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 FRICTION

The resistance offered by the surfaces that are in contact with each other when they move over each other.







Friction works in the opposite direction in which the body is moving making the body slow down. Friction is useful in most of the cases. Friction is also dependent on external factors.


CAUSES

When we see any object, we can see the smooth surface but when the same object is viewed under a microscope, it can be seen that even the smooth appearing object has rough edges. Tiny hills and grooves can be seen through the microscope, and they are known as irregularities of the surface.

So, when one object is moved over the other, these irregularities on the surface get entangled giving rise to friction. More the roughness, more will the irregularities and greater will be the force applied.


EXAMPLES

  • Friction finds application when matchsticks are ignited.
  • Motion of pistons in a cylinder is an application of friction.
  • It is possible to write on books and board as there is friction between pen and the board.

TYPES OF FORCES

  1. CONTACT FORCES
  2. NON CONTACT FORCES

CONTACT FORCES


Contact force is a force that is applied by objects in contact with each other. The contact force acts on a point of direct contact between the two objects

EXAMPLES
  • FRICTIONAL FORCE


NON CONTACT FORCES


A non-contact force is a force applied to an object by another body that is not in direct contact with it. Non-contact forces come into play when objects do not have physical contact between them or when a force is applied without any interaction.

EXAMPLES
  • GRAVITATIONAL FORCE






  • ELECTROSTATIC FORCE


  • MAGNETIC FORCE


Difference between Contact and Non-Contact Forces

Contact forcesNon-contact force
Contact force occurs due to the contact between two different objects.Non-contact force occurs due to either attraction or repulsion between two objects such that there is no contact between these objects.
There is no field linked with the contact force.There is always a field linked with non-contact force.
The frictional force is an example of a contact force.Gravitational force is an example of a non-contact force.

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