Are fictitious forces necessary to solve certain problems?

In summary, it can be handy to ignore the Earth's rotation and simply work with the effective g', instead of accounting for g'=g+a; and similarly it may be handy to use Coriolis forces and so on for weather predictions. Nevertheless, I assume that calculations with fictitious forces can always be reconverted in similar calculations without them.
  • #71
harrylin said:
What you call "fictitious force", others might call an artifact or correction term for non-inertial motion; and although mathematically the value will be the same, conceptually that is very different. So, it's not merely a matter of labels, but also of concepts. Perhaps that is why some teachers can get very upset when others call those correction terms "fictitious forces". :wink:
It doesn't matter if you also call it an "artifact" or a "correction term" or "Bob's uncle". It fits the definition of a fictitious force therefore it is a fictitious force, regardless of what other definitions it also fits.

Your argument here is like saying that a square is not a rectangle because other people will call it a square, and it isn't just a matter of labels since squares and rectangles are conceptually different, and some people get upset if you call a square a rectangle. It is an invalid argument. A square is a rectangle because it fits the definition of a rectangle, and the extra terms in the equations of motion in a non-inertial frame are fictitious forces because they fit the definition of a fictitious force.

harrylin said:
Anyway, as commonly textbooks do not use the fictitious force concept for those derivations, I take it that my question has been sufficiently answered.
Kindly back up this claim with a reference. All textbooks should use fictitious forces, either as a part of the derivation or as an end result of the derivation. If they do not, then they are in error. Obviously, they may not discuss their use of fictitious forces, but they must use them.
 
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  • #72
DaleSpam said:
[..]
Kindly back up this claim with a reference. All textbooks should use fictitious forces, either as a part of the derivation or as an end result of the derivation. If they do not, then they are in error. Obviously, they may not discuss their use of fictitious forces, but they must use them.

Already given and commented in post #65; similar to basic textbooks that discuss Coriolis acceleration etc. without introducing the fictitious force concept. It was in that sense that I intended my question, which now has been answered to my satisfaction.
 
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  • #73
harrylin said:
Already given and commented in post #65; similar to basic textbooks that discuss Coriolis acceleration etc. without introducing the fictitious force concept. It was in that sense that I intended my question, which now has been answered to my satisfaction.
Coriolis acceleration and coriolis force are one and the same thing, sans a factor of mass. You are playing a stupid semantics game, Harald.

Thread closed.
 

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