Question: The three diagrams in Fig. show a positive charge q moving with velocity v in different directions relative to the magnetic field B. The diagram uses the customary convention of dots representing B pointing out of the plane of the page (tips of arrowheads), and ×'s representing B pointing into the plane of the page (tail feathers of arrows). For each case, what is the direction of the force?
Fig. Three examples of charged particles moving in a uniform magnetic field. The dots mean that the magnetic field B points out of the page; the x's mean that the magnetic field B points into the page.