A metal rod of length 12 cm and mass 70 grams has metal loops at both ends, which go around two metal poles (Figure 21.95). The rod is in good electrical contact with the poles but can slide freely up...

A metal rod of length 12 cm and mass 70 grams has metal loops at both ends, which go around two metal poles (Figure 21.95). The rod is in good electrical contact with the poles but can slide freely up and down. The metal poles are connected by wires to a battery, and a 5-ampere current flows through the rod. A magnet supplies a large uniform magnetic field B in the region of the rod, large enough that you can neglect the magnetic fields due to the 5-ampere current. The magnetic field is oriented so as to have the maximum effect on the rod. The rod sits at rest 4 cm above the table. What are the magnitude and direction of the magnetic field in the region of the rod? Briefly explain your work, including a diagram.