Q28: A metal rod of mass m slides without friction along two parallel horizontal rails, separated by a distance , and connected by a resistor R, as shown in Figure P31.26. A uniform vertical magnetic field of magnitude B is applied perpendicular to the plane of the paper. The applied force shown in the figure acts only for a moment, to give the rod a speed v. In terms of m, ,, R, B, and v, find the distance the rod will then slide as it coasts to a stop.