As the figure above shows, the center of gravity of a body is the point where the application of the force of gravity can be considered. If the dimensions of the body are small compared to the size of the Earth, it is possible to demonstrate that the center of gravity practically coincides with the center of mass.
In order to obtain, through an experiment, the center of gravity of a plate-shaped body, that is, constant thickness, we can proceed as in the figure below. Initially we suspend the body by a point s1 any and let it reach the equilibrium position (a), defining the vertical line r.
Then we suspend the body from another point, s2, and again we let it reach the equilibrium position (b), defining the vertical line s. The center of gravity (c) will be at the intersection of the straight lines r and s.
A toy that we can easily find is sketched in the figure below. A doll is supported by an S support. A rigid wire passes through the doll, the ends of which are fixed in two balls with a mass larger than the doll's. Thus, the center of gravity (G) of the set is
bellow of support S and the system is in stable equilibrium. When we move the toy very slightly away from its balanced position, and then release it, it tends to return to its starting position.
By Domitiano Marques
Graduated in Physics
Brazil School Team
mechanics - Physics - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/fisica/centro-gravidade-cg.htm