I was wondering how strong a magnet should be in order to be able to horizontally attract 0.2 Kg of pure iron at a distance of 0.3 M. Since I know nothing about magnets, I started looking for companies that provide magnets, and what different ones they offer, and I decided to pick a bar magnet. My problem here is that I couldn't relate the formulas I found online to calculate the strength of the required magnet to the properties given on magnet providers website.
The formula I found was: (is it true in the first place?)
$F= \mu m_1m_2/4\pi r^2 $
"$m_1$ and $m_2$ are the magnitudes of magnetic poles" How do I relate $m_1$ and $m_2$ to the information that magnets providers give? The information that was on the providers website were: about Magnetic Face area, Thickness, Grade, Performance, vertical pull and slide resistance!
Lets assume normal air separation for the $\mu$.