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Is this effect common in all fields of physics?

  1. May 29, 2012 #1

    I was wondering in a physical action/reaction the subatomic particles or even the large object would usually avoid the significant resistance and take a easier route out is that true? like in energy conservation, matter to energy conversion, electric current, magnetic fields, subatomic particles colliding, force on objects to move,etc... And many more all those little physical objects and events that surround us every single second of the day. When there are countless options would they take the easier route which has the lessened resistance... lol this might sound funny but seriously try to imagine what I mean and give me you're opinion! This thought is stuck in my mind I just want to answer that enormous curiosity in my head!

    Finally forgive me if I gave you some foolish named physical reactions I didn't really know how to put it lol...

    Last edited: May 29, 2012
  2. jcsd
  3. May 29, 2012 #2
    I've noticed the pattern you are explaining too. I think in some examples, they do have an underlying principle, and others maybe not.

    Two underlying principles I can think of are the 3rd law of thermodynamics, which says a system's energy state tries to approach a minimum equilibrium. I can't say with authority, but I think a lot of the "path of lease resistance" behavior is related to this.

    Another is fermat's principle, which is used in classical mechanics and also optics/ray tracing and relativity. Basically this principle says that a ray of light will travel the shortest distance available. I don't know enough about it, but I have always been confused about its physical reality.. as in is it an actual physical property or is it just using a mathematical construct that explains the physical phenomena.

    I'm not saying these two principles are related to each other, but I have seen how they have been used to explain some of the examples you gave.
  4. May 29, 2012 #3
    I'm thinking that the principal of least action may be behind some of your observations.
  5. May 29, 2012 #4
    So is it safe to say in most physical systems when there are to paths one with higher resistance(of any kind) and another path which basically avoids the resistance or the most difficult one and goes for the easier path and that due to the least action principle?

    I do believe a system will try to reach to a balance from all the applied energy, force, etc... At the same time I think it will go for the easier method to achieve it if there is one.
  6. May 29, 2012 #5
    I think you mean the 2nd law.
  7. May 29, 2012 #6
    You're right, thanks for correcting me, I did mean the 2nd law haha.
  8. May 29, 2012 #7
    You are kind of talking in too general terms to get a good answer to your question. The words easier, your use of resistance, and path are all subjective and depends on the context you're talking about. I think you can't jump to a conclusion that every phenomena in physics is related/resulting of the least action principle when you talk so generally.
    Last edited: May 29, 2012
  9. May 29, 2012 #8
    The principal of least action appears in various forms in many modern theories, but it is not necessarily as simple as a particle always taking the path of least action. For example in QED we sum the action of all possible paths to a given destination to determine the probability (amplitude) that the particle will go to that location. The path of least action ends up being the most probable path, but not necessarily the path that a given particle takes.
    Consider the double slit experiment, if every photon took path of least action, we would not see the interference pattern on the screen.
    Last edited: May 29, 2012
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