Suppose a conducting rod $($mass $=333$ g$,$ resistance $=5\mathrm{.}57)$ rests on two frictionless and resistanceless parallel conducting rails a distance of $18$ cm apart in a uniform magnetic field of $3$ T that is perpendicular to both the rails and the rod. The rod begins at rest, and a source of emf equal to $43$ V is connected across the rails. How fast will the rod be moving after $4\mathrm{.}15$ s have elapsed?