From: helbig@asclothestro.multivax.de   
      
   In article , Luigi Fortunati   
    writes:   
      
   > I entered the elevator, I placed an electronic scale on the floor and,   
   > after starting, when the elevator bought steady speed uphill, I weighed   
   > myself and the display showed 83.5 kg.   
   >   
   > I repeated the operation during the descent at constant speed and the   
   > display showed a weight of 83.2 kg.   
   >   
   > Is it a strange result or does it correspond to the theory?   
      
   Everything you observe corresponds to theory, because (in this case),   
   the theory is correct.   
      
   It would be a strange result in the case of weighing while the elevator   
   is moving at a steady or constant speed.  I'm pretty sure that your   
   elevator does not move at a constant speed, at least not for any   
   appreciable length of time.  In both cases, moving up and moving down,   
   it will first accelerate and then decelerate.  (It MUST accelerate then   
   decelerate; it could move at constant speed in between, but probably   
   doesn't since this would, for a given comfortable acceleration, increase   
   the travel time.)   
      
   In fact, the difference between your real weight (i.e. that measured at   
   rest with respect to the Earth) and what you measure in the elevator is   
   an indication of the acceleration.  (Note that many electronic scales do   
   not update the display in real time, but rather display a number once   
   the object has been weighed and not update this afterwards, even if the   
   weight changes, unless one first removes the weight from the scales,   
   resets them, etc.)   
      
      
   [[Mod. note -- For a short trip I would expect an elevator to accelerate   
   and then decelerate.  For a long trip I would expect an elevator to   
   accelerate until it reaches its design-rated maximum speed, then move   
   at a roughly constant velocity for a while, then decelerate.   
   -- jt]]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)