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2006-12-07 05:31:43 · 25 answers · asked by egidijus m 1 in Science & Mathematics Physics

25 answers

Gravity is caused by mass. It has nothing to do with spinning. Every object exerts a gravitational force on every other object in the universe. This force is directly related to the mass of the objects, and inversely related to the square of distance; in other words, if you double the distance, the force drops to 1/4 its initial pull.

Centrifugal force, which is caused by spinning, is entirely different. Centrifugal force is an illusion caused by the force exerted on a spinning object in order to prevent it from flying in a straight line tangent to its circle of motion. In reality, there is only one force acting upon the object, pulling it towards the centre of its circle of motion. The illusion of centrifugal force is caused by the momentum of the already-moving object. Centrifugal force OPPOSES gravity; without gravity, you would be thrown from the surface of the earth at a direction tangent to its surface. Centrifugal force is the reason why amusement park rides seat the rider on the inside of the loop instead of the outside; if the rider was on the outside, they could be thrown from the car.

2006-12-07 05:50:29 · answer #1 · answered by computerguy103 6 · 5 0

As far as im aware there is no known reason for why gravity exists, its like asking why are we here...we just are...
Gravity is simply one of the main forces which make every thing possible along with the strong nuclear force, the weak nuclear force and the electromagnetic force.
Although what is known is that all mass is affected by gravity. Every bit of mass has a grvitational pull towards another bit of mass. The size of this gravitational pull however is relient on the mass of this mass and distance from each other.
little else is known about gravity though, or so i have been told...

2006-12-08 18:57:04 · answer #2 · answered by Anonymous · 0 0

The force of gravity performs work. For this reason it must have an energy source. The equation describing this is part of the physics trilogy - E = mc2, m = E/c2, and c2 = E/m. The last is that for a gravitational field, or a field of physical time.

Notice that hydroelectric power is the result of gravitational energy. Water is the object used, but the force causing the water to flow downward as it does is that of gravity. Were it not for this force, water would float into outer space.

That which forms a gravitational field in our planet is the heat energy contained within it. Were there to be no heat energy within our planet, then our planet would have no gravitational field. This concept is true, no matter how large the mass. You might check out the following sources for further reasons.

http://360.yahoo.com/noddarc
http://timebones.blogspot.com

2006-12-08 15:06:38 · answer #3 · answered by Anonymous · 0 0

After wading through most of the stupid answers you've gotten so far, here's the straight poop --

Einstein theorized that the presence of any mass, no matter how large or small, distorts spacetime. Imagine a thin rubber sheet with a bowling ball sitting on it. Under the ball there's an indentation. If a marble is placed on the rim of the dimple, it rolls down the slope. Substitute the rubber sheet for spacetime and the bowling ball for mass and you've got the basic idea.

This isn't just theory either--it's been proven over and over again that what we cal gravity is truly a warping or bending of spacetime caused by mass. Just how mass does this is NOT known, but rotation, orbits, nor any other kind of movement have anything to do with it.

2006-12-07 14:18:03 · answer #4 · answered by Chug-a-Lug 7 · 3 0

I think gravity is caused by mass. Between any 2 objects having mass, there exists the force of gravity. Gravity has a direct proportion with mass. The larger the mass of and object, the larger the gravitational pull. We do not notice gravity between 2 objects for example placed on a table because of their very small masses. THe earth's gravity is very significant therefore because of its mass

2006-12-08 13:46:45 · answer #5 · answered by b_prince 3 · 0 0

Gravity is an attractive force between any pair of masses. Its magnitude is easily calculated using Newton's formula, F = -GMm/r^2. Einstein's General Relativity offers a different way of visualizing and calculating it, considering space-time as warped in the presence of mass. In particle physics, the force is mediated by the exchange of virtual particles called gravitons.

That tells you about gravity, but it doesn't answer your question. The only honest answer is that we don't know. Neither do we know why it is inverse square with distance, or why it is unaffected by anything else and cannot be insulated or shielded, or why it is always attractive. The only satisfying answer is, that's how God created the universe and its physical laws.

2006-12-07 14:28:34 · answer #6 · answered by Frank N 7 · 1 0

The mass of the objects result in gravity.
The acceleration due to gravity is based on the formula, GM/r^2, where G is the Gravitation constant, M is the mass of the larger object (e.g. Earth or the Moon) and r is the distance from the middle of this object to the middle of the smaller object.

2006-12-07 23:08:40 · answer #7 · answered by Kemmy 6 · 1 0

Man! There are some seriously off-the-mark answers here!
I'm utterly astounded.

The short answer:
Gravity is caused by mass.
It is an attracting force acting between masses.

Anything posessing mass is attracted to all other things posessing mass. You, me, the cat, the sun, the earth, the moon, the oceans, ants, lobsters, cakes, teapots, they are all attracted to each other. (this is not an exhaustive list by the way).

The mangitude of the attracting force between two masses is proportional to the product of the two masses (so large masses have a greater attractive force between them) and inversely proportional to the square of the distance between their centres of mass, (so objects which are further apart have less force between them)

For example: I am quite close to the earth, I'm also quite close to my cat. However, the earth has a little bit more mass than my cat, so there's more force between me and the earth than between me and my cat.

For a more accurate description of the mechanism of gravity and how it can affect light and time, see above.
Nice one "braxton_paul"

Cheers.

2006-12-07 14:24:38 · answer #8 · answered by chopchubes 4 · 1 0

Apparently in the absence of all matter, space possesses a kind of 'mass field' with its own associated particle- the so called Higgs Boson.(particles mediate other fields too- electromagnetic force:the photon, nuclear force:the meson etc) When material particles move through the Higgs field, they cause fluctuations, the Higgs Bosons, which adhere to these particles and create the property of 'inertia' The H-particle is extremely massive- about 100+ proton masses in its ground state. It will be necessary to wait 'till next year before experiments at CERN involving proton/antiproton collisions at the required energies (prob at least 200Gev) reveal the particles existence/or not!

2006-12-07 22:43:02 · answer #9 · answered by troothskr 4 · 0 1

All objects with mass have gravity. (It's got nothing to do with rotation or movement!)

2006-12-07 13:34:32 · answer #10 · answered by Anonymous · 9 0

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