# Friction - Law of Motion

Friction

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

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