The universal gravitational constant (G) relates the magnitude of the gravitational attractive force between two bodies to their masses and the distance between them. Its value is extremely difficult to measure experimentally.
What's Big G in physics?
The gravitational constant is familiarly known as "big G" to distinguish it from "little g," the acceleration due to the Earth's gravity.
How is 9.81 calculated?
In SI units, G has the value 6.67 × 10-11 Newtons kg-2 m2. The acceleration g=F/m1 due to gravity on the Earth can be calculated by substituting the mass and radii of the Earth into the above equation and hence g= 9.81 m s-2. ...
