Editing Magnet (section)

====Pull force of a single magnet====
The strength of a given magnet is sometimes given in terms of its ''pull force'' — its ability to pull [[Ferromagnetism|ferromagnetic]] objects.<ref>{{Cite web|url=https://www.kjmagnetics.com/blog.asp?p=how-much-will-a-magnet-hold|title=How Much Will a Magnet Hold?|website=www.kjmagnetics.com|access-date=2020-01-20}}</ref> The pull force exerted by either an electromagnet or a permanent magnet with no air gap (i.e., the ferromagnetic object is in direct contact with the pole of the magnet<ref>{{Cite web|url=https://www.duramag.com/techtalk/tech-briefs/magnetic-pull-force-explained/|title=Magnetic Pull Force Explained - What is Magnet Pull Force? {{!}} Dura Magnetics USA|date=19 October 2016|language=en-US|access-date=2020-01-20}}</ref>) is given by the [[Maxwell equation]]:<ref>{{Cite book|title=Materials Handbook: A Concise Desktop Reference|last=Cardarelli|first=François|edition=Second|year=2008|page=493|publisher=Springer|url=https://books.google.com/books?id=PvU-qbQJq7IC&pg=PA493|isbn=9781846286681|url-status=live|archive-url=https://web.archive.org/web/20161224182756/https://books.google.com/books?id=PvU-qbQJq7IC&pg=PA493|archive-date=2016-12-24}}</ref>
:<math>F={{B^2 A}\over{2 \mu_{0}}}</math>,

where:
* ''F'' is force (SI unit: [[newton (unit)|newton]])
* ''A'' is the cross section of the area of the pole (in square meters)
* ''B'' is the magnetic induction exerted by the magnet.

This result can be easily derived using [[Force between magnets#Gilbert model|Gilbert model]], which assumes that the pole of magnet is charged with [[magnetic monopole]]s that induces the same in the ferromagnetic object.

If a magnet is acting vertically, it can lift a mass ''m'' in kilograms given by the simple equation:

:<math>m={{B^2 A}\over{2 \mu_{0} g}},</math>

where g is the [[gravitational acceleration]].