LAW OF FORCES

LAW OF FORCES

@ Force :-

         it is defined as a push or pull that changes or tends to change the state of rest of uniform motion of a body force is a vector quantity have both magnitude and direction

@ Characteristics of force :- 

       - magnitude :-
                the quanlity of a force is called its magnitude
- Direction :-
         the direction force is the direction of line along which it acts
- Nature of force :-
       the nature of force means wheather the force push or pull
- Point of application :-
           it is the point at which force acts on body
- Unit of force :-
       force is the product of mass and acceleration of a body , it is denoted by "F". in which force = m>< a , where m= mass and a= acceleration. there are some system fr expressing the unit of force are

i) absolute unit :-

         an absolute unit of a force may be defined as that force which much produce unit acceleration in a body of unit mass
SI = 1 kg m/sec (Square)= Newton
CGS = 1 gm cm/sec(square) = dyne

ii) Gravtational unit :-

           it may ne defined as that force which must produce an acceleration equal to acceleration due to gravity in a unit of body mass
F= m><a      MKS = 9.8 newton
F= mg            CGS = 980 dyne

# Force system :-

      it is a collection of forces acting simultaneously on a body in one or more planes

# Classification of force system :-

           Force system ( divided into
                                1) Coplaner force                
    1.1) Concurrent                                  1.2) Non concurrent
1.1.1) colliner 1.1,2) non parellel        1.2,1) parellel 1.2.2) nonparellel
                                2) Non Coplaner
     2.1) Concurrent                          2.2) non concurrent
                                         2.2.1) parellel    2.2.2) non parellel

i) Coplaner force system :-

       the force acting constituiting he given system lie in the same plane

ii) Coplaner concurrent collinear force system :-

           all the forces in this system act along the same straight line, they have a common line of action

iii) coplaner concurrent nonparellel force system :-

             in this system all the forces meet at one point and their line of action lie in one plain

iv) coplaner non-concurrent parellel force system :-

          the line of action of all the forces lie in same plane and are parellel to each other these forces may not have the same direction

v) Coplaner nonconcurrent non parellel force system :-

             the line of action of all forces lie in same plane but are not parellel to each other forces may not have same direction

vi) Non-coplaner force system :-

                 the forces constituiting the given system do not lie in the same plane
a) Non coplaner concurrent force system :-
             in this system the line of action of all the forces meet at a point but not lie in the sameplane
b) Non coplaner non-concurrent parellel FS :-
                    in this system the line of action of forces are parellel these factor do not meet at a point and are not in the same plane
c) non planer non concurrent non parellel FS :-
             in this system the line of action of forces are not parellel, these forces do not meet at a point and are not in same plane

@ Parallelogram law of forces :-

             its states that if two forces acting on a particle are represented in magnitude and direction by the two adjacent side of a parellelogram drawn from a point than . these resultant is represented by the parellelogram of diagram passing through that diagram

@ Triangular law of forces :-

             it states that if two forces acting simultaneously on a body are represented in magnitude and direction by the two sides of a triangle than their resultant ir represented in magnitude and direction by the third side taken in opposite order

@ Polygen law of forces :-

           it states that if a number of forces acting simultaneosly are represented in magnitude and direction by the sides f polygon taken in order than their resultant is represented by the closing side of polygon taken in opposite order

@ Principle of Resolved part :-

          alzebric sum of resolved part of a number of co-planer forces in a given direction equal to the resolved part of the resultant in the same direction

@ principle of transmissibility of forces :-

               it states that the point of application of a force may be changed to any other point along the line of action of force without any change in the external affect produced by the force

@ Concept of equilibrium :-

                 if the resultant of force system on a body is zero. the body is said to be in equillibrium

@ equillibrium force :-

                the single force which can balance a force system . it is equal in magnitude but opposite in direction to the resultant of all the forces acting on a body