what would be in the centre of earth? Which substance gives gravitational pull?
450478
We live on a very interesting planet. This planet actually hasn't completely cooled down yet and there is a lot of activity hundreds of miles below the Earth's crust (ther crust is where we are). The center of the Earth is very very very hot and a lot of substances (a lot of it being Iron (Fe) )are in molten form down there......Have you ever seen a volcano errupt (on a documentary or in a film?)? Well that stuff coming out is Molten Lava and is a mixture of substances (mostly rock) in liquid form. You cant get too close or you'll burn from the heat. I would go on telling you about this but then we'll be talking about another subject.\n\nThe gravitational pull of the Earth is because of its mass AND because of its rotation around the sun and itself. All bodies in the universe have a gravitational force and this force effects every other "body" in the universe (a bit like a draw in a tug-o-war) (This also explains why matter never can be completely annihilated and other aspects like the existence of dark matter and so forth....but that's advanced Astro-physics) \nThis gravitational pull is measured in NEWTONS (Newton is the guy that laid down the laws of gravity after an apple fell on his head.....) You'd weigh differently on each planet due to its MASS. For example if you where to lift a matchbox on Jupiter you would need a lot of help because it would weigh a lot more then it does here.....and so would you. So much so that your skeleton would not be able to support you and you would probably crumple into a meat heap......(i'm not going into detail because this will just go on and on to knew subjects.....you can find this info on the internet.....it's more fun to find out for yourself)\n\nI hope I've been helpful.......
180202
Neither. It's the mass of the planet itself. Everything that has mass projects a gravitational field. The more massive an object is, the bigger its gravitational "pull". This is why objects like the Sun can support several large planets, while Pluto (which has a moon about a third the size of it) gets pulled around by its moon.
1170472
You've got a couple of strange answers so far.  Look, the formula written above is correct, the mass of the earth is basically the same, but the mass of your surroundings isn't the same.  The pull of gravity is less the higher your elevation, greater the lower the altitude.  If you're on land with higher density, you'll have a greater pull then on land with a lower density.  Pretty much everywhere on land gravity isn't even, out in the middle of the ocean, it's very close to even.  But, keep in mind, these differences are pretty much negligible.  The only way to be able to measure the difference is with scientific equipment.  Actually, it's common practice to measure gravitational anomalies under ice sheets to gleam information about the formations underneath.
279317
gravity.\n\nany shape of mass that is not spherical is gravitationally unstable
897360
No, u will stuck in center. As it is familiar that the earth is more or less spherical in shape. So the "point of gravity" lies at the centre of the earth (the core we say).\n\nSo when u jump into that whole (which u digged) u will go inside, due to gravity. Once u reach the mid point (core), the gravity becomes zero. But with the old force, u will move further, making negative gravity, (that is gravity in opposite direction), from the opp direction, u will come back to the centre. \nThis will repeat until the gravity becomes zero, after that u will stuk up at the core.
693390
Gravity, centrifugal forces and centripetal forces
1130182
Um... I think maybe pull... if something is rotating/turning it is creating it's own little gravity field (I think!) therefore making it easier to pull.  I'm no scientist but this is an educated guess.
458068
Pressure is force over area and would be per m^2.  They use the center of the earth because the math works out such that all the mass of the earth could be treated as being at that point.  It doesn't have as much physical meaning as you might think.
239105
to use the gravitational pulls of the earth and the moon
710706
Gravity, friction and centrifigul.  Don't forget various applications of force = leverage, pulleys.
25445
The earth is APPROXIMATELY round due to gravitational forces.
179346
Besides the intense heat and pressure, gravity would be the major force acting on you (say if we lived in a world with no air resistance.) As you would get closer to the center of the earth you speed would be increasing, but once you start pulling away from the center you speed would be slowing down due to gravity pulling on you from the opposite direction. At the opposite side of the earth you find yourself to come to a standstill for a brief second until you get pulled back inward toward the center and emerge on the same side of the earth in which you started. You would be stuck in this cycle going from either side of the earth until someone threw you a rope and are able to pull yourself to the surface.
918251
Uh... it contains mass but doesn't have the act of the pull of the earth?
392530
it could be any of them...they have a center and the closer they are to the earth's surface the more gravitational pull they will have
314905
Imagine a molten ball of liquid rock in space. It will take the shape of a sphere due to the gravitational pull - any other shape would be turned into a sphere by gravity over time. \n\nNow, set this sphere rotating. Due to centrifugal forces, the sphere will bulge slighty round its equator. There you have it, the shape of the Earth.
66345
Yeah, gravity.  That's what slings everything around.  The enormous mass of the sun gives it an incredible gravitational pull.
1102975
Because gravity pulls equally in all directions.\nAs soon as the materials that the earth is made of began to gather together under self-gravity, the center pulled equally in all directions.  As heat from friction and radioactivity made much of the early earth molten, gravity pulled it into the most efficient shape -- a sphere.  Because of the earth's rotation and centrifugal force, it's not quite a perfect sphere -- it bulges a bit at the equator and is slightly flattened at the poles -- but it's simply gravity doing what it does naturally.  It's why all large bodies are in the shape of a sphere.