What do you mean by centroid? What is the difference between center of gravity and centroid?
Centroid:
Centroid: It is the geometrical center of any object of figure. It is the weighted average of area of any figure. Actually it referring to a central point that represents the “average” or “balance point” of a shape, object.
For regular bodies like circle, triangle, rectangle we can easily find its geometrical center.
- For Rectangle centroid is the point located at the intersection of its diagonals, which is the midpoint of both the length and width of the rectangle.
- For circle it is the center point of the circle.
- For triangle it is the point of intersection of its three medians (lines connecting a vertex to the midpoint of the opposite side).
Centroid of irregular body:
For irregular shaped objects it is the weighted average of its area.
Let’s assume an irregular shaped figure or object having an area A . The body can be considered as a summation of n numbers of small areas a1,a2,a3,a4……an represented by the points C,D,E,F,H,I,J …….
Now assume the geometrical mean or geometrical centre of the figure is point G is at a distance \(\overline{X}\) from the reference plane or axis.
\(\overline{X}\)= \(\frac{a_{1} x_{1}+a_{2} x_{2}+a_{3} x_{3}+ . . . . a_{n} x_{n} }{ a_{1}+a_{2}+a_{3}+. . . a_{n} }\)
where \(\overline{X}\) is the distance of centroid from the reference axis.
Center of gravity:
Center of Gravity (CG) is the point where the total weight of the body considered to act (the point at which the body balances under gravity). It is the average position of the weight distribution.
It may be regarded as the point about which the total torque due to gravity is zero.
It means you you support a body at this point the bosy is in stable equilibrium.There is no moment due to the weight.
Key difference between centroid and center of gravity:
Centroid is the geometrical center where as center of gravity is the point where total weight is considered to act. So centroid is related to area where as center of gravity is related to weight of gravity.
Centroid is applicable for any planes of geometrical shapes or figures or lamina where as center of gravity is applicable to any bodies with weight.