A wire having a mass per unit length of 0.600 g/cm carries a 1.60-A current horizontally to the south. (a) What is the direction of the minimum magnetic field needed to lift this wire vertically upward? O northward eastward O southward O westward (b) What is the magnitude of the minimum magnetic field needed to lift this wire vertically upward? 367.5 X Your response is off by a multiple of ten. TA rod of mass 0.720 kg and radius 6.00 cm rests on two parallel rails (see figure below) that are d = 12.0 cm apart and L = 45.0 cm long. The rod carries a current of / = 32.0 A in the direction shown and rolls along the rails without slipping. A uniform magnetic field of magnitude 0.420 T 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? (Assume that the rod is of uniform density.) m/s