What is friction ? / types of friction /Angle of friction /law of friction and other details ...

 Friction - 

                  the property of two tengent objects which produce a tangential stress on their tengent points that gives the pids  a what prevent friction  or sliding on another is called friction or force , the meaning of friction is often considered to be the force of friction .


Types of friction -

                   There are often two types of friction ....... (1) static fiction (2) Dynamic friction 

(1) Static friction - If two objects touch each other are in equilibrium ,they arise at the tengent point is called static friction .

(2) Dynamic friction - the friction arising at tge tengent point of one body at the point of sliding or moving at the other body is called dynamic friction . 

 Limiting friction  -   If one body is in state of sliding an another body ie in the state of marginal equilibrium  . friction arising at their touch point is called extreme friction or limiting friction . If this state the amount of friction is maximum. 

Angle of friction -  The angle between the resultant response and the reaction at the point of contact  b/w two objects when they are in contact with each other is called angle of friction .It is donated by tan⋌ = tan α.     Hence ,
  


Coefficient of friction   -  the ratio of the peak friction force and the reciprocal reaction at the tengent point of two objects when they are in the objects the states of marginal equilibrium is called the coefficient of friction . It is often denoted by μ.
                Hence , μ = tan α (friction angle )

Law of friction - the following laws of friction are based on experience only .these rules determine the magnitude ,direction and nature of the friction frame.

(1) the direction of frictional force of the tengent point of two bodies is always opposite to the direction of motion of the bodies or inclusions . the force of friction always acts parallel to the surface touching the tactile surface . 

(2) In the equilibrium states the magnitude of friction is only that which is capable of preventing the body from moving, frictional force is safe adjusting .

(3) there is a definite ratio of the peak friction force and the body's normal response .that is the coefficient of friction is fixed which depend on the nature of the substance . Hence F = μR

(4) So long as the response is unchanged ,tge peak friction force  does not depend on the area or size and nature of the touching surface .

(5) The value of the force of friction depend on the surface touch and the material on that surface .

(6) The value of coefficient of friction remains constant till the average speed but its value decrease slightly as vthe apper increases. 

(7) The value of coefficient of friction is somewhat less in the moving state then in the static state . It does not depend on the velocity of the bodies.
                  F = μR = tan α R


Angle of repose - 
                                 An angle that makes a bottom plane horizontally when a body placed on it is in a state of sliding down or in a state of marginal equilibrium is called angle of repose . it is often denoted by α (alfa )

Cone of friction - In the case of two bodies touching each at a point O, the cone whose (1) vertex is at the tengent point O (2) the response at the tengent point O, is the axis of the cone and (3) the half angle of cone is equal to the friction angle and the friction at the point O is called the cone .
Clearly, In the state of marginal equilibrium the working will be inside the surface of this cone and all other conditions inside the cone .



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