From: fortunati.luigi@gmail.com   
      
   Phillip Helbigundress to reply a écrit   
   >> It follows that the presence of an EXTERNAL force during the free fall   
   >> in a gravitational field, contrasts with the inertiality described in   
   >> the first principle.   
   >>   
   >> So I explicitly ask: is the free fall in a gravitational field inertial   
   >> or accelerated?   
   >   
   > I'm not sure what your question is, but if you are thinking of the idea   
   > that "a man falling from a roof feels no force", then this is true   
   > actually only in the limit if infinitely small size.  An object of   
   > finite size will feel tidal forces (and, of course, any   
   > non-gravitational forces present such as surface tension).   
      
   Is the object of finite size in free fall (in a gravitational field)   
   inertial (that is, is it not undergoing any force) or is it accelerated   
   (because it is subject to the EXTERNAL tidal forces)?   
      
   Second question: do the tidal EXTERNAL forces act only in a given   
   reference system or do they always act?   
      
   --   
   - Luigi Fortunati   
      
   [Moderator's note:  See the previous post by Sylvia Else, which answers   
   your question. -P.H.]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)