Posted by echem on .
Consider three charged particles placed along the xaxis. The particle with q1 = 9.27 nC is at x = 7.66 m and q2 = 4.82 nC is at x = 2.64 m. Where must a positive charge, q3, be placed such that the resultant force on it is zero?
I know F3= F13+ F23
(net force on charge q3 = force 1 on 3 + force 2 on 3)
and that you determine F13 and F23 using columbs law:
ke(q1*q2)/r^2
So you would, Write an expression for the force that each of the other two charges exert on q3 and then set the value of the total force equal to zero.
but I don't know what values of r I would use for each expression.

phYsics 
Brit,
Sorry no help is online right now, and i cant help you on this one. Sorry!

phYsics 
liberation,
The resultant force cannot be zero since all are positive charges