Op 17/09/2023 om 10:26 schreef Luigi Fortunati:
> wugi il 10/09/2023 08:37:40 ha scritto:
>>> A simple and clear example is the following.
>>>
>>> If observer B1 stands on the carousel, he sees the earth rotate a full
>>> 360 degrees in 5 seconds and sees the carousel stationary.
>>>
>>> Instead, observer A on the ground sees the carousel rotate 360 degrees
>>> in 5 seconds and sees dry land.
>>>
>>> One sees one thing, the other sees another: can both be real? Obviously
>>> not.
>>
>> No indeed, "obviously" there are only appearances.
>>
>>> If what observer A sees is real, what observer B1 sees can only be
>>> apparent.
>>>
>>> In fact, if the Earth really rotated at that angular velocity, it would
>>> shatter!
>>
>> Would it? You forget that with Earth, the whole universe is rotating
>> around B1, so that ultimately it is only B1 who is feeling the "real"
>> rotational force acting upon them, from Earth + Universe.
>
> I am so naive that I have always believed that the man on the in
> movement carousel feels the rotational force of the carousel and not
> that of the Earth + Universe.

(A late one). He feels the reaction force by Earth+Universe upon the
carousel's rotational action, transmitted through the carousel's
foundation and its own stiffness.
Compare with the water in the bucket, which doesn't feel the bucket's
swinging action, but rather the reaction upon the bucket by the rope, by
the hand, by the person swinging the bucket around, by the floor
retaining his feet, by Earth, ...

--
guido wugi

wugi il 04/04/2024 23:24:16 ha scritto:
>> I am so naive that I have always believed that the man on the in
>> movement carousel feels the rotational force of the carousel and not
>> that of the Earth + Universe.
>
> (A late one). He feels the reaction force by Earth+Universe upon the
> carousel's rotational action, transmitted through the carousel's
> foundation and its own stiffness.

What does the reaction force of the Earth+Universe to the rotating
action of the carousel have to do with the man on the carousel?

The man on the spinning carousel acts-reacts only with the carousel,
not with the Earth+Universe!

> Compare with the water in the bucket, which doesn't feel the bucket's
> swinging action, but rather the reaction upon the bucket by the rope, by
> the hand, by the person swinging the bucket around, by the floor
> retaining his feet, by Earth, ...

Here too, the only force that the water in the bucket feels is the
force of friction with the walls of the bucket and not that of the
hands, the rope or the Earth+Universe.

Luigi Fortunati

Op 8/04/2024 om 8:54 schreef Luigi Fortunati:
> wugi il 04/04/2024 23:24:16 ha scritto:
>>> I am so naive that I have always believed that the man on the in
>>> movement carousel feels the rotational force of the carousel and not
>>> that of the Earth + Universe.
>>
>> (A late one). He feels the reaction force by Earth+Universe upon the
>> carousel's rotational action, transmitted through the carousel's
>> foundation and its own stiffness.
>
> What does the reaction force of the Earth+Universe to the rotating
> action of the carousel have to do with the man on the carousel?
>
> The man on the spinning carousel acts-reacts only with the carousel,
> not with the Earth+Universe!
>
>> Compare with the water in the bucket, which doesn't feel the bucket's
>> swinging action, but rather the reaction upon the bucket by the rope, by
>> the hand, by the person swinging the bucket around, by the floor
>> retaining his feet, by Earth, ...
>
> Here too, the only force that the water in the bucket feels is the
> force of friction with the walls of the bucket and not that of the
> hands, the rope or the Earth+Universe.

Better back to your drawing board. Litterally.
Try to draw all intervening action/reaction pairs and check if you
haven't sent some force to "nowhere" ;)

--
guido wugi

wugi il 09/04/2024 09:00:40 ha scritto:
> Better back to your drawing board. Litterally.
> Try to draw all intervening action/reaction pairs and check if you haven't sent some force to "nowhere" ;)

Here is the drawing:
https://www.geogebra.org/m/tecb3dkw

For me, only the two blue and red forces act between man and the carousel; and nothing else.

For you?

Luigi Fortunati