From: relativity@paulba.no   
      
   Den 31.01.2026 20:43, skrev Maciej Woźniak:   
   > On 1/31/2026 8:21 PM, Paul B. Andersen wrote:   
      
   >>   
   >> How do you think Newton would have answered the following   
   >> questions?   
   >> An object with mass m is stationary when t < 0.   
   >> At the time t = 0 a force F is applied on the body.   
   >> Would he have said that the body can never accelerate because   
   >> it's speed is zero?   
      
   No answer, Maciej?   
      
   If you hold a ball in your hand, the speed of the ball   
   is zero both in its rest frame and in your rest frame.   
      
   That means that it is impossible for you to throw   
   the ball because "velocity 'in own rest frame' is   
   always 0, no acceleration. Sorry, trash."   
      
   Maciej's law:   
   "It is impossible to make a stationary object move."   
      
   >> You sit in your car with an accelerometer in your hand.   
   >> The accelerometer shows that your acceleration is a = 2 m/s².   
      
   > No I don't.   
   > Delusions, poor trash. Like always.   
   >   
   > And, no, your "accelerometer" doesn't measure   
   > any accelerations.  You're a true idiot buying   
   > this crap.   
      
   So I am an idiot because I believe that an "accelerometer"   
   is an instrument which measures acceleration!  :-D   
      
   It is remarkable that a person who is posting in a sci.physics   
   Usenet group is ignorant of the existence of accelerometers.   
      
   Inertial Navigation Systems (INS), also called   
   Inertial Reference Systems (IRS), are used in aircrafts,   
   ships, submarines, missiles, spacecrafts, robots, drones,   
   you name it.   
      
   All commercial aircrafts must have one or multiple IRS.   
   That is because the IRS is independent of information   
   from the outside (GNSS, radio beacons, radar) which   
   may not always be available under all conditions.   
      
   An IRS consist of three accelerometers and three gyros   
   (ring lasers) measuring the acceleration along, and   
   the rotation around the aircraft's three axes: Roll Axis,   
   Pitch Axis and Yaw Axis.   
      
   When the IRS is switched on, the aircraft must stay   
   stationary in 20 minutes.   
   During that time, the gyros will have found the direction   
   of Earth's spin axis and the accelerometers will have found   
   the direction of a vertical to the ground (acceleration is upwards).   
   The angle between these two axes will give the latitude   
   of the aircraft's position, and the angle between Earth's spin axis   
   and the Roll axis will give the heading of the aircraft.   
   The longitude must be entered manually.   
      
   The position is found by integration of the acceleration.   
   The direction is given by the gyros.   
      
   So you see, accelerometers measures acceleration, and   
   thousands (millions?) are in action right now.   
      
   Think of this the next time you fly.   
      
   --   
   Paul   
      
   https://paulba.no/   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)