From: sylvia@email.invalid   
      
   On 17/11/2022 9:01 pm, Luigi Fortunati wrote:   
   > Are tidal forces real or apparent?   
   >   
      
   That's the kind of question that can lead to fisticuffs in otherwise   
   polite physics circles.   
      
   They're as real as the gravitational force holding you down to the   
   ground, except that some would argue that there's no such thing as a   
   gravitational force, and that what's happening is that you're being   
   accelerated by the upwards force from the ground.   
      
   So to avoid physical violence in these situations, you need a very   
   precise definition of real versus apparent.   
      
   That said, tidal forces are not as unreal as the Coriolis force that   
   appears to be acting on a freely moving object when the observer is in a   
   rotating frame.   
      
      
   > Are tidal forces gravitational forces?   
   >   
   See above.   
      
      
   [[Mod. note -- An additional point is that tidal forces can do work:   
     https://en.wikipedia.org/wiki/Tidal_power   
   -- jt]]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)