# Weight and Universal Gravitation

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#### DemocAnarchis

##### Weight and Universal Gravitation
« on: February 13, 2007, 11:59:45 AM »
The law of Universal Gravitation states that "every single point mass attracts every other point mass by a force heading along the line combining the two. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses"

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`F=G*{(m1*m2)/r^2}`

Where F = Gravitational Force, G = Universal Gravitational Constant, m1= Mass object 1, m2= Mass object 2, and r = separation between objects.

This has been demonstrated to be correct experimentally, and has been replicated using two dense spheres, so please do not waste time arguing that the experiments were faked, or that the scientists were bribed. It has been verified. That is not a point of contention.

Now, this can be applied to an object on the surface of the earth, exerting and being the subject of a force.

Applying Universal Gravitation to this requires a slight altering of form:

Weight (F) = G*{(M*m)/r^2}

Now, using the accepted model of a Spherical Earth, and using a sphere of 1 kg in mass for simplicity, to determine its weight:

G=6.67300 × 10-11 m3 kg-1 s-2
M(Mass of earth)=5.9742 × 10^24 kg
m(Mass of object)=1kg
R(Distance from object to centre of earth/radius of earth) - Note, assuming radius of object to be negligible. Within margin of error for measurement of earths radius anyway. = 6 378100 m

Weight = 9.7998kg·m/s²

This is what is to be expected, as weight = mass * gravity.

Now, I hope none of you are going to argue the toss here either.

When we try to apply this valid model to the Flat Earth, we are presented with a massive problem. You have two options; to decide to deny gravity and go along with your model of the earth accelerating "up"  at 9.8m/s, or to accept gravity exists. Either way your model is invalidated.

Option 1 - Accept Gravity:

As I have demonstrated, gravity is affected by the distances between objects. More precisely, their centres of mass. Your model would have objects at the edges of the earth and objects over the centre of mass weighing ridiculously different. Not the case.

Option 2 - Deny Gravity, and go along with Up at 9.8m/s.

Problem. Big one. Gravity can be demonstrated, has been demonstrated, reproducibly and independantly at different height above sea level. And guess what? Just as Newtons model predicts, the value for gravity changes. The value for at sea level is 9.8m/s, the value at the peak of everest is .2m/s less. Your model does not explain this. It has been demonstrated thousands and thousands of times that gravity is proportional to distance from the earth's centre.

I dont see any logical fallicies in my post, I'm sure you will be quick to point the out if I have. And bullshit explanation from Tom Bishop aside, I dont think you can explain this with your Flat Earth model. Q.E.Fuckin.D.

Edit-corrected units, not that it matters

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#### Tom Bishop

##### Weight and Universal Gravitation
« Reply #1 on: February 13, 2007, 12:12:56 PM »
Being in a gravitational field is equivalent to being in an accelerating reference frame. Acceleration warps space time. It is the mechanism for the "gravitation" you know and love.

See: General Relativity, Special Relativity, and the Equivalence Principle.

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#### il0vepez

##### Weight and Universal Gravitation
« Reply #2 on: February 13, 2007, 12:15:08 PM »
Not to be a dick, but your units for weight are incorrect.

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#### DemocAnarchis

##### Weight and Universal Gravitation
« Reply #3 on: February 13, 2007, 12:17:35 PM »
I though so, units have never been a strong suit of mine, but I think my calculations are still correct enough to make a comparison?

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#### il0vepez

##### Weight and Universal Gravitation
« Reply #4 on: February 13, 2007, 12:17:55 PM »
Quote from: "Tom Bishop"
Being in a gravitational field is equivalent to being in an accelerating reference frame. Acceleration warps space time. It is the mechanism for the "gravitation" you know and love.

The force of gravity is greater near sea level than at higher elevations, as predicted by Newton's Law of Universal Gravitation.  You failed to acknowledge this, and your model fails to explain this observation.

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#### il0vepez

##### Weight and Universal Gravitation
« Reply #5 on: February 13, 2007, 12:20:30 PM »
Quote from: "DemocAnarchis"
I though so, units have never been a strong suit of mine, but I think my calculations are still correct enough to make a comparison?

The Newton, N=kg*m/s^2, is the guy you're looking for.

Sorry, the first thing I do when I see physics is check the units.  I just thought I'd point it out nicely before someone did it rudely.

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#### Tom Bishop

##### Weight and Universal Gravitation
« Reply #6 on: February 13, 2007, 12:26:19 PM »
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The force of gravity is greater near sea level than at higher elevations, as predicted by Newton's Law of Universal Gravitation.

The gravitation due to acceleration is also greater near sea level than at higher elevations.

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You failed to acknowledge this.

You failed to understand.

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#### manta_ray007

• 95
##### Weight and Universal Gravitation
« Reply #7 on: February 13, 2007, 12:31:26 PM »
Quote from: "Tom Bishop"
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The force of gravity is greater near sea level than at higher elevations, as predicted by Newton's Law of Universal Gravitation.

The gravitation due to acceleration is also greater near sea level than at higher elevations.

Wouldn't that imply that the Earth's higher regions are accelerating more slowly than the sea-level areas?

That makes no sense...  The mountains should be going more slowly than the Earth, and thus have fallen off or been crushed down into flatlands where they could continue accelerating normally.

Ow...  My head...  Laws of physics being violated....  Not fun...

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#### Tom Bishop

##### Weight and Universal Gravitation
« Reply #8 on: February 13, 2007, 12:35:53 PM »
Quote
Wouldn't that imply that the Earth's higher regions are accelerating more slowly than the sea-level areas?

That makes no sense...  The mountains should be going more slowly than the Earth, and thus have fallen off or been crushed down into flatlands where they could continue accelerating normally.

Ow...  My head...  Laws of physics being violated....  Not fun...

Nope. There are two different forces at play here. The direct force you feel due to ascension, and the indirect force you feel due to gravitation.

The direct force due to ascension is the more noticeable of the two.

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#### il0vepez

##### Weight and Universal Gravitation
« Reply #9 on: February 13, 2007, 12:58:43 PM »
So lets see your model.  You know, those things written in a language we call math.

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#### Tom Bishop

##### Weight and Universal Gravitation
« Reply #10 on: February 13, 2007, 01:40:50 PM »
Quote from: "il0vepez"
So lets see your model.  You know, those things written in a language we call math.

Einstein has already established the mathematical basis for the Equivalence Principal.