The center of gravity
of an object is a theoretical point
which identifies its effective location. It is roughly the three-dimensional average of the positions of all protons and neutrons
in the object.
An easier way to identify
the location of the center of gravity is by suspending
a non-central part of the object in place, while allowing it to spin sufficiently on any axis
. Once it comes to rest
, the center of gravity lies along the line containing the suspended point and with the direction of the gravitational force vector
. By performing this process from two or more points of suspension, the center of gravity can be isolated as a point.
In many physical calculations
, the center of gravity can be used to represent the position
of the entire object, so long as the object's spin, etc. are not concerned.
If the object has a simple geometric shape
, with its mass evenly distributed (unweighted dice, a baseball), the center of gravity will lie at the geometric center
of the object.