Posted by Sarah (C) on .
I want to understand this concept more than anything so advice as well as hints to solve this problem are greatly appreciated.
26. Two fixed charges, 4.0E6 C and 5.0E6 C, are separated by a certain distance.
a) is the net electric field at a location halfway between the two charges
1) directed toward the 4.0E6 C charge
2) zero
3) directed toward the 5.0E6 charge.
30)Two charges of +4.0 E6 C and +9.0 E6 C are 30 cm apart. Where on the line joining the charges is the electric field zero?

physics 
bobpursley,
a. E is the direction a + charge goes, so it will be directed to the 5E6charge
30)
k4E6/x=k9E6/(.3x)
solve for x, the distance in meters from the smaller charge.