4. Suppose we have a stationary external magnetic field Bo. We have a positively charged particle of charge |qo| and mass mo. Initially, it is moving vertically down with speed

|vol and no horizontal velocity. The particle can move freely in x and y directions. (a) How does the particle velocity in the vertical and horizontal directions change over time?Provide an expression for v, and vx. (Two plots, two expressions)Vy