Friction - Law of Motion


When two objects are in contact and one moves or has intension to move with respect to other then a force develop between the two oppose it this force is friction.



  • Friction act along the surface 
  • Friction is an electrical force


There are two types of friction :


  • Static friction : In static friction has two types


  1. a) Auto adjusting friction.        
  2. b) Limiting Friction


  • Kinetic Friction : In kinetic friction has two types 



  1.   Sliding Friction    
  2.   Rolling Friction




  •  If body is at rest and no pulling force is acting on it , force of friction is zero. 
  •  If a force applied to move a body and it does not move , the friction develop is called static friction which is equal in magnitude and opposite in direction to the applied force ( self adjusting force) 
  • If a force applied to move a body and it moves the friction develop is called dynamics or kinetic friction 
  • When a body rolls or rotate on the surface of another body friction develop is called rolling friction 
  • It is due to deformation at the point of contact and depends on area of contact.


  • If you are walking due to east the feet slides relatively due to west so the friction force due to east.


  • Engine is connected to rear wheel of a car. When the car is accelerated, direction of frictional force on the rear wheel will be in the direction of motion.


  • In cycling, the force exerted by the rear wheel on the ground make the force of friction to act in the forward direction.


  • When pedaling is stopped, the frictional force in backward direction for both the wheels.




Post By : Faiz Ahmad Faiz 21 Feb, 2020 1732 views Physics Laws of Motion and Friction