Charge Moving in a Cyclotron Orbit A particle of charge q and mass m moves in a region of space where there is a uniform magnetic field B - Bok (i.e., a magnetic field of magnitude Bo in the +z direction). (Figure 1) In this problem, neglect any forces on the particle other than the magnetic force. B = Bok This force will cause the path of the particle to curve. Therefore, at a later time, the direction of the force will O have a component along the direction of motion O remain perpendicular to the direction of motion O have a component against the direction of motion O first have a component along the direction of motion; then against it; then along it; etc