Final answer:
The force on a positive moving charge in a magnetic field is determined by the right hand rule 1 (RHR-1) and is perpendicular to both the velocity and the magnetic field.
Step-by-step explanation:
The direction of the force on a positive moving charge in a magnetic field is determined by the right hand rule 1 (RHR-1). To determine the direction of the force, point your right thumb in the direction of the velocity and your fingers in the direction of the magnetic field. The force will be perpendicular to both the velocity and the magnetic field, and can be determined by the direction your palm would push. For a charge moving in the xy plane with velocity components in both the positive x and y directions, and a magnetic field pointing in the positive direction, the force will be in the -z direction.