Centre of Gravity - Elementary Science

Every body is made up of a large number of particles.

In a rigid body the particles are held together in a fixed position relevant to one another.

Each particle is attracted towards the center of the earth with a force equal to its weight.

Let F1, F2, F3, F4, F5, F6 be the forces acting on the particle P, Q, R, S, T, U respectively.

The resultant of all these forces is equal to the vector sum given by F=F1+F2+F3+F4+F5+F6.

The line showing the direction of this resultant force is called the line of action.

This total force or weight of the body appears to act through the fixed point G irrespective of the position or orientation of the body, this point G is called center of gravity of the body (G) the position of the centre of gravity of a body may be falling inside or outside the material of the body. 

Center of gravity of a body is defined as a point of application of the resultant force due to the earth`s attraction on it. Center of gravity of regular bodies.

Let us consider some regular bodies. Take uniform meter scale A, B and note its mid point G. if the scale is suspended at point P or Q it dose not remain . if the scale is suspended at the mid point G its remain horizontal and stable. This geometric mid point is the center of gravity G of the scale.

For a body which has uniform density and regular shape the center of gravity G coincides with the geometric center.