From: heathjohn2@gmail.com   
      
   On Saturday, December 16, 2017 at 1:19:31 AM UTC-5, Luigi Fortunati wrote:   
   > I'm in the car and, when cornering, the lighter on the dashboard, from   
   > my point of view, accelerates in a centrifugal direction.   
   >   
   > Since it is I who accelerate (together with the machine I am bound to)   
   > and not the lighter, can we say that my acceleration is "real" and that   
   > of the lighter is "apparent"?   
   >   
   > --   
   >   
   >   
   > Luigi Fortunati   
   >   
   > [[Mod. note -- Yes, we can say that.  Newtonian mechanics has the   
   > concept of an inertial reference frame (IRF); the Earth's surface is   
   > a fairly good approximation to an IRF.  You (in the car when cornering)   
   > are accelerating with respect to the Earth's surface (an approximate   
   > IRF).   
   > -- jt]]   
      
   Before getting into the car you picked up a helium balloon from a near   
   by circus. Now when you turn left the lighter goes right but the helium   
   balloon left, Hmmm ? Easy fix. We will make the inside of the car a   
   vacuum. You will have to hold your breath for a while. Now when you turn   
   left both the lighter and the helium balloon go right. From this I would   
   say apparent acceleration not real providing there is no such thing as a   
   balloon that is lighter than a vacuum as this returns us to the helium   
   balloon moving the wrong way. In this case it would be a balloom filled   
   with an empty void in vacuum. Which way would that balloon move when   
   turning left? You can breath now. The test is done. The question here is   
   how much does a cubic meter of a vacuum weigh? What is it's mass. It has   
   properties , 9 p farad by 1.2 u Henry, per meter so one would think it   
   has some mass?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)