Wagner Lipnharski wrote:
>
> What is the most positive way to block magnetic field using a 5mm *any
> material* board?
> Take a look at the picture and tell me why it doesn't work.
> http://www.ustr.net/jpg/moto1.jpg

There is no such a material, but Your drawing is also quite wrong from
the magnetics field point of view.

Take a look at:
http://members.aol.com/GMagnetics/

David Meeker is offering his simple but _powerfull_ program
'Finite Element Method Magnetics' for free.
You can analyze Your drawing with it.


> Ok, for those who don't believe in magic, what about this one?
> http://www.ustr.net/jpg/moto2.jpg
> Just complete the blanks:
> Because the .. and .... ......... is the same.

I used to draw similar machines when I was twelve.
(None of them works of course ;-).

Try to calculate Your vectors with better accuracy and then add
them all together.

--
Regards
           Petr Krc