Find force on short dipole `P_(2)` due to short dipole `P_(1)` if they are placed a distance r apart a shown in figure.

Explanation

`F_("net")=q_(2) E (x+dx)-q_(2) E (x)`
`F_("net")=q_(2) ((E(x+dx)-E(x))/(dx))dx`
or `F_("net")=(P_(2)) ((dE)/(dx))`
(Usually this dormula is valid when the dipole is placed along `vec(E)`. However, in this case also, we are getting the same formula)
`:. F_("net")=(P_(2)) (d/(dr) ((KP_(1))/r^(3)))`
`implies F_("net")=(3KP_(1)P_(2))/r^(4)` (in magnitude) & (direction upwards)