Question

lets say there are 3 charges of which 2 are positive and anegative one is in btwn the 2, how do i find the net force ?i mean how do i know their directions.

Answer 1

find the force on each charge, probably using vector addition and then sum the vectors to produce the net force, you can usually find the angle (direction) of the net force by finding the angle using a trig function like tan for example

Answer 2

I hope that is helpful, its difficult to answer more specifically without a diagram and/or exact problem example :)