SUPER Hard Physics Problem!!-PLEASE Help??

Question

A long horizontal wire carries a current of IT = 48.8 A. A second wire (I), made of 2.50 mm diameter copper wire and parallel to the first but L = 13.3 cm below it, is held in suspension magnetically, as seen in the figure below. What is the current in the lower wire (Use right as the positive direction)?

What is the current in the lower wire if the second wire is suspended L = 13.3 cm above the first due to the latter's field.

How do you solve this complicated problem?? I am so lost and confused.





Here is a diagram: http://i151.photobucket.com/albums/s126/beautyqueenjustine/gian2056.gif

Answer 1

For starters, currents in the same direction attract; currents in the opposite direction oppose.

Since the second wire is suspended, it is attracted to the first wire. Assuming that the first wire cannot move, there has to be an opposing force keeping the second wire from attaching itself to the first. That force is gravity acting on the mass of the copper. Knowing the diameter of the copper, and the acceleration of the wire due to gravity you should be able to calculate the current that is keeping the wire suspended.

Answer 2

This is actually a very simple question.
If there is no place for the current to flow then there will be 0 amps in the second wire. Because the second wire is held in suspension magnetically we know that it is isolated.

Current can only flow in a completed circuit since energy is never lost. Crosstalk occurs when current in one transmission line is induced into another transmission line. That is a function of both distance apart and the distance of the parallelism. In printed circuit board design we are very concerned about this, however your question does not mention any length the wires are parallel. Since the answer can be solved by the fact the wire is isolated. We know that no current can flow in it.