For me moon not rotate because always point toward me, bucket dont rotate in right case from ground frame,bucket dont rotate in left case in relation to G-room frame...etcA.T. said:
Proper acceleration, the kind you can measure with an accelerometer, is not.John Mcrain said:
Neither frame is "more true". Both will agree on direct observables (e.g. are there forces being applied to the water, or if the bucket rotating with respect to the lab). They may interpret these things differently ("rotating", for example, might mean in the invariant sense where there are detectable forces, or it might mean "rotating relative to me", which might or might not mean in the measurable sense and definitely depends on what frame you are using.).John Mcrain said:
Ibix said:
Not more true, but simpler with flatter water surface.John Mcrain said:
Any two frames will always agree on all direct observables. Frames of reference are conjured with paper and pencil. They are creations of the mind. They can never have physical effects.John Mcrain said:
Is roatation of bucket direct observables?jbriggs444 said:
I would say whether something is rotating or not is determined by whether or not it's feeling a centripetal force. That is a direct observable and something all frames will agree on.John Mcrain said:
I only say ,for my right case ,bucket rotate in relation to G-room, but not rotate in relation to ground.Ibix said:
And all frames can agree on those measurements.John Mcrain said:
No they don't. They differ on whether the buckets ate rotating relative to themselves, but that's because they have different definitions of "themself", not because they have different results.John Mcrain said:
They could just look. There can be only one answer. It is well known for a bucket bolted to the floor of the turntable, but harder to calculate for a bucket on a turntable on a turntable, in part because it likely depends on things like the frictional forces between the water and the bucket.John Mcrain said:
You mean if friction is zero between water and bucket walls, water will contiue to spin for some time after G room is stoped, for right case?Ibix said:
I mean in general. You'll note A.T.'s analysis explicitly talks about "lag" and "tending to" his solution.John Mcrain said:
As for the why-part: We don't really know. Mach's principle is the idea that inertial frames are related to the large-scale distribution of matter in the universe.John Mcrain said:
Is it just an empty bucket? If the bearing is such that no moments can be applied to the bucket, its angular momentum will remain constant in inertial frames.John Mcrain said:
So during rotation of G-room, bucket will keep same orientation in relation to ground(inertail,stationary frame), but it will rotate in relation to G-room(rotating frame). So this is basicaly same case as my "right case".A.T. said:
Just like we receive CMB that was emitted by matter which is now very far away, we might also be affected by this matter in terms of inertia.vanhees71 said:
If an empty bucket starts at rest in the ground frame, and is mounted on a vertical friction-less axis though its CoM, yes.John Mcrain said:
Because water will complicate things, It can move relative to the bucket and thus shift the CoM.John Mcrain said:
the CMB is the remnant of electromagnetic thermal radiation within the soup of hot and dense charged matter, which was very close to thermal equilibrium, in the early universe. It decoupled from the matter about 400'000 years after the big bang when atoms were formed and matter got electrically neutral.A.T. said:
It's Newtonian mechanics, not rocket science. It works quite well. Conservation of angular momentum is well confirmed experimentally. Galileo did a lot of the experimental work.John Mcrain said:
What physics field is consider the hardiest? Does this frames questions what we are talking here is valid in micro world, atom and smaller particels?jbriggs444 said:
You should not feel stupid. Instead, enjoy the learning and keep asking questions. We all had to learn this stuff sometime...John Mcrain said:
