### Newtonian Law of Attraction

Newtonian Law of Attraction :-

Every particle of matter attracts every other particle of matter with a force which varies directly as the product of the masses of the particles and inversely as the square of the distance between them .

Let   m1 gm   and    m2 gm   be the masses of the two particles placed at a distance of the    r cms   .  Then the force of attraction      between them is such that

F   varies   m1 , m2    when is constant .

F    varies   1/(r.r)    when  m1 , m2    are constant

Therefore by theorem of joint variation   F   is given by

F  varies   (m1m2) /(r.r)

i.e.   F= gama  (m1m2)/(r.r)

where   gama   is called constant of attraction  .

So , the Newtonian law of attraction is

Attraction = gama (product of mass)/(square of distance)

Important :-

--------  The attraction of a rod   AB   at an external point    is the same as that of the arc of a circle , of like material with center   P   and of radius equal to perpendicular from   P   on   AB   , which is intercepted by the lines   PA   and    PB   .