View source for Gravitational constant

'''G''' is the universal gravitational constant:<ref>http://physics.nist.gov/cgi-bin/cuu/Value?bg</ref>

:<math> G = 6.67408(31) \times 10^{-11} \ \mbox{N} \ \mbox{m}^2 \ \mbox{kg}^{-2} \ </math>

It is used in {{hs|Isaac|Newton}}'s formula for the gravitational force between two objects, which is: 

:<math> F = G \frac{m_1 m_2}{r^2} </math>

where 

:<math> {F} \ </math> is the force between the two objects
:<math> {m_1},{m_2} \ </math> are the masses of each object
:<math> {r} \ </math> is the distance between the two objects.

==Acceleration due to Gravity==
The lower case <math>g</math> is known as the acceleration due to gravity. It is the [[acceleration]] of a body experiences due to [[Earth]]'s gravitational field at the [[Earth]]'s surface. It varies slightly across the surface of the earth due to differences in [[altitude]] and local geology. The rotation of the earth also affects it, causing the earth to bulge around the [[equator]], increasing the distance between the surface and the centre of the earth. It has a value of approximately <math> g = 9.81 \ \mbox{m} \ \mbox{s}^{-2}</math>.

==References==
{{Reflist}}

[[Category:Physics]]