• Friction is caused by the irregularities on the two surfaces in contact.
  • Even those surfaces which appear very smooth but microscopic view show those irregularities.
  • The irregularities of the two surfaces get interlocked. We have to apply force to remove the interlocking.
  • So the force of friction is greater if a rough surface is involved.
  • The friction force will increase with the increase in weight. Example: It is easier to drag a mat when nobody is sitting on it than a person is sitting on it because friction increases with an increase in weight.
  • Rougher surface offers more force of friction.
  • It acts in a direction opposite to the direction of motion.
  • It depends on the mass of the body.
  • It depends on the surface's nature, as smooth surfaces have fewer irregularities and thus less friction. As a result, moving an object to a smooth surface is easier than moving an object to a rough surface

Which one is easier to hold in hand: An Earthen Pot or a Glass Tumbler. Why?



Because of the smoother surface, the Glass Tumbler creates less friction and it is not easier to hold. On the other hand, an earthen pot has a rougher surface which creates more friction and thus makes it easier to grip.

Factors that can affect Friction

 Contact between two surfaces
  • The irregularities of a surface: If we move an object with has an irregular or rough surface on another surface that is also irregular, the force of Friction will be high in this case and the movement of the object would be restricted.
  • The regularity of a surface or its smoothness: If the surfaces of either the object are smooth, the force of Friction would be less and the object would move easily over the surface. Even smooth surfaces have a certain irregularity.
  • If two surfaces are pressed hard: the force of Friction increases between two surfaces if they are pressed hard and hence the movement of the object becomes restricted. However, if there is no pressure the object can easily move.
 Factors Affecting Friction