3. A bar is moving at a constant velocity u = uf, as shown in the gure. The length of the bar is E. The bar has a negligible diameter and has charge Q uniformly distributed across its length. Calculate the retarded scalar and Y vector potentials, d) and H, respective- ly, at the point x0 on the x-axis. Hint: You can use the Lienard-Wiechert potentials of a point charge