Solving a problem in physics section 39 paragraph 23 el

23. two smooth copper bars set at an angle α to the horizontal, slides under gravity copper jumper mass m. On top of the bus are closed to the capacitor capacitance C. The distance between the tires l. The system is in a uniform magnetic field induction B perpendicular to the plane in which the bridge moves. Resistance tires, jumpers and sliding contacts, as well as self-induction loop, is negligible. Find the acceleration of the jumper.