Which velocity does the electrons have when leaving the electric field?

In a previous chapter we have seen, the the electrons are not accelerated in x-direction. They move with constant speed in x-direction within the plate capacitor.
We have also seen that the electrons are accelerated in y-direction. So the electron velocity in y-direction changes while moving through the plate capacitor.

Tasks:

a) Calculate the acceleration ay acting on the electrons inside the plate capacitor in y-direction.
b) Calculate the electron velocity vy when leaving the plate capacitor.
c) Calculate the resultant velocity vres of the electrons when leaving the plate capacitor.
Given:
Velocity vx = 4,2·107 m/s
Plate Voltage Vp = 2000 V
Plate Distance d = 0,06 m
Length of Plate Capacitor l = 0,12 m
Charge of Electron e = 1,6·10-19 C
Mass of Electron m = 9,1·10-31 kg
Electron velocity when leaving the plate capacitor
equation of motion in y-direction
$$\begin{equation}y(t)=\frac{1}{2}a_y\cdot t^2\end{equation}$$
$$\begin{equation}v_y(t)=a_y\cdot t\end{equation}$$
$$\begin{equation}a_y(t)=\frac{F}{m}=\frac{V_{\text p}\cdot e}{m\cdot \text{d}}\end{equation}$$