Strange Posted October 13, 2014 Posted October 13, 2014 Is electro- motive force ever considered when considering the rotation? I'm sure more than one person has done a quick mental or back-of-the-envelope calculation and then realised there is nothing to consider. (The result being approximately zero.)
Relative Posted October 13, 2014 Author Posted October 13, 2014 I'm sure more than one person has done a quick mental or back-of-the-envelope calculation and then realised there is nothing to consider. (The result being approximately zero.) Thank you, Can I ask some more questions about the Earth in this thread rather than opening another?
Janus Posted October 13, 2014 Posted October 13, 2014 Ok, thank you, so you are saying the Earth and the Moon are a couple and there is a torque involved? Are you saying that forces with no linkage and based on a connection of forces, that there is an energy linkage that creates torque? The force that transfers angular angular momentum to the Moon is gravity. Here is the basic mechanism: The Moon raises tides on the Earth, which are seen as tidal bulges. Since the Earth rotates faster than the Moon orbits, it rotates with respect to these bulges. Friction between the rotating Earth and the bulges tries to drag the bulges along with the rotating Earth. Meanwhile, the Moon's gravity works to keep the bulges aligned with itself. This "tug of war" results in the bulges not rotating with the Earth, but also not staying aligned with the Moon. The near bulge tends to lead the Moon a slight bit. Since the mass in the bulge is always ahead of the Moon in it's orbit, it tend to pull forward on the Moon, which tries to speed up the Moon. Do to the complexities of orbital mechanics which we will not go into here, this causes the Moon to climb to a higher orbit. Meanwhile, the interaction between the rotating Earth and bulges tends to slow the Earth's rotation. Now not all of the rotation lost by the Earth is transferred to the Moon. The friction between tidal bulges and Earth also generate heat and a portion of the energy lost to slowing rotation goes into this heat, which is radiated out into space.
Relative Posted October 13, 2014 Author Posted October 13, 2014 The force that transfers angular angular momentum to the Moon is gravity. Here is the basic mechanism: The Moon raises tides on the Earth, which are seen as tidal bulges. Since the Earth rotates faster than the Moon orbits, it rotates with respect to these bulges. Friction between the rotating Earth and the bulges tries to drag the bulges along with the rotating Earth. Meanwhile, the Moon's gravity works to keep the bulges aligned with itself. This "tug of war" results in the bulges not rotating with the Earth, but also not staying aligned with the Moon. The near bulge tends to lead the Moon a slight bit. Since the mass in the bulge is always ahead of the Moon in it's orbit, it tend to pull forward on the Moon, which tries to speed up the Moon. Do to the complexities of orbital mechanics which we will not go into here, this causes the Moon to climb to a higher orbit. Meanwhile, the interaction between the rotating Earth and bulges tends to slow the Earth's rotation. Now not all of the rotation lost by the Earth is transferred to the Moon. The friction between tidal bulges and Earth also generate heat and a portion of the energy lost to slowing rotation goes into this heat, which is radiated out into space. Thank you , to clarify my understanding, if the moon was to increase its gravity ten fold, the bulge would become a giant Tsunami?
Robittybob1 Posted October 13, 2014 Posted October 13, 2014 I understand speed of a spin can be altered by aerodynamics on Earth in an atmosphere, but Newtons law states that an object in space that has momentum, whether it be linear or rotational should not slow unless an external acting force opposes it. Ok , so what external force acts on the moon? Gravity - if the gravitational force is ahead of the object, gravity will make it speed up, but in the Moon's case the Earth gives it more orbital energy (it is actually slowed in tangential velocity but since it orbits at a larger radius in fact there is more Gravitational potential energy in the system). It took me a while to understand how it all fits together.
Relative Posted October 13, 2014 Author Posted October 13, 2014 Gravity - if the gravitational force is ahead of the object, gravity will make it speed up, but in the Moon's case the Earth gives it more orbital energy (it is actually slowed in tangential velocity but since it orbits at a larger radius in fact there is more Gravitational potential energy in the system). It took me a while to understand how it all fits together. The moon has gravity, it is weak but it has gravity, the force imposed by gravity of the earth is equal to the force imposed by the moon , er and the orbit should be based on centripetal acceleration, but has mentioned earlier, the moon is tidal locked, so the force imposed of the earths gravity is altered by the force imposed by the sea, oceans, etc. If i understood that correctly. However the moon is moving away, extending its radius, so either the moon is losing its hold on the earth or vice versus?
Robittybob1 Posted October 13, 2014 Posted October 13, 2014 Thank you , to clarify my understanding, if the moon was to increase its gravity ten fold, the bulge would become a giant Tsunami? The only way that can happen is when the Moon was a lot closer. They reckon after it formed it was something like 50,000 km, rather than the 350,000 it is now. So the 7 times as close and gravitational force is proportional to 1/r^2 so it was 2^7 times as strong then. That is 128 times as strong.
studiot Posted October 13, 2014 Posted October 13, 2014 Gravity - if the gravitational force is ahead of the object Can you explain that in the light of Newton's Law of Gravitation?
