A uniformly charged rod (length L, charge density λ) slides out the x axis at constant speed v. At time t=0 the back end passes the origin (so its position as a function of time is x=vt, while the front end is at x=vt+L). Find the retarded scalar potential at the origin, as a function of time, for t>0. [First determine the retarded time t1 for the back end, the retarded time t2 for the front end, and the corresponding retarded positions x1 and x2.] Is your answer consistent with the Li\'{e}nard-Wiechert potential, in the point charge limit (L≪vt, with λL=q)? Do not assume v≪c.