an apparent centrifugal force   
   depending on its distance to the centrifuge axis.   
      
   F = m . omega^2 * r   
      
      
   --   
   Poutnik ( The Pilgrim, Der Wanderer )   
      
   A wise man guards words he says,   
   as they say about him more,   
   than he says about the subject.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)