# centre of gravity

Centre of gravity is the point of application of the resultant force due to the earth’s attraction on it. All bodies are made of a large number of tiny equal particles each of mass “m” and pulled towards the earth with a force “mg”. If the total mass of the entire particle in a body is “m” then the resultant force of gravity on the body is mg and it acts vertically downwards at the point G.

The centre of gravity or centre of the mass is a fixed point in the object where the resultant weight, (force of gravity) seems to act. If the centre of gravity is taken to, any other point of support is not zero.

Centre of gravity or regularly shaped object.
The mass or weight is evenly distributed and its centre or gravity is in the middle, which is at the geometric centre of the shape.

Finding the centre of gravity of an irregularly shaped object (lamina).

Marking holes: Three holes “A”, “B” and “C” are made in the object at the edges far away from each other.

Marking the cross lines: The object is suspended on a retort stand from each of the holes and plumb (or pendulum bob) is used to trace the centre of gravity by marking a line on the object tracing the plumb line thread when swinging stops.

Repeating: The experiment is repeated with the object hung at B and C and cross lines marked. The point C.O.G at which all the lines cross is the centre of gravity of the body.