lets discuss principle of superposition for
electric forces. this quit an important principle,
to be used in various numerical application.
let us first write down its statement. it
states. when in a system. there are. more
then two charges. then net electric force.
on any charge . can be given by. vector sum
of. all individual, forces. acting on it.
by, independent. charges of system. this quite
an important rule. lets discuss it with the
help of an application like say we are having
a charge q-not. and in its surrounding there
are few charges q 1. q 2 and q 3 place. and
say there are many charges. now in this situation
say if q 1 is located at a distance r 1. q
2 is at a distance r 2 q 3 is at a distance
r 3. and say if we define , these distances
with respect to q 1 q 2 q 3 in terms of, positions
vectors like, these r 1 r 2 and r 3 are the
position vectors, of q-not with respect to
the three charges, now in this situation say
if q 1 is applying a force f 1. onto q-not,
q 2 is independently exerting a force f-2
onto q-not and q 3 is exerting a force f-3
onto this q-not . and these are the independent
columbian forces applied by the three charges
on q-not. and we can write f net on q-not
, vectorially can be given by the vector sum
of all the forces acting on it that is f 1
plus f 2 plus f 3. even, we can extend it
to any number of charges, so we substitute
the values the net force acting on q-not can
be given as, it is, k q 1 q 2 by r 1 cube,
k q 1 q-not by r 1 cube r 1 vector plus , k
q 2 q-not by, r 2 cube r 2 vector plus and
so on . here i am using the vector form of
coulomb’s law we already studied. this is
the way we can find out a net force acting
on the charge particle. due to all the other
charges present in the surrounding. for numerical
application it is always easier, to resolve
all these forces and two mutually perpendicular
component and by using standard unit vectors
we can calculate the , resulting force will
see, this same calculation in various numerical
examples also.
