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Old 10th Nov 2005, 07:51
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Red Line Entry
 
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The universal constant of gravitation (G) is a variable frequently used in fields like orbital mechanics.

The value of G is a constant that does not change no matter where one is in the universe. The value of g, however, does vary for each planet, star, moon, or other large body. These two gravitational parameters are related by the equation:


g = GM/r2 (where r2 means r squared)

and

g = acceleration due to gravity (m/s2)
G = universal gravitational constant (m3/kg/s2)
M = mass of the body (kg)
r = radius of the body (m)

Now,

G = 6.673 x 10-11 m3/kg/s2
Mass of Earth = 5.98 x 1024 kg
Radius of Earth = 6.375 x 106 m

Plug into equation above gives:

g = 9.81 m/s2


So the difference between g and G is a factor of one hundred and fifty billion! Call me picky but I think that is enough to count!

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Or are we going round in circles here?
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