what is the self gravitational potential enrgy of earth?(challenging question for engineers and physicsts)?
464446
Gravitational potential = G *Mass of the earth/radius of the earth.\nIn other words its equal to Gravitational energy per unit mass.
1093952
The mass of the earth is 5983 Yg (yottagrams), and it gains another 40 Gg (gigagrams) every year from captured meteorites and cosmic dust.\nor\nThe mass of the planet Earth is 5.97 * 1024 kilograms.\n\nMost of the mass of the Earth is in the mantle, most of the rest in the core; the part we inhabit is a tiny fraction of the whole earth
888331
The previous suggestion of calculating the potential energy is good - I started doing it that way but realized this was easier:\n\nLet x be the distance along the tunnel from its center. The acceleration of gravity anywhere in the earth is gr/R pointing radially downward where r is the distance to the center, R is the earth radius and g the acceleration of gravity at the surface.\n\nTo get the component of this force along the tunnel it has to be multiplied by the cosine of the angle of the tunnel with the straight downward (radial) direction which is just x/r. In other words, the acceleration is just:\n\na = -gx/R\n\nThis has the same form as the force for a simple harmonic oscillator with spring constant k=g/R and unit mass and that is known to have period:\n\nT = 2pi/sqrt(k) = 2pi sqrt(R/g)\n\nThe trip from one endpoint to the other takes one half a period so this time is:\n\nt = pi sqrt(R/g)\n\nR is about 6400km and g = 9.8 m/sec so this seems to give about 42 minutes. Amazingly enough it seems to be the same for any straight line path connecting two points on the surface.
770211
each and every material is pulled towards the centre of the earth due to gravitational force.  since the object itself is placed at a depth equal to the radius of the earth, which means it is placed at the centre of the earth, it would not be pulled towards any point and hence the gravity at that point is zero.  when gravity is zero, naturally the weight is also zero.  but remember, there won't be any change in the mass of the body.
961066
Your right - gravity is ludicrously weak. The force of gravity of the entire earth on your body is held back by the electrostatic force of a single layer of atoms in your shoes. Gravity is weaker by many orders of magnitude than every other force in the universe.\n\nAnd its a good job it is. Because otherwise we would not exist. \n\nHowever, we have no theory as yet that explains the relative magnitude of forces. It is considered one of the failings of the theories of physics - the parameters that determine the magnitude of the forces simply have to be fed into the equations from observation.
778096
The height of the ramp give potential enery in the following format\n\nE = mgh      where E is potential energy, m is the mass of the car in Kgs, g is the gravitational acceleration of the planet you're on (in meters per second per second (9.8 on earth)) and h is the height of the ramp.\n\nThe angle or slope of the ramp will not affect the potential energy, but will have an effect on the rate of change of potential energy.
748344
Every particle has a gravitational force associated with itself. It the basic nature of the particle.\nThe force is given by : F = G(m1*m2)/r^2\nwhere G= Universal constant of Gravity.\nSince the earth is very huge, the force between 2 humans is negligible as compared to the each of them to earth
362695
The solar constant for Earth is sc = 1360 W / m2 = 1.36 GW / km2 [1]. Assuming that the radius of the Earth is RE = 6,366 km then the total rate of energy flow (power) on Earth is equal to: \n\n\nPE = sc    RE2  1.7  108 GW (1) \n\nSome of this energy accumulates in the Biosphere, but most of it is radiated back to space in the form of electromagnetic radiation. \n\nThe temperature of the Sun's surface is TS  5800 K. Assuming that the Sun is a black body at temperature TS = 5800 K and that all of the energy impinging on Earth from Sun is radiated back into space in the form of black body radiation it can be shown that the Earth black body temperature TE is [1] : \n\n\nTE = (0.25) 1 / 4  (RS / RSE) 1 / 2  TS  280 K (or  7oC) (2) \n\nwhere: RS  7  108 m - radius of the Sun, RSE  1.5  1011 m - average Sun-Earth distance \n\nThe Sun is the major energy source for Earth. Geothermal energy is comparatively minor, since ice caps formed on the Earth's Poles where the average intensity of the Sun's radiation is low.
905049
First assume that we neglecting any losses from air resistance or internal friction.\n\nWith that simplification, imagine two states:\n1) you are on the bridge 100m above the water and at rest\n2) you are suspended by the spring at its point of maximum extension, and therefore with zero velocity\n\nSince we assumed that there were no losses, the energy of both of these states is equal. Where is that energy located?\n -->1: your gravitational potential energy (no kinetic energy, no stored elastic energy)\n--> 2: your remaining gravitational potential energy, and the stored elastic energy in the spring (by definition, no kinetic energy)\n\nSo what has happened is that the spring has stored elastic potential energy that is equal to your loss of gravitiational potential energy. That's the only way the energies of the two states are the same.\n\nNow you can set up some equations. Let's say that you start at height H0 and end up at height H1.\n\nchange in PEg= m * g * (H1-H0)\nchange in PEk = 1/2 * k * [(H1-H0)-30m]^2\nwhere we have accounted for the 30m long unstretched length of the spring.\n\nNow by observing that -PEg = PEk, and plugging in the given values for m and k and the known value for g, you can readily solve for the change in height (H1-H0) (it should be < 0) It's a quadratic, so you expect to find one answer that is not physically realizable - reject that one, and select the other one.\n\nDoes that help?
