A conducting bar rests over two metal rails that are connected to a battery. The entire con- fipuration i1s placed in an external, uniform magnetic field. If a current is pumped through this circuit it will interact with the external magnetic field and cause the bar to slide. For this problem ignore friction and air resistance. The length of the bar is L = 1 [m], the magnetic field strength is B = 10 [T], and the current in the circuit is [ = 107 [A]. a) Write down the magnetic force on the conducting bar. b) Show with a cross product that it must point to the right. ) What is the kinetic energy of a 1 [kg] bar that is traveling at v = 343 [m/s]? This is the speed of sound. d) How long does the rail need to be to get to this speed