Page 34 - Electrostatics-11
P. 34

© GC Shiba
                                                           
                                              =     =                      ,      =           
                                                         
               Also,
                                                           
                                              =     =                      ,      =           
                                                         


                              ⃗⃗⃗
        Magnitude of   

                                                                         2
                                                               2
                                                                                   2
               From right angle triangle CAD,         =      +     
                                                                2
                                                                          2
                                              = (     +     ) +     
                                                                  2
                                                                                  2
                                             = (   +           ) + (          )
                                            =    + 2             +              +             
                                                  2
                                                                          2
                                                                                2
                                                                                               2
                                                                                         2
                                                                                  2
                                                                          2
                                                                                             2
                                                  2
                                             =    + 2             +    (          +          )
                                                 2
                                                                                2
                                                        2
                                                  =    + 2             +   
                                                 = √   +    + 2            
                                                         2
                                                                2
                                                                                          ⃗⃗
                                            It  gives the magnitude of resultant   .
                           ⃗⃗⃗
        Direction of   
                                                                    ⃗⃗
                                                                             ⃗⃗
               Let β be the angle made by the resultant   with   
               Now, from triangle CAD,
                                                                                          
                                                     =      =              =
                                                                  +              +          
                                                                             
                                                   =        −1  (              )
                                                                   +           
                                                                                       ⃗⃗
                                            It gives the direction of resultant   .


        3. Polygon law: If the number of different vectors acting on a
            particle  simultaneously  represent  the  many  sides  of  a                                     ⃗
            polygon in terms of both magnitude and direction, then the                           
                                                                                                ⃗
            closing line taken in opposite order will be their resultant.
                                                 ⃗⃗
                                                             ⃗
                                      ⃗⃗
               Mathematically,    =    +    +   ⃗ +    +   ⃗                                   ⃗                 
                                            ⃗

                                                                                                       
                                                                                                     ⃗
        Resolution of Vector: The process of splitting of a vector into number of its
        components  in  specified  direction  is  called  resolution  of  vector.  It  is  exactly

        opposite phenomenon of composition of vectors.




        11                                                                                      Mechanics
   29   30   31   32   33   34   35   36   37   38   39