0

Passengers on a plane cannot feel the plane move when it's at cruise speed. Can the same reasoning be extended to earth's rotation to explain why we cannot feel it rotate even though it's rotating at a high angular velocity.

Roger V.
  • 58,522
Trevor Mugalu
  • 1

2 Answers2

1

Did you search on this site before asking? This has been asked and discussed many times before.

In a nutshell, any frame is only approximately inertial, so the question is only: can I treat it as inertial for the duration of my experience? For our everyday lives, yes. For something like a Foucault pendulum, no.

Miyase
  • 6,152
  • 21
  • 23
  • 37
0

If I may step outside of the angular momentum component of this question to examine briefly the part about inertial frames.

As mentioned, any frame is only approximately inertial, for the duration of the experience. But more than this, can you justifiably argue that within the limited space and time of the event of interest, these outside influences are simply negligible?

And, were you writing a thesis or dissertation, can you provide an acceptable definition of "negligible"? (I remember arguing with my dissertation chair for weeks about what could be considered "negligible".)

For example, within the time and space of a laser photon travelling from one end of the interior of a truck trailer to the other, we can safely presume the truck is essentially standing still, and by extension, the Earth. And so within that operational window of space-time, the frame is effectively inertial or even stationary.

However, as the space grows larger and/or the time frame longer, we start to put pressure on our definition of "negligible", which makes some instructors uncomfortable. This is why many textbook questions keep their conditions far far from the fuzzy boundary.

This is, in my professional academic opinion, a bit a of a disservice. This kind of inquiry is right there on the doorstep to something REALLY COOL.

Should this kind of discussion be ignored, lower division physics students might walk away with the impression that all of these definitions and equations are absolute, with hard boundaries, ignoring 2nd and 3rd order terms, and then grow up with rigid, polarizing, dogmatic attitudes that degrade the core heart of scientific thinking.

Point is, this kind of question is EXCELLENT for pulling students down into the way-cool nuanced complexity of scientific thinking.

Don't dismiss it! :)

ezfzx
  • 1