Adhesive and cohesive force

Adhesive and cohesive force

Adhesive and cohesive force defined as:

Adhesive force

It is the force of attraction acting between molecules of two different materials. For example, the force acting between the molecules of water and glass.

Cohesive force

1) It is the force of attraction acting between molecules of the same material. For example, the force acting between the molecules of water or mercury etc.
2) If cohesive force is large then the adhesive force, the liquid will not stick to the vessel containing it. It is so in case of mercury and glass.
3) If cohesive force is less than the adhesive force, the liquid will stick to vessel containing it. It is so in case of water and glass. Cohesive or adhesive force varies inversely as the eighth power of distance between the molecules.

Buoyant force or Buoyancy

1) It is an upward force acting on the body immersed in a liquid.
2) It is equal to the weight of liquid displaced by the immersed part of the body.
3) The Buoyant force acts at the centre of Buoyancy which is the centre of gravity of the liquid.
4) The line joining the centre of gravity and centre of gravity of the liquid displaced by the body when immersed in the liquid.
5) The line joining the centre of gravity and centre of Buoyancy is called centre line.
6) Metacentre- It is the point where vertical line passing through the centre of Buoyancy intersects the central line.