From: tjoberts137@sbcglobal.net   
      
   On 10/23/23 6:31 AM, Luigi Fortunati wrote:   
   > [...]   
      
        [The context of this question is clearly Newtonian mechanics.   
         But my answer holds for relativistic mechanics as well.]   
      
   To definitively answer the question "is inertia a vector", one must find   
   "inertia" in some equation(s). Unfortunately, "inertia" does not appear   
   in any equation of mechanics. So the question is meaningless, or at   
   least unanswerable.   
      
        [This includes Newton's original "vis insita".]   
      
   Note: do not be confused by "moment of inertia" -- look at its   
   definition and you'll see it is misnamed, and is really the second   
   moment of mass.   
      
   In modern physics,the closest quantity to "inertia" is mass, which is   
   clearly a scalar (i.e. not a vector).   
      
   Tom Roberts   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)