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Gravity at the center of the Earth?
21 years 9 months ago #4897
by Jeremy
Replied by Jeremy on topic Reply from
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
The splitting of a sphere into two equal masses can be done in many ways. Have you considered dividing the sphere into an inner and outer sphere of equal mass? Doing it this way it the inner sphere is attracted to the outer sphere and visa-versa. Would the force of gravity would be shifted from the center of mass?
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Sorry, the center of mass stays in the center. You are forgetting to sum the effects of all the individual atoms attracting each other. The center of mass of a sphere is its center and so is that of a hollow sphere.
The splitting of a sphere into two equal masses can be done in many ways. Have you considered dividing the sphere into an inner and outer sphere of equal mass? Doing it this way it the inner sphere is attracted to the outer sphere and visa-versa. Would the force of gravity would be shifted from the center of mass?
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Sorry, the center of mass stays in the center. You are forgetting to sum the effects of all the individual atoms attracting each other. The center of mass of a sphere is its center and so is that of a hollow sphere.
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21 years 9 months ago #4525
by Jim
Replied by Jim on topic Reply from
The mass center is unchanged-the gravity center shifts. In the current standard model of a sphere both the mass center and gravity center are in the same position. I am modeling the two centers at different locations.
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21 years 9 months ago #4527
by Jeremy
Replied by Jeremy on topic Reply from
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
The mass center is unchanged-the gravity center shifts. In the current standard model of a sphere both the mass center and gravity center are in the same position. I am modeling the two centers at different locations.
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I assume that what you are calling the "gravity center" is the mathematical point at which we can say gravity is attracting things toward. Like the barycenter in an orbit it is a fictitious point used for convenient visualization. In the model you described there are trillions and trillions of gravity sources that are to be considered. I guess I'm not clear on what you mean by "gravity center" other than it being the apparent point of attraction. Could you clarify?
The mass center is unchanged-the gravity center shifts. In the current standard model of a sphere both the mass center and gravity center are in the same position. I am modeling the two centers at different locations.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I assume that what you are calling the "gravity center" is the mathematical point at which we can say gravity is attracting things toward. Like the barycenter in an orbit it is a fictitious point used for convenient visualization. In the model you described there are trillions and trillions of gravity sources that are to be considered. I guess I'm not clear on what you mean by "gravity center" other than it being the apparent point of attraction. Could you clarify?
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21 years 9 months ago #4532
by tvanflandern
Replied by tvanflandern on topic Reply from Tom Van Flandern
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>[Jim]: The splitting of a sphere into two equal masses can be done in many ways. Have you considered dividing the sphere into an inner and outer sphere of equal mass? Doing it this way it the inner sphere is attracted to the outer sphere and visa-versa. Would the force of gravity would be shifted from the center of mass?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I agree with Jeremy that your use of "gravity center" is undefined and unclear. But perhaps it will help to clarify it in your own mind to see that your above example is based on an incorrect supposition.
The inner sphere attracts the outer sphere, as it does anything in the universe outside itself. However, gravity force inside the inner sphere goes to zero, as explained before. And quess what? So does gravity inside the outer sphere! The interior of any uniform spherical shell has zero gravitational force everywhere in its interior.
It therefore follows that the outer spherical shell does not attract the inner one. This asymmetry is part of the reason the outer shell applies pressure (weight) on the inner one, but not vice versa. -|Tom|-
I agree with Jeremy that your use of "gravity center" is undefined and unclear. But perhaps it will help to clarify it in your own mind to see that your above example is based on an incorrect supposition.
The inner sphere attracts the outer sphere, as it does anything in the universe outside itself. However, gravity force inside the inner sphere goes to zero, as explained before. And quess what? So does gravity inside the outer sphere! The interior of any uniform spherical shell has zero gravitational force everywhere in its interior.
It therefore follows that the outer spherical shell does not attract the inner one. This asymmetry is part of the reason the outer shell applies pressure (weight) on the inner one, but not vice versa. -|Tom|-
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21 years 9 months ago #4536
by Jim
Replied by Jim on topic Reply from
The details can be clarified much better with a two sphere disection than a two hemisphere chop. The difference is in the details. With tow hemispheres you have little to work with. Two equal mass spheres with very different other properties can perhaps aid in unlocking the dynamic mysteries that clearly exist in spheres ans other structure.
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21 years 9 months ago #4665
by xainabbas
Replied by xainabbas on topic Reply from Zain Abbas
Hello,
I have someting confusive in my mind about the Gravity. I m from Pakistan can u tell me what is major source of the Gravity, like sun is the major source of light for this earth. and what I think about how we are stucked to the earths crust is the anticlockwise motion of this earth and all forces due to Earths anti motion let us to stand on the ground.
If this is not clearify you then let me know I'll try to clear it more.
I'll be very thankful to you if u let me know that what the reality is...???
Thnx.
Zain Abbas
I have everything in mind so confusive about the natural facts.
I have someting confusive in my mind about the Gravity. I m from Pakistan can u tell me what is major source of the Gravity, like sun is the major source of light for this earth. and what I think about how we are stucked to the earths crust is the anticlockwise motion of this earth and all forces due to Earths anti motion let us to stand on the ground.
If this is not clearify you then let me know I'll try to clear it more.
I'll be very thankful to you if u let me know that what the reality is...???
Thnx.
Zain Abbas
I have everything in mind so confusive about the natural facts.
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