Figure 29-47 shows, in cross section, four thin wires that are parallel, straight, and very long. They carry identical currents, in the directions indicated. Initially all four wires are at distance d = 13.5 cm from the origin of the coordinate system, where they create a net magnetic field B.

the figure is here: http://answerboard.cramster.com/physics-topic-5-199667-0.aspx



Fig. 29-47
(a) To what value of x must you move wire 1 along the x axis in order to rotate B counterclockwise by 25°? (cm)
(b) With wire 1 in that new position, to what value of x must you move wire 3 along the x axis to rotate B by 25° back to its initial orientation? (cm)



I really don't know how to get started. Any help is greatly appreciated.

2/28/2008 8:48:13 AM