312434
The Gravity Economy\n\nGravity as a power source is fascinating. It is more abundant than hydrogen, more far reaching than solar power. It exists in dark places with still winds and in climates cold and warm. We've been tapping its power for thousands of years -- through water wheels, dams, and clockwork counter weights.\n\nGeothermal power is a form of gravity power at work. The pressure of the outer earth on its core keeps things hot, rocks and metals, molten. Temperatures can reach 9,000 degrees, almost as hot as the Sun. The original heat may date back to the formation of the earth, which was also the result of gravitational forces. Geothermal power is being used cleanly and successfully in areas where the heat of the earth is relatively easy to tap.\n\nHowever, most of gravity's power comes from devices that use the flow of water. Precipitation conveniently drops water for us in high places in the form of snow and rain, then gravity does the work of transporting it downhill to the sea. Dams and waterwheels are the best known examples. These systems work great and produce no emissions. In fact, by acting on the water of the Columbia River, gravity is powering my computer right now.
61784
That's an interesting qts. I assume that you wish to invlove pure physics in this qts. Forget all the heat at the core of the earth and also air resistance.\nConsider pure gravitation theory.\n\nIf say the fellow who fell in the hole has mass m\n\nThen force of gravity exerted by the earth is :\n\n  F = GMm/(r*r) ..... Where G - universal gravitation constant\n\n                            M - Mass of the earth\n                            r - distance between earth and body of mass m\n\n          acceleration due to gravity\n            = (1-h/R)g   .... where h is distance of body beneath the earth's surface and g is acceleration due to gravity at the surface of the earth.\n\nSo as the body comes closer to the core of the earth, h tends to R.\nSo the acceleration of the body goes on decreasing very much. So, body may not actually hover, since his velocity will be constant the instant it is at the core.
408862
the force between the object and the earth is dependant on mass, but the acceleration of the object towards the earth is 9.81 meters&#92;second. (ignoring air resistance)\n\nforce = mass x acceleration
48083
If the mass of the earth changes, then if we could "weigh" it on a scale, its weight would change. Changing the mass of the earth definitely affects its rotation rate, and its orbit, as well as all the other orbits of bodies in the solar system, including the sun, and of course, bodies outside the solar system. \n\nAll of the laws of motion and gravity that the earth and the other bodies obey depend on the mass of the earth.\n\nHow might mass of the earth change?\n \n1. The earth is gaining mass every year from meteorites of course. The amount of material falling to earth is estimated to be between 37,000 and 78,000 tons per year (see first reference).\n\nI am not sure if this includes material from the solar wind, or from the tails of comets, or from cosmic dust (see below) which are also sources of material from space that the earth gathers, but I believe it does. \n\n\n2. The earth is also losing material because we are now launching satellites and sending space vehicles off on missions. \n\n3. At the boundary of the atmosphere and space (the exosphere) where air can escape into space. The amount of air that is lost depends on how fast the ions, atoms and molecules in the upper atmosphere are moving. I have including a web page that discusses this below. \n\n4. When radioactive material decays, it can emit electromagnetic radiation (gamma rays) that carry off a tiny amount of mass. Some of these gamma rays might make it all the way out of earth's atmosphere, but very few I would imagine. I am not sure how to estimate this. It would definitely have to be balanced against the flood of radiation that the earth is being bathed in by the sun and by cosmic rays. \n\nWithout doing any calculations, I would guess that the earth is probably experiencing a net gain of mass every year, and this increases the force of gravity between it and all the other celestial bodies. It also will make it spin more slowly, as the moment of inertia of the earth changes. However, the gain is very small. From the figures above, the earth's mass increases by roughly 10^(-15) per cent per year; that is, the earth experiences a gain of about 0.000000000000001 %  per year.
830124
Nothin would happen.\nIf you consider two bodies the earth (name it E) and a large mass (m). \ninitially M rests on E. and you lift mass M. the force used to lift it will also act on E.\nAlso if you consider the mass M and E. as a system force exerted on dropping M would be internal and since internal forces do not cause acc. the Earth will not get unbalanced.\n\nThats good for us isn't it...
12482
weight of earth is 5.9736×1024 kg\n\nOther info about earth:\nAspect Ratio 0.996 647 139 \nEllipticity 0.003 352 861 \n  \nRadius: \nEquatorial 6,378.135 km \nPolar 6,356.750 km \nMean 6,372.795 km \n  \nDiameter: \nEquatorial 12,756.270 km \nPolar 12,713.500 km \nMean 12,745.591 km \n  \nCircumference: \nEquatorial 40,075.004 km \nPolar 39,940.638 km \nMean 40,041.455 km \n    \nSurface Area 510,065,284.702 km² \n Land 148,939,063.133 km² (29.2 %) \n Water 361,126,221.569 km² (70.8 %) \n  \nVolume 1.0832×1012 km³ \nMass 5.9736×1024 kg \nDensity 5,515 kg/m³ \nEquatorial surface gravity 9.780 m/s²\n(0.997 32 g) \nEscape velocity 11.186 km/s \nSidereal rotation period 0.997 258 d (23.934 h) \nRotational velocity\n(at the equator) 465.11 m/s \nAxial tilt 23.439 281° \nRight ascension\nof North pole 0° (0 h 0 min 0 s) \nDeclination 90° \nAlbedo 0.367 \nSurface temperature\n- min\n- mean\n- max \n185 K\n287 K\n331 K \nSurface pressure 100 kPa \nAdjective Earthling or Terrestrial
497338
Gravitational Potential Energy does. However, there are other types of potentialenergy. For example, a battery has potential electrical energy and that is not dependent upon gravity. The food we eat has potential energy that is not utilized until we need it. Atoms have potential nuclear energy. If you are studying Mechanical Energy....motion, speed and the like then probably you ARE talking only about Gravitational but usually it is labeled as such...GPE.
406724
I think you are interested in the earth's mass.  If you wanted to earth's weight ( with respect to the sun) you would need the earth's mass and the sun's gravitation pull.\n\nIt doesn't really make sense to find the earth's weight relative to the earth's gravitation pull.