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Hard Mag. Field question need assistance

  1. Mar 9, 2005 #1
    Two long, parallel wires hang by 4.00-cm-long cords from a common axis. The wires have a mass per unit length of 1.50×10-2 kg/m and carry the same current in opposite directions.

    What is the current in each wire if the cords hang at an angle of 6-degrees with the vertical?

    Basically,,,,,I have no idea how to approach or solve this proble. All I know is the curremt should be positive becuase the currents in the wires are opposite each other.

    aghhh help me please
  2. jcsd
  3. Mar 10, 2005 #2


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    QUOTE=Elbhi:" All I know is the curremt should be positive becuase the currents in the wires are opposite each other."

    Wat do you mean...?It's not an magnetism problem,its a STATICS problem.What forces act on the wires...?

  4. Mar 10, 2005 #3
    Ya, draw free body diagrams and solve it like you would a normal statics problem. Once you know the forces on the wire then you can calculate everything you need to.
  5. Mar 18, 2005 #4

    You must clear your mind on a few concepts. Current is not positive or
    negative, it flows in a particular direction like water in a pipe.
    Voltage is either positive or negative and is like the pressure in the pipe.

    You need to know a few things:

    1) How much force does one wire exert on the other as a function of their
    distance apart
    2) How much do the wires weigh
    3) How do the wires deflect when you apply a force to them

    If you combine all these into a suitable set of equations, the answer will
    fall out.
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