How to calculate vertical electron deflection between two charged plates?

[Molly]

Homework Statement

In the problem, an election is moving though 2 charged plates
vertical electric field amount is given and its perpendicular to the electron’s original horizontal velocity. The initial speed of the electron is given and the horizontal distance it travels is given. Then it asks for the charge density, the vertical deflection, and the vertical component of Vf.

Homework Equations

E=sigma/ 2* epsilon 0.

The Attempt at a Solution

So i think I got the charge density correct, hopefully. I used the above equation to calculate sigma. What I am stuck on is how do I calculate vertical deflection? I feel like this is something really stupid to be confused about, but I don't know how to start it.

 

[haruspex]

how do I calculate vertical deflection?

It's a uniform field so produces constant acceleration, just like in Earth's surface trajectory problems.
Does that help?