Acceleration due to gravity

surface of a massive body, such as a planet. Also known as the acceleration of free fall, its value can be calculated from the formula

g = GM / (R + h) 2

whereM is the mass of the gravitating body (such as the Earth), R is the radius of the body, h is the height above the surface, and G is the gravitational constant (= 6.6742 × 10-11 N·m2/kg2). If the falling object is at, or very nearly at, the surface of the gravitating body, then the above equation reduces to

g = GM / R 2

In the case of the Earth, g comes out to be approximately 9.8 m/s2(32 ft/s2), though the exact value depends on location because of two main factors: the Earth's rotation and the Earth's equatorial bulge.

The earth is not perfectly round, it is slightly egg-shaped, wider at the equator as it spins. The farther you are from the center of the earth the less gravity, the less you weigh. So if you are on a high mountain or at the equator you will weigh a teeny bit less. Your mass stays the same thought

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