Subject: Electro Magnets: could they be used to generate a shield?

would it be possible to use electo magnets postioned on something like a 
building to make a kind of force field? using trillions of magnetically charged 
particles, and turning the magnets on and off at regular times, and alternating 
the order of the magnets, would it be possible to create a swirling defensive 
matrix that would shred, or at least slow a bullet or something before it hit's 
the protected object?

Re: Electro Magnets: could they be used to generate a shield?