acceleration of gravity
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acceleration of gravitySymbol: g . The acceleration to the center of a planet (or other massive body such as a natural satellite) of an object falling freely without air resistance, i.e. acceleration due to downward motion in a gravitational field. It is equal to GM /R 2, where G is the gravitational constant and M and R are the mass and radius of the planet. The acceleration is thus independent of the mass of the accelerated object, i.e. it is the same for all bodies (neglecting air resistance) falling at the same point on the surface of the planet, satellite, etc.
On Earth the value of the acceleration of gravity is about 9.81 meters per second per second. The value varies from place to place on the Earth's surface because of different distances to the Earth's center and greater acceleration toward the equator. In addition, it is affected by local deposits of light or heavy materials. See also microgravity; weight; weightlessness.
Acceleration of Gravity
(or acceleration of free fall), the acceleration imparted to a free material particle by the force of gravity. Such acceleration would be undergone by the center of gravity of any body if the body were to fall to earth in a vacuum from a small altitude. Like the force of gravity, the acceleration of gravity depends on the latitude φ and the elevation H above sea level. The acceleration of gravity g is approximately 978.049(1 + 0.005288 sin2 φ – 0.000006 sin2 2φ) – 0.0003086H. At the latitude of Moscow at sea level g = 981.56 cm/sec2.