It is clearly possible to change the direction of an objects movement without doing work on it, if you consider forces perpendicular to the direction of movemen

It is clearly possible to change the direction of an objects movement without doing work on it, if you consider forces perpendicular to the direction of movement. In other words, you can change the direction of the velocity vector without doing work, as long as the magnitude stays the same (ignoring potential energy here). In fact, a magnetic field is unable to do work, since it always acts perpendicular to the direction of movement of the charge that it acts upon.