3 rigid rods r joined 2 form an equilaeral triangle ABC of side 1 m .3 particles carrying charges 20 microcoulumb each r attached 2 d vertices of triangle .d whole system is at rest in an inertial frame .d resultant force on the charged particles at A has what magnitude?

let A,B,C are the vertices of the tringle.......

let force due to charge at A on B is f=kq^2/a^2=kq^2               (a=1m)

let force due to charge at C on B IS F=kq^2/a^2=kq^2

 resultant force is R=sqrt(f^2+F^2+2Ffcos60)          

     R=fsqrt3                   (f=F)

       =kq^2sqrt3

       =3.6sqrt3 N