The elevator in free fall in the gravitational field is an inertial
reference system.
Is the elevator in free fall in the magnetic or electric field also an inertial reference system?
An even more general principal is that "free fall" means "fall without obstacles".
No one can deny that, in the most remote space far from all gravity,
a metal elevator falling towards an electromagnet is in "free fall".
And a metal robot in a metal elevator resting on an electromagnet
(without being able to look outside) cannot know if there is a motor
that is accelerating the elevator or if there is an electromagnet that
is attracting it towards the floor (principle of equivalence).
Luigi Fortunati il 23/01/2024 12:46:45 ha scritto:
Mikko il 21/01/2024 14:42:49 ha scritto:
The elevator in free fall in the gravitational field is an inertial
reference system.
Is the elevator in free fall in the magnetic or electric field also an >>>> inertial reference system?
That depends on the magnetic and electric properties of the elevator.
The elevator is metallic, the body in the elevator is the same metal as
the elevator.
The field is generated by an electromagnet.
Luigi Fortunati
[[Mod. note --
The general principal is that "free fall" means no non-gravitational
forces are acting.
An even more general principal is that "free fall" means "fall without obstacles".
[[Mod. note -- The general principal is that "free fall" means no
non-gravitational forces are acting.
An even more general principal is that "free fall" means "fall
without obstacles".
No one can deny that, in the most remote space far from all gravity,
a metal elevator falling towards an electromagnet is in "free fall".
Tom Roberts il 27/01/2024 09:23:06 ha scritto:
No one can deny that, in the most remote space far from allNot true: every physicist would deny that, because the
gravity, a metal elevator falling towards an electromagnet is in
"free fall".
electromagnet exerts an electromagnetic force on the elevator,
making it NOT be in freefall.
Gravity also exerts a force on the elevator.
There is a well that reaches exactly the center of the Earth and there
are two elevators: one stationary at the bottom of the well (elevator A)
and the other in free fall (elevator B).
Are the two elevators inertial reference systems of the same type or is
one reference system more inertial than the other?
Luigi Fortunati
Mikko il 06/02/2024 09:26:51 ha scritto:
There is a well that reaches exactly the center of the Earth and there
are two elevators: one stationary at the bottom of the well (elevator A) >>> and the other in free fall (elevator B).
Are the two elevators inertial reference systems of the same type or is
one reference system more inertial than the other?
The elevator B is moving so it is affected by air resistance and other
friction effect. It also meets the fast varying tidal effects from
density variations in the matter around the well.
If these effects can be kept small enough that they cannot be detected
in B then B is in free fall.
If the well is deep enough that the elevator A does not touch its
bottom the elevator A is in free fall.
If both elevators are in free fall in the above sense then there is
no detectable difference in the conditions inside of the elevator.
When the two elevators collide neither of the elevators is no longer
in free fall.
You're twisting everything I wrote.
I wrote that the well ends at the center of the Earth (the bottom of the
well is at the center of the Earth).
That elevator A is STOPPED at the bottom of the well and, therefore, is stationary at the center of the Earth.
That elevator A stays still not because the bottom of the shaft prevents
it from falling but because (at the center of the Earth) there is no
force of gravity and no space-time curvature that sets it in motion to
go somewhere: it stays still because nothing and no one pushes him
somewhere.
That elevator B is in free fall without friction and without resistance.
That elevator B is falling (in free fall) towards elevator A which it
will collide with in the future.
I would like to know *now* (before their clash) if they are both
inertial reference systems and if they are in the same way or if one is
more inertial than the other.
I hope I have been clear.
Luigi Fortunati
Mikko il 06/02/2024 15:26:36 ha scritto:
On 2024-02-06 12:21:12 +0000, Luigi Fortunati said:
Mikko il 06/02/2024 09:26:51 ha scritto:
If the well is deep enough that the elevator A does not touch its
bottom the elevator A is in free fall.
I wrote that the well ends at the center of the Earth (the bottom of the >>> well is at the center of the Earth).
That elevator A is STOPPED at the bottom of the well and, therefore, is
stationary at the center of the Earth.
The elevator at the bottom is not inertial. If the well were deeper the
elevator could but the bottom prevernts that.
The bottom doesn't impede anything and, to prove it, in my new
animation https://www.geogebra.org/m/mdymaxsb I totally eliminate it.
In free fall, can you go anywhere freely or are there constraints that prevent this?
Of course you can't fall straight up and you can't fall sideways.
In free fall, can you go anywhere freely or are there constraints
that prevent this? Of course you can't fall straight up and you
can't fall sideways.
In free fall you can only go in one direction (the vertical one) and
in only one versus (downward).
The elevator (in free fall) and everything inside it are forced to
fall (always) vertically and (always) downwards.
So there is a constraint.
And, in free fall, can one move in a straight and uniform motion?
No, in free fall the motion is always accelerated.
So why call it "free fall" and not "forced fall"?
[Moderator] That is, the gravitational force on a body with
inertial mass 2 kg is (a) precisely twice that on a body with
inertial mass 1 kg,
But (if I'm not mistaken) (a) also applies to the electromagnetic
force which, on a 2-gram body of any material, is exactly double
that on a 1-gram body of any material. Is that so?
The elevator in free fall in the gravitational field is an inertial
reference system.
Is the elevator in free fall in the magnetic or electric field also an inertial reference system?
Luigi Fortunati
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 342 |
Nodes: | 16 (2 / 14) |
Uptime: | 27:48:30 |
Calls: | 7,512 |
Calls today: | 9 |
Files: | 12,713 |
Messages: | 5,641,820 |
Posted today: | 2 |