Electric field - Finding the charges

[rm_girl]

Homework Statement

Two point charges q1 and q2 are held 4.00cm apart. An electron released at a point that is equidistant from both charges, undergoes an initial acceleration of 8.05×1018m/s² directly upward in the figure, parallel to the line connecting q1 and q2.

Homework Equations

E=k(q/r²)
F=k(q/r²)
E=F/q

The Attempt at a Solution

I already know what the answers are.
q1 = 5.97x10^-6 C
q2 = -5.97x10^-6 C

I just have no idea how they got those answers. Could someone please explain?

 

[ehild]

Homework Statement

Two point charges q1 and q2 are held 4.00cm apart. An electron released at a point that is equidistant from both charges, undergoes an initial acceleration of 8.05×1018m/s² directly upward in the figure, parallel to the line connecting q1 and q2.

Homework Equations

E=k(q/r²)
F=k(q/r²)
E=F/q

The Attempt at a Solution

I already know what the answers are.
q1 = 5.97x10^-6 C
q2 = -5.97x10^-6 C

I just have no idea how they got those answers. Could someone please explain?

Both charges exert some force on the electron. Draw the force vectors. What can you say about their direction?

ehild