Forces on Wires
cross section of three wires carrying unknown currents is shown above. You can
click-drag the wires and the black arrow represents the force experienced by
many wires have a current that points out of the page?
Reference: See Giancoli-PA: 20-6, Giancoli-SE: 28-2.
Cannot determine, not enough information. There are three wires, so how to
begin? Students first need to realize that a systematic approach will serve them
well in this exercise. Consider two wires at a time with the third as far from
the two as possible. Given that like currents (currents pointing in the same
direction) attract and opposite currents repel, students can figure out that two
of the wires have currents pointing in the same direction. However, this is not
enough to determine whether these currents are into or out of the page.
Script Author: Mario Belloni