Task 30149.

Two conductive rails installed at an angle a = 30 ° to the horizontal, slides down the metal bar weighing m = 1 kg. The surrounding space of the bus created a uniform magnetic field with induction B = 1 T perpendicular to the plane in which the bar is moved. Above the bus connected with the conductor resistance R = 1 ohm. The coefficient of friction between the surfaces of the tires and the bar m = 0.2, the distance between the tires l = 1 m. Find the steady value of the velocity v of the bar.