Rate of fall depends on rotation?

[haruspex]

eventually were able to contradict me

What statement of yours do you think @jbriggs444 contradicted? Seems to me he went to a lot of trouble to put your idea

wouldn't the angular momentum in a wheel cause the Earth's rotation to slow slightly

on a firm foundation and demonstrated that while valid the effect is negligible in the extreme.

If you are complaining that he did not consider this part of your concept

and thus transfer the centripetal force that used to be distributed across the earth, right into the wheel?

that would be because he had no idea what you mean by it. And neither do I.

The centripetal force is not a property of the earth; it is the force necessary to keep the mass at constant radius in its motion around the earth’s axis. If the Earth were still and the mass were sliding frictionlessly around the equator once a day the centripetal force required to make it do that would be the same.

If I still have not grasped what cause you have for dissatisfaction with the responses you have had then I can only ask that you provide a more comprehensible description.

 

[jbriggs444]

You went through all these calculations and eventually were able to contradict me by a tiny tiny amount

Your claim was that the result was a significant upward force. In fact, the result is a tiny increase in downward force. The calculation was intended only to show that the increase in downward force was tiny, tiny, tiny.

By the way, centripetal force is proportional to angular momentum, and angular momentum is conserved, so how could centripetal forces just disappear?

Like @haruspex, I have great difficulty making sense of the argument you are trying to make with this remark.

Let us start with the easy piece: Is centripetal force proportional to angular momentum?

As it stands, such a claim is not specific enough to mean anything. So let us make it specific. We imagine a large rigid, rotating body floating in space. Attached to this body is a small object. The mass, mass distribution, size and shape of the large body is fixed. Its rotation rate is unknown. The mass of the object is fixed. We ask: "How much centripetal force is required to hold the object in place"?

If the mass of the object is $m$ the radius of the large body is $r$ and its rotation rate is $\omega$ then the required centripetal force is given by $F=mω^2r$.

Meanwhile, the angular momentum of the large body is given by its moment of inertia $I$ multiplied by its rotation rate. So the angular momentum is given by $L=I\omega$

Is $I\omega$ directly proportional to $m\omega^2r$? No. It is not. The one is linear in rotation rate. The other is quadratic.

That is the least of the problems with the argument you are trying to make. The other problems are worse.

 

[rzyn]

Well the thing is I think the weight loss is there but can't be found algebraically.

Plus I think because angular momentum is conserved centripetal force toward the center of the system must remain constant.
I think everyone for their input though. It is helpful, although I think it contains subtle erroneous assumptions.

 

[jbriggs444]

Well the thing is I think the weight loss is there but can't be found algebraically.

Plus I think because angular momentum is conserved centripetal force toward the center of the system must remain constant.
I think everyone for their input though. It is helpful, although I think it contains subtle erroneous assumptions.

You are free to think what you like. The truth is otherwise.

 

[rzyn]

Well you took the time to calculate the slowing of the Earth's rotation and a gain in weight around the Earth so small it doesn't matter. Don't you think at orders of magnitude so small you can say an effect doesn't matter, tidal effects would be of comparable magnitude or larger?

You took the time to calculate a result that fits your narrative or a point you want to make, expressing a result so small it "doesn't matter." But you ignore tidal effects without actually doing any calculations because you dismiss any effects that might resemble UFO-ish propulsion because you believe a priori that all such things are impossible.

You haven't done a side-by-side comparison that shows weight loss from tidal effects always being more negligible than another negligible.

I don't see why you have taken the time to show that all objects would get infinitesimally heavier without even addressing a comparison with a weight-loss effect on the Ferris wheel itself.

While I don't doubt that you've expressed truth, you've also omitted a truth which would counteract a truth you included.

So I'm left with something true, or not-false in itself at least, and an answer that you've expressed as a final, but with an a priori dismissal of any opposing effect.

You can make arguments any way you like and say they're the truth, but that doesn't mean they're thorough and unbiased and with all effects given equal treatment for their actual determined order of magnitude.

I appreciate it for its side of the story, though.

 

[jim mcnamara]

Thread closed, we are getting into speculation. Pf does not support that.