Chapter 22.3, Problem 22.2QQ

A charged particle is moving perpendicular to a magnetic field in a circle with a radius r. (i) An identical particle enters the field, with $\stackrel{\to }{v}$ perpendicular to $\stackrel{\to }{B}$, but with a higher speed than the first particle. Compared with the radius of the circle for the first particle, is the radius of the circular path for the second particle (a) smaller, (b) larger, or (c) equal in size? (ii) The magnitude of the magnetic field is increased. From the same choices, compare the radius of the new circular path of the first particle with the radius of its initial path.