A gravity knife is a folding knife which can be opened solely by the force of gravity or centripetal force. Also implied is usually some kind of locking mechanism to keep the blade locked in place once opened. These tend to be illegal in places that care about weapons restrictions.
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This weapon article is a stub. You can help Wikipedia by expanding it (http://www.wordiq.com/definition/Gravity_knife).
Example Usage of Gravity
amywithlemon: It's not often I recommend music to you guys, but, for kicks, download "Gravity's Rainbow" by the Klaxons. Great for a run. Or 'whatever'.
Sarah_inthe_Sky: "DON'T DO THAT, WE'VE GOT A Gravity HAMMER"
KayLee2097: Black Firday Sale New Deal From : Gravity Defyer 11/27/2009 http://bit.ly/6m674B
