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Thread: nonconservative forces

  1. #1 nonconservative forces 
    Forum Ph.D. Heinsbergrelatz's Avatar
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    can anyone explain the term nonconservative forces with perhaps an example??

    thank you


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  3. #2  
    Moderator Moderator Dishmaster's Avatar
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    A conservative force obeys the the conservation laws (energy, momentum, etc.). non-conservative forces don't do this, if viewed from a macroscopic perspective. One example is friction. Friction can be regarded as an effective force that works in the opposite direction of the acceleration or movement. Since there is no macroscopic counter-movement, the conservation of momentum seems to be violated. But instead, the energy (e.g. kinetic) is transformed into heat, which basically is the microscopic movement of atoms.


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  4. #3  
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    Momentum is always conserved. However, energy may be lost to heat.
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  5. #4 Re: nonconservative forces 
    . DrRocket's Avatar
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    Quote Originally Posted by Heinsbergrelatz
    can anyone explain the term nonconservative forces with perhaps an example??

    thank you
    dishmaster is correct.

    A conservative force field is one in which the line integral around any closed curve is zero -- so that the net work in going from and back to any fixed point is zero.

    There are some non-conservative force fields. Time-varying electromagnetic fields are one example, and that is why they can induce an electromotive force around the turns in a coil, which is how electric generators work.

    A defining characteristic of a conservative field is that it is the gradient of some scalar, and that scalar is the potential. Electrostatic fields arise from a potential (voltage differences) and therefor are conserevative, while time-varying fields do not.
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  6. #5  
    Forum Ph.D. Heinsbergrelatz's Avatar
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    Thank you for the help :-D
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