  We present a relativistic model for the motion of charged particles in
rotating magnetic field lines projected on to a plane perpendicular to the
rotation axis. By making an approximation that the projected field lines are
straight, an analytical expression is obtained for the particle trajectory. The
motive behind developing this model is to elucidate some of the effects of
rotation in pulsar profiles. There is a significant contribution to the
curvature of particle trajectory due to the rotation of pulsar, which is in
addition to the inherent curvature of the field lines. The asymmetry in the
observed pulse shapes can be explained by considering the
aberration-retardation effects. The single sign circular polarization that has
been observed in many pulsars, might be due to the relative orientation of
sight line with respect to the particle trajectory plane.
