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Gabriele Pinna
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What kind of force acts in the centre of the Earth ? What is the intensity ?
If you assume the Earth has a spherically symmetric mass distribution, the gravitational force of the Earth on an object at the center of the Earth would be zero.Gabriele Pinna said:What about the gravitational force acts by the Earth ?
Normal to what?ProfuselyQuarky said:Could you say normal force is acting on the center, or no?
A "normal" force is usually a force between an object and some supporting surface (and normal to that surface). What did you have in mind?ProfuselyQuarky said:Could you say normal force is acting on the center, or no?
Normal meaning orthogonal. I didn’t know there had to be a supporting surface.Doc Al said:and normal to that surface
I had that in mind. I was wondering if that was correct or incorrect. I guess it's incorrect?ProfuselyQuarky said:If we’re talking about a single point in the center of the earth, would that mean that normal force is acting on the point in all directions?
90 degree angle relative to what? Any direction looks the same, there is no normal force because the concept does not even make sense.ProfuselyQuarky said:Normal force meaning any force acting on something at a ##90^{\circ}## (right) angle. If we’re talking about a single point in the center of the earth, would that mean that normal force is acting on the point in all directions?
That is pressure in a fluid, not normal force.ProfuselyQuarky said:would that mean that normal force is acting on the point in all directions?
That’s what I was asking about. Since the 90 degrees would not be relative to any specific surface, I thought that would mean that the force could be acting on the point in all directions.mfb said:90 degree angle relative to what?
Okay, fine. The idea is jargon.mfb said:the concept does not even make sense.
I see . . . thanks for the explanation :)A.T. said:That is pressure in a fluid, not normal force.
I figured that's what you were really inquiring about -- and teasingly avoided that in my first answer. The Doc made good on that, but perhaps it's good to elaborate a bit more. For ##1/r^2## laws such as Newton's law of gravity ( and following ) and Coulomb's law one can derive Gauss' theorem that popularly says: you only have to take into account what's underneath you -- the contributions from the part of the sphere with a greater distance to the center cancel.Gabriele Pinna said:What about the gravitational force acts by the Earth ?
The force that holds the center of the Earth together is called gravitational force. This force is created by the mass of the Earth pulling objects towards its center.
The force at the center of the Earth, also known as the center of gravity, is very strong. It is constantly pulling objects towards the center of the Earth with a force of about 9.8 meters per second squared.
No, gravitational force is the only force acting at the center of the Earth. However, there may be other forces acting on objects at the surface or within the Earth's layers due to various factors such as pressure and friction.
The force at the center of the Earth, along with other forces acting on the Earth, helps maintain the Earth's nearly spherical shape. Without this force, the Earth would not be able to hold its shape and would likely collapse in on itself.
The force at the center of the Earth remains relatively constant over time. However, slight fluctuations may occur due to changes in the Earth's mass distribution or external forces, such as the gravitational pull of the Moon and other celestial bodies.