Chapter 27, Problem 37P

(III) A particle with charge +q and mass m travels in a uniform magnetic field $\stackrel{\to }{B}=B_0\hat{k}$. At time t = 0, the particle’s speed is υ₀ and its velocity vector lies in the xy plane directed at an angle of 30° with respect to the y axis as shown in Fig. 27–47. At a later time t = t_α, the particle will cross the x axis at x = α. In terms of q, m, υ₀, and B₀, determine (a) α, and (b) t_α.