Consider the system pictured in the figure below. A 14.2-cm horizontal wire of mass 13.7 g is placed between two thin, vertical conductors, and a uniform magnetic field acts perpendicular to the page. The wire is free to move vertically without friction on the two vertical conductors. When a 4.50-4 current is directed as shown in the figure, the horizontal wire moves upward at constant velocity in the presence of gravity. e v t (a) What forces act on the horizontal wire? {Select all that apply.) [ gravitational force magnetic force [ electric force (b)) Under what condition is the wire able to move upward at constant velocity? (