Apart from the trivial elements of the motion equation (m z'' = -kz -mg), I am required to find the force produced by the Eddy currents induced by the moving magnet. To do so, I calculated the magnetic flux through the hole plate:
For a magnet:
Bz=μo m 4π. 2z^2−r^2/(z^2+r^2)^5/2
so
Φ = a→ +∞...