In a certain region, the earth's magnetic field has a magnitude of5.4 x 10-5 T and it is directed north at an angle580 below the horizontal. An electrically charged bulletis fired north and 110 above the horizontal with a speedof 670 m/s. The magnetic force on the bullet is 2.8 x10-10 N, directed due east. Determine the bullet'selectric charge, including it's algebraic sign (+ or -).