MadSci Network: Physics |
In a previous question, Dr. Jerrold Franklin stated that Static EM fields can exert no force (http://www.madsci.org/cgi- bin/circR?/posts/1102435169.Ph.r.html). The equation for force in a volume from "Introduction to Electrodynamics", Griffiths, 3rd ed. is written in terms of the surface integral of the Maxwell Stress Tensor + d/dt (Volume integral of Poynting vector). Clearly, in the static case, the 2nd term drops out, and F=SurfaceIntegral [Maxwell Stress Tensor]. This is a non-zero quantity in general, so in general, static fields can exert force. Doesn't this contradict the Dr. Franklin's previous answer?
Re: Static EM fields and momentum
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