add array
made the magnet as 10 individual magnets instead of the original single magnetic dipole
made variable magnetZ as slider that controls the model, it was not easy, cant recall what i did now.
magnetLength as slider
position 10 magnets across the magnetLength equally spaced
variable coilZ as slider that controls the model
add current and individual current to debug a problem with original codes that cause a unusual spike in the tension = voltage.
redo the voltage and seems to be okay now

time to sleep. 1 am
got workshop later :) at 8 am

more changes
made the ball freeFallZ = magnetZ[n/2-1]; // match centre of magnet
made n = 30 for smoother graph

found this great activity by Pasco