DandelionTheory Posted June 2, 2020 Share Posted June 2, 2020 if i set up a wire loop J with a current I flowing clockwise, and attach wires AB, BC, CD & DG as seen in the picture the current on wires AB, BC, CD & DG i would expect to be 0.5I while the portion of loop J (portion AC and CG of wire loop J)adjacent to wires AB, BC, CD & DG also carries 0.5I my question: are the forces between the current in each wire and current loop J attractive to each other? and are the forces between the currents in the wires repulsive or attractive? Link to comment Share on other sites More sharing options...
swansont Posted June 2, 2020 Share Posted June 2, 2020 Why is this speculation? Link to comment Share on other sites More sharing options...
michel123456 Posted June 2, 2020 Share Posted June 2, 2020 (edited) 2 hours ago, swansont said: Why is this speculation? Maybe because Speculation is repulsive? Edited June 2, 2020 by michel123456 Link to comment Share on other sites More sharing options...
Strange Posted June 2, 2020 Share Posted June 2, 2020 18 hours ago, DandelionTheory said: the current on wires AB, BC, CD & DG i would expect to be 0.5I while the portion of loop J (portion AC and CG of wire loop J)adjacent to wires AB, BC, CD & DG also carries 0.5I That will only be true if you arrange for the resistance of ABC and the arc AC to be equal (e.g. make the wires AB and BC have ~1.4x greater cross-section) Link to comment Share on other sites More sharing options...
Ghideon Posted June 2, 2020 Share Posted June 2, 2020 (edited) 20 hours ago, DandelionTheory said: are the forces between the current in each wire and current loop J attractive to each other? and are the forces between the currents in the wires repulsive or attractive? I say the currents causes magnetic fields that creates attractive force between the cables. A few assumptions are made, listing them so others may spot flaws. First I assume the currents actually are able to flow the way you describe. Second I assume the currents' directions will be as in picture below; I've just added more arrows to your picture. Then I also assume the loop is large so that we can neglect attraction across the loop such as AB <-> DG. The above allows me to do an estimate without requiring the usage of the general case formula for Ampere's law*: Since currents are flowing roughly in the same direction in cables they attract. I do not have the time to try to apply the formula to check, so I boldly provide the answer from the reasoning regarding the geometry. Hopefully good enough for further discussions. *) General case: Edited June 2, 2020 by Ghideon Link to comment Share on other sites More sharing options...
joigus Posted June 2, 2020 Share Posted June 2, 2020 The r12 convention tends to confuse me. I'd go with applying twice the right-hand rule. One for field/source and a second one for Lorentz force law: \[\boldsymbol{B}_{1}\sim\boldsymbol{\nabla}\times\boldsymbol{j}_{2}\] \[\boldsymbol{F}_{1}\sim\boldsymbol{j}_{1}\times\boldsymbol{B}_{1}\] The force on j1 is towards j2. Resp. for 2 <-> 1 I assume with Ghideon that there aren't, e.g. power sources that invert the current along AC or CG along either wire. Neither do I see how this is a speculation. Link to comment Share on other sites More sharing options...
Strange Posted June 2, 2020 Share Posted June 2, 2020 7 hours ago, swansont said: Why is this speculation? ! Moderator Note Moved to Physics. Link to comment Share on other sites More sharing options...
DandelionTheory Posted June 4, 2020 Author Share Posted June 4, 2020 On 6/2/2020 at 7:53 AM, swansont said: Why is this speculation? "and are the forces between the currents in the wires repulsive or attractive?" my speculation. Link to comment Share on other sites More sharing options...
swansont Posted June 4, 2020 Share Posted June 4, 2020 2 minutes ago, DandelionTheory said: "and are the forces between the currents in the wires repulsive or attractive?" my speculation. No, that’s a question. Link to comment Share on other sites More sharing options...
Ghideon Posted June 4, 2020 Share Posted June 4, 2020 (edited) 59 minutes ago, DandelionTheory said: "and are the forces between the currents in the wires repulsive or attractive?" my speculation. Just to reduce the risk for any misunderstandings regarding my answer: There are no time dependencies; forces are constant. The forces are also cancelling each other. Edited June 4, 2020 by Ghideon grammar Link to comment Share on other sites More sharing options...
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