>>> MJ:
>>>
>>> Then look at your own drawing, which is correct, do you observe a rotation
>>> of
>>> the wheel _wrt its hub_?
>>
>> HV:
>> I observe the Sun going around the Earth and can represent this observation
>> with a drawing. However the drawing does not prove that the Earth is not
>> revolving about the Sun.
>
> MJ:
> But you can assert that the Sun and the Earth have a _relative_ motion can't
> you?
Yes, but my point was that a model of a motion is just a model of a motion,
it is not the motion itself.
>> HV:
>> Similarly, the Earth-wheel drawing does not prove
>> that the wheel is not rotating wrt to its hub.
>
> MJ:
> It is however clear that there is no _relative_ motion of the wheel wrt its
> hub. If you make pencil marks they will stay aligned.
Yes, but I would prefer to state it this way:
there is no _indication_ of motion of the wheel wrt its hub when the pencil
mark test is used. (This test can be done on the actual wheel too.)
>>> MJ:
>>> About your other experiment with a turntable if you want to draw conclusions
>>> wrt the Earth-wheel system don't forget the turntable should be rotating at
>>> _constant angular velocity_ both BEFORE and AFTER the brake is released,
>>> like
>>> the Earth in the Earth-wheel system. This is not what you said you did ("if
>>> I
>>> swivel the turntable 90 (or by any amount) _after_ the brake is released")
>>
>> HV:
>> A non-rotating turntable wrt to the ground has a constant angular
>> velocity of zero so I don't see why your particular conditions
>> are essential.
>
> MJ:
> Zero is fine by me, it's indeed constant, but then why use a turntable if it's
> not for rotating it?
As a test of my prediction.
> Besides you have lost me with that turntable digression, let's refocus on the
> original Earth and wheel system shall we? Do you still contend something
> (spoke tension?) will change after you release the brake from your original
> wheel on the Earth's equator?
>
> Before you answer, ask yourself, will it change again when you re-apply the
> brake? And then again when you re-release it?
>
Yes, the tension will vanish and then reappear. BTW a change in tension
might be easier to detect in the rim of the wheel. Repeating this process
many times would also generate heat.
Harry
