Thread: Tell me about gravity.

This is really just a basic question.

Objects are supposed to fall at the same speed no matter what if there is no air resistance on a planet.

But the objects themselves have an attraction of their own don't they.

So is the attraction just so minuscule people don't bother mentioning it when they explain the theory of gravity in relevance to a vacuum?

I may have answered my own question hehe.

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MaA = -G Ma ME / RE

Mass cancels out hehe.

Gravity makes things go down.

If anything falls...blame gravity.

I didn't drop the statue of liberty! Gravity did!

To answer your question, there is a parallel between electric fields and gravitational fields. The force between two point masses (or spheres) is: G*m1*m2/r^2, where r is the distance between the points and G is the gravitational constant (see http://en.wikipedia.org/wiki/Gravitational_force ).

When they teach you in physics 101 that "g" is the constant acceleration with which objects fall, what they're not telling you is that the distance covered by an object falling a few feet is so small that "g" can basically be considered constant.

Also, just to be nitpicky:

Objects are supposed to fall at the same speed no matter what if there is no air resistance on a planet.

By speed, you really mean acceleration, of course?

MaA = -G Ma ME / RE

This equation is only valid when Ma is being treated as a point mass. The effect is negligible compared to the large mass.

The Newtonian equations are just good estimates of what we perceive as "gravitational force", when gravity is not really a force, but a bending of space-time. So the physics you learn in high school... not exactly 100% right - but close enough. You won't notice the errors in the equations (when compared to observation) until you reach astronomical scales.

Originally Posted by Replicon

By speed, you really mean acceleration, of course?

Yes I did mean acceleration. All though technically, acceleration is just the change in speed...so at any given moment they are also traveling the same speed =P


I came to the conclusion that when your comparing the two items against each other, the masses cancel out because there are two different masses. Thus the Earth falls towards the feather at a different speed, which could be found by switching the equation around so that the Earths mass is negated from the equation, and thus there would be the speed at which the earth is falling towards the feather, which is accurate, at any given point. In other words, it is only accurate for the specific moment and distance you are starting the equation, and there is probably another formula I haven't learned about that describes the average speed that exists during the whole distance traveled.

Phew that was a lot of talking lol. Lemme know if my conclusion is right anyone who reads it and knows X.X.

Originally Posted by CoLd BlooDed

Gravity makes things go down.

i concur wholeheartedly with this conclusion

Originally Posted by jacobo

i concur wholeheartedly with this conclusion

High tide is water being pulled upwards by the Sun's/Moon's gravity.

But that's being pulled towards them, which is basically down once you think about it.

The bigger the planet, the more gravity pushes down on things. If you are on a really small planet, there won't be much gravity.

Originally Posted by hankwheels

The bigger the planet, the more gravity pushes down on things. If you are on a really small planet, there won't be much gravity.

Depends on mass, not size.

Gravity is the bane to my existence...

whatever it is, it hurts if you don't use it right

Gravity is only a theory.

It should be noted that Intelligent Falling makes much more sense than gravity, and it is backed up by scripture. While physics still has problems explaining things on sub-atomic level, Intelligent Falling provides an elegant solution: It is only He who pushes things down to earth with the force of His almighty presence.



Here we see very clearly how God Almighty pushes water down some rocks:

Alternate theory:

Stuff gets lonely. Stuff seeks other stuff.

Simple. Elegant. Sexy.

More creepy than anything, I'd say.

No one really knows what gravity is actually...Its a mystery.

Scientits can tell you how it affects t hings and how it behaves...but what is the stuff made up of?

No one can really tell you.