Robittybob1 Posted October 13, 2014 Posted October 13, 2014 The moon has gravity, it is weak but it has gravity, the force imposed by gravity of the earth is equal to the force imposed by the moon , er and the orbit should be based on centripetal acceleration, but has mentioned earlier, the moon is tidal locked, so the force imposed of the earths gravity is altered by the force imposed by the sea, oceans, etc. If i understood that correctly. However the moon is moving away, extending its radius, so either the moon is losing its hold on the earth or vice versus? It has nothing to do with being tidally locked. The Moon does not only bulge the sea etc but also the land and it is the land bulge that is most significant in the exchange of momentum. The whole thing is hard to understand but get a weight and tie a string to it and make it circulate around you and discover what you have to do to make it spin faster. You'll find you have to pull it ahead of the center. And that is what is happening to the Moon.
Relative Posted October 13, 2014 Author Posted October 13, 2014 It has nothing to do with being tidally locked. The Moon does not only bulge the sea etc but also the land and it is the land bulge that is most significant in the exchange of momentum. The whole thing is hard to understand but get a weight and tie a string to it and make it circulate around you and discover what you have to do to make it spin faster. You'll find you have to pull it ahead of the center. And that is what is happening to the Moon. Thank you , and it is easy to understand what happens between the forces and why it bulges, mass attracted to mass etc, but I still consider that if the moon become charged or thermodynamic increase or similar, then it would be repelled away, in another words, if the moon became an equilibrium to the earth magnetic field which expands into space, but weakens at distance, the earths field direction would be the moons direction, outward?
Robittybob1 Posted October 13, 2014 Posted October 13, 2014 Thank you , and it is easy to understand what happens between the forces and why it bulges, mass attracted to mass etc, but I still consider that if the moon become charged or thermodynamic increase or similar, then it would be repelled away, in another words, if the moon became an equilibrium to the earth magnetic field which expands into space, but weakens at distance, the earths field direction would be the moons direction, outward? I can't relate to what you are saying sorry. Where would this charge come from?
Relative Posted October 13, 2014 Author Posted October 13, 2014 I can't relate to what you are saying sorry. Where would this charge come from? The moon absorbs and reflects the suns energy, it has no atmosphere to absorb it, it is, forgive the wording , a sitting duck. I cant go off thread to much grrrr.... electron v electron is always repel, and also this - Paramagnetism is a form of magnetism whereby certain materials are attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field. But I will get the thread closed if i continue so sorry.it is a earth thread, I need to ask about the core, and the magnetic bearing, been magna, and magnetism releasing electrons through the earth, giving thermodynamic increase by struggling to escape .
Robittybob1 Posted October 13, 2014 Posted October 13, 2014 The moon absorbs and reflects the suns energy, it has no atmosphere to absorb it, it is, forgive the wording , a sitting duck. I cant go off thread to much grrrr.... electron v electron is always repel, and also this - Paramagnetism is a form of magnetism whereby certain materials are attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field. But I will get the thread closed if i continue so sorry.it is a earth thread, I need to ask about the core, and the magnetic bearing, been magna, and magnetism releasing electrons through the earth, giving thermodynamic increase by struggling to escape . It is all related but you seem to struggle with getting your ideas across. I have done some great work on those very topics, so you might have to start another thread on the Earth's Core.
Strange Posted October 13, 2014 Posted October 13, 2014 magnetism releasing electrons through the earth Which doesn't happen.
Relative Posted October 13, 2014 Author Posted October 13, 2014 Which doesn't happen. The earths magnetic field contains no electrons?
Strange Posted October 13, 2014 Posted October 13, 2014 The earths magnetic field contains no electrons? The magnetic field does not contain electrons. It is probably generated by electrons.
Relative Posted October 13, 2014 Author Posted October 13, 2014 The magnetic field does not contain electrons. It is probably generated by electrons. Interesting, i think i need to start to a core thread, If there is electrons in the core generating a field, and I need to ask about Faraday and magnetic motive force, movement of a magnet in a copper coil makes electrons.
pzkpfw Posted October 13, 2014 Posted October 13, 2014 Interesting, i think i need to start to a core thread, If there is electrons in the core generating a field, and I need to ask about Faraday and magnetic motive force, movement of a magnet in a copper coil makes electrons. Moves, not makes.
Relative Posted October 13, 2014 Author Posted October 13, 2014 (edited) Moves, not makes. Yes of cause how stupid of me , I should consider more what I write. When I already mention motive force. Edited October 13, 2014 by Relative
MigL Posted October 14, 2014 Posted October 14, 2014 Why do you guys keep engaging him ? He's obviously not even considering your learned replies. He makes statements like... 'Photons spin. Wheels on cars spin. Can you imagine how fast we could drive on the sun ?' And by engaging him, the threads go on for several pages before they are invariably locked. He's managed to lock more threads in the last couple of days than anyone else in the last couple of years. By engaging him, you give legitimacy to his ignorant ( as in lacking knowledge ) ramblings, and may be doing more harm to new members wishing to learn some real science than if you ignore him, hope he goes away, and buys an elementary physical science textbook ( Gr. 10 level should do ). He's like a classic drug addict, there's nothing we can do, he has to want to help himself.
pzkpfw Posted October 14, 2014 Posted October 14, 2014 (edited) I do wonder. On a similar site he's been posting with the name "trollery" (and recently got suspended for a bit). (What happens on other forums is their business, so I'm not suggesting anything for here.) I see him as someone who has learned that 1 + 1 = 2, and then skips right to telling people how the Pythagoras Theorem is supposed to work. Unless it's deliberate ... Edited October 14, 2014 by pzkpfw
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