What is the Magnitude of the Electric Field to Just Miss the Upper Plate?

[Digdug12]

Homework Statement

An electron is projected with an initial speed v_0 = 2.00×106 {\rm m/s} into the uniform field between the parallel plates in the figure (Intro 1 figure) . Assume that the field between the plates is uniform and directed vertically downward, and that the field outside the plates is zero. The electron enters the field at a point midway between the plates.
If the electron just misses the upper plate as it emerges from the field, find the magnitude of the electric field.
(length of plates = 2cm, distance between plates=1cm)

Homework Equations

F=eQ
y=.5at^2+V(t)+y(initial)

The Attempt at a Solution

Ok, so first I tried to force on the charge from the electric field, but I don't know the electric field. So then I tried the position equation to find Acceleration but I don't know the time it took to travel through the plates, I would be able to find that but I am not sure if the velocity in the x direction stays the same? (the direction parallel to the plates)

 

[rl.bhat]

As you have said, the velocity in the x direction remains the same.