A rod of mass m and radius R rests on two parallel rails that are a distance d apart have a length L. The rod carries a current I in the direction shown and rolls along the rails without slipping. A uniform magnetic field B is directed perpendicular to the rod and the rails. If it starts from rest, what is the speed of the rod as it leaves the rails? (Use any variable or symbol stated above as necessary.)
v = .......... m/s