From: tjroberts137@sbcglobal.net   
      
   On 7/22/22 12:39 PM, Julio Di Egidio wrote:   
   > centrifugal/centripetal [forces] exist in distinct frames of reference,   
      
   It is quite clear that nature uses no frames of reference or   
   coordinates, so every natural phenomenon MUST be independent of frame or   
   coordinates -- they are purely human constructs we use to DESCRIBE what   
   happens. So "centrifugal force" cannot possibly be real (a natural   
   phenomenon).   
      
   > If you hop on a merry go round and don't hold yourself...   
   > if we   
   > actually *measure* the acceleration locally, we do find that   
   > there is in a force, a very concrete one: so, to say that   
   > centrifugal forces plain "do not exist" is simply wrong and   
   > eventually misleading.   
      
   You didn't completely describe what you are discussing (your "locally"   
   is undefined). This is only "misleading" to people who ignore the   
   context and use incomplete descriptions: Yes, if you measure the   
   acceleration or force in the rotating coordinates you find a non-zero   
   "centrifugal force". If you measure it in the inertial frame in which   
   the center is at rest, you find zero force. Now see my previous paragraph.   
      
   IOW: saying "centrifugal forces do not exist" is just using the usual   
   meaning that existence applies to the world, and figments of human   
   imaginations simply do not exist.   
      
   (I agree with the moderator that that all has been said which can be   
   meaningfully said in this thread.)   
      
   Tom Roberts   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)