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Quote from: Jaaanosik on 14/10/2020 16:39:55Three CD players would behave as one CD player if the axes are aligned and they spin in the same direction.No they would not, because the angular momentum would be three times higher.But it seems you have more or less answered the right questionQuote from: Jaaanosik on 14/10/2020 16:39:55The CDs would spin inside and the CD players would spin in the opposite direction in ideal conditions.The total net momentum would be 0.OK, so the total angular momentum would be zero.So, if you tapped on it like in the video, what would happen?(Imagine that the finger tapping it is moving at the same speed tangentially as the player so it doesn't impart a torque.)Do you agree that , because the overall angular momentum is zero, it will tumble and there will be no "gyroscope" effect?
Three CD players would behave as one CD player if the axes are aligned and they spin in the same direction.
The CDs would spin inside and the CD players would spin in the opposite direction in ideal conditions.The total net momentum would be 0.
Do we have an agreement that the system demonstrates different attributes, the system behaves differently due to the internal motion of inner parts even thought the total net angular momentum is the same before the external impulse?
Imagine I have two pairs of players taped together feet to feet so that (as long as the disk speeds are the same) the angular moment sum to zero.I set both disks in one pair spinning.I leave the other pair switched off.And, since I'm in zero gravity Ican just put the two pairs in front of me and watch them.They do nothing, because no (significant) external force is action on them.Imagine I tap both of the pairs on the corresponding corners.Do you think they will behave differently (because one of the pairs contains spinning things, and the other pair does not)?
If one is 'rigid' body and the other has moving parts, they have to behave differently.
They will behave differently.
(Am I The only one who worries about anyone in zero G who thinks that taping 3 CD players together at right angles is ter than taping them together with the axes aligned?)
Quote from: puppypower on 13/10/2020 15:18:02One observation that nobody has mentioned, is that the earth's core spins faster than the surface of the earth. This was discovered in 1996 but has been ignored by the status quo, since too much credit would have required a complete revision of current earth theory.BollocksThe theory actually predicted that the core spins faster in 1995.This was then measured in 1996.Quote from: puppypower on 13/10/2020 15:18:02If we accept this data as true, then we need to revise the earth sciences since no models anticipated this, Just not true." A 1995 model of Earth's dynamo predicted super-rotations of up to 3 degrees per year; the following year, this prediction was supported by observed discrepancies in the time that p-waves take to travel through the inner and outer core."From wikihttps://en.wikipedia.org/wiki/Inner_core_super-rotationThe rest of your post makes no more sense than would be expected, given that it's based on errors.
One observation that nobody has mentioned, is that the earth's core spins faster than the surface of the earth. This was discovered in 1996 but has been ignored by the status quo, since too much credit would have required a complete revision of current earth theory.
If we accept this data as true, then we need to revise the earth sciences since no models anticipated this,
The question I asked and tried to answer was, how does the observation that the core of the earth is spinning faster than the surface, impact the rest of earth science, all the way to global warming?
Can heat impact the rotation of the earth? If the core is driving the rotation, then the question becomes does heat increase reaction rate and thereby speed core rotation and the secondary affect this will cause?
And why hasn't the status quo altered the rest of the theory to accommodate the implication of a moon sized object within the earth spinning faster than the surface?
At the very least we now have a huge object creating viscoelastic friction, which creates heat, eddies, convection and a moving phase boundary.
The explanation for the core's higher rotation is supposedly based on the cooling of the fluid outer core. This causes this fluid iron material to contract into the solid inner core. Like the skating pulling in their arms, the angular momentum is conserved, so the result is faster spin.
The problem with this model is why isn't the surface and mantle contracting to fill in the space left behind by the contracting outer core?
Has anyone thought this through, and are surface observations consistent with these extras?
When a liquid changes phase into a solid, there is heat of fusion given off. Where is this extra heat going?
Mars does not rotate very fast
Has the surface water been commandeered to the iron core?
Quote from: Jaaanosik on 14/10/2020 21:26:11They will behave differently.I am really rather sure that they will not behave differently.
Quote from: Bored chemist on 14/10/2020 21:53:31Quote from: Jaaanosik on 14/10/2020 21:26:11They will behave differently.I am really rather sure that they will not behave differently.No, they will behave differently!
Quote from: Bored chemist on 14/10/2020 18:54:49Imagine I have two pairs of players taped together feet to feet so that (as long as the disk speeds are the same) the angular moment sum to zero.I set both disks in one pair spinning.I leave the other pair switched off.And, since I'm in zero gravity Ican just put the two pairs in front of me and watch them.They do nothing, because no (significant) external force is action on them.Imagine I tap both of the pairs on the corresponding corners.Do you think they will behave differently (because one of the pairs contains spinning things, and the other pair does not)?They will behave differently.Considering we are applying an external momentum, the distribution to all parts of these two systems is not going to be the same therefore they will behave differently.If one is 'rigid' body and the other has moving parts, they have to behave differently.I am not saying the external momentum will 'get lost', I am saying it will distribute through the system differently and therefore the systems will move (translate/rotate) differently.
Quote from: Jaaanosik on 15/10/2020 23:22:54Quote from: Bored chemist on 14/10/2020 21:53:31Quote from: Jaaanosik on 14/10/2020 21:26:11They will behave differently.I am really rather sure that they will not behave differently.No, they will behave differently!Jano, you really need to be more precise, since there is no context left to criticise.So what systems are you talking about (one running, one not presumably). What state are they in, and what force is being applied? Just force? Torque? In what way does the running system behave differently than the non-running one?I mean, I agree with you. The running one probably has a little yellow light on and has a display that counts the time where it is in the music, and the not-running one doesn't have these. I don't think you're talking about those kind of differences, but with a childish response like that, it's all I have to go on.So if you assert that it behaves differently, say how exactly, and if it can be shown to violate a known conservation law, you're probably very very wrong.
So, if you were right, a CD would be a very effective gyroscope, even lying on teh table before you started spinning it (and, indeed, for any practical speed, rotating it wouldn't make much difference).On the other hand, my contention is that the angular momentum of a composite body is the vector sum of the momenta of the components of a the body. Unless those are carefully aligned, they usually sum to zero.And so, for the pair of CD players, just like for the non rotating CD, there's no "gyroscope" effect.You should have answered my question about a box full of CD players.
When the CD players are ON then we need to consider the 'elasticity' of EM field of the motors.One CD will be accelerated and the other will be decelerated when we apply the same external momentum as per the image.
My post above shows what you missed.
We apply the external forces as per the image, in the CDs parallel plane.
This is what I meant when I said: "The external momentum will distribute through the system differently and therefore the systems will move (translate/rotate) differently."