Question

relationship between centroid and centre of gravity

Answer 1

centroid is also called the center of mass. Center of mass of any geometrical figure is a point where whole mass of the body concentrates. Therefore, centroid of a triangle is the point at which its overall mass is focused. If we want to balance a triangular plate on the tip of a sharp object we shall be able to do it very easily if we put the tip over the centroid of the triangle. 

The Centroid of a triangle is the point where the three medians of the triangle meet (We know that the line segment meeting the vertex and midpoint of opposite side is called its median). Centroid is also known as center of triangle. Following figure given below demonstrates centroid of a triangle;  point P is the centroid of △ABC.




The centroid of the triangle divides the medians of a triangle in the ratio of 2 : 1 from the vertex as shown in the following




Thus, AG : GD = 2 : 1  AG/GD  =2/1

The Center of Gravity is the average location of the weight of an object, the geometric property of any object.  For every object the weight always acts through the center of gravity.  A body whose Center of Gravity is above its base of support will be stable only as long as the vertical line downward from the Center of Gravity falls within the base of support.




The Critical Point is reached when the Center of Gravity is no longer above the base of support
hope that helps