controls:

acceleration voltage V_a

plate voltage V_p

Because there is no force in horizontal direction, the electrons perform a linear motion without acceleration in this direction.
In vertical direction there is a constant force caused by the electric field. So electrons perform a linear motion with constant acceleration in this direction.
So equations of motion shown on the right can be used.

equation of motion in x-direction	equation of motion in y-direction
$x(t)=v_0\cdot t$	$y(t)=\frac{1}{2}a_y\cdot t^2$
$v_x(t)=v_0$	$v_y(t)=a_y\cdot t$
$a_x(t) = 0$	$a_y(t)=\frac{F}{m}=\frac{V_{\text p}\cdot e}{m\cdot \text{d}}$

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