Why does the force of gravity change at various places on earth?

Answer 1

Because gravitational force is a function of both the masses of the objects, and the distance between the objects that are attracting one another.

If you move to a different spot on earth, Your mass and the earth's mass doesn't change, but the distance between the center of your body and the center of the Earth could change.

So the closer you are to the center of the earth, the greater the gravity. The further away you move from the center of the earth, the weaker the gravity.

So if you are in Death Valley, you would weight slightly more than you would if you were at the top of Mount Whitney.

Answer 2

Two things determine gravitational pull.

First, mass. The heavier an object is, the stronger the gravity. At a given distance, a planet (or any other object) with twice the mass has twice the gravity.

Second, distance from the center (of mass) of that object.

Gravity decreases with the square of the distance. If you are 2 times further from the center of the object, gravity pull is 1 / (2x2), or 1/4 as strong.

To illustrate this concept further, if you were 10 times further from the center of the object, gravity would be 1 / (10x10), or 1/100th as strong.

Distance to CENTER is very important. If you climb up a mountain, you WILL be lighter than you were at the bottom (provided you drank exactly as much water as you sweat and you didn't eat), but the difference is so small that you'd have to have a VERY accurate scale to tell the difference.

Back to planets. Earth is dense, and relatively small. High gravity for its size. The moon is very small, and less dense. It has 1/81st of Earth's mass, but since you are 3.64 times closer to the center, that offsets the difference in gravity, so the moon's gravity is about (1/81)/((1/3.64)x(1/3.64)), or (1/81)/(1/13.25), or about 1/6th of Earth's gravity.

Saturn is gigantic. It weighs as much as 75 Earths, but Saturn has about 9x the Earth's diameter (which puts you about 9x further from the center). The density of Saturn is so low that gravity at the top of the clouds is even less than it is on Earth. But, there's nothing solid to stand on up there - just like being on top of the clouds on Earth.

And finally, Jupiter is monstrous. It weighs as much as 318 Earths, and is 11x as far across. Gravity at the top of Jupiter's clouds = 318/(11x11) = 2.63 Times as strong as Earth's.

Answer 3

The farther you are from the center of a mass the less affect it has on you. The Earth, for example, is far away from stars of greater mass than the sun, but their gravitational force on the Earth is insignificant. It works the same as you get further away from the center of the Earth. The Earth is slightly bugled out at the equator because of its centripetal force, making it further from the center of the Earth. This makes you a pound lighter at the equator than at the North Pole, which would be closer to the center of the Earth.

Answer 4

The g(small g value) value on the earth is inversioly proportional to square of the radius .the radius of the earth varies from place to place hence it varies