Equilibrium

Equilibrium

If the resultant of all the force acting on a body is zero then the body is said to be in equilibrium.
If a body is in equilibrium, it will be either at rest or in uniform motion. If it is at rest, the equilibrium is called static, otherwise dynamic.

Static equilibrium is of the following three types :

1. Stable Equilibrium

If on slight displacement from equilibrium position, a body has tendency to regain its original position, it is said to be in stable equilibrium.

2. Unstable equilibrium

If on slight displacement from equilibrium position, a body moves in the direction of displacement and does not regain its original position, the equilibrium is said to unstable equilibrium. In this equilibrium, the centre of gravity of the body is at the highest position.

3. Neutral Equilibrium

It on slight displacement from equilibrium position a body has no tendency to come back to its original position or to move in the direction of displacement it is said to be in neutral equilibrium. In neutral equilibrium, the centre of gravity always remains at the same height.

Conditions for stable Equilibrium

For stable equilibrium of a body, the fallowing two conditions should be fulfilled.
1. The centre of gravity of the body should be at the minimum height.
2. The vertical line passing through the centre of gravity’ of the body should pass through the base of the body.