Paul - UWEC
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Paul Thomas Professor, Department of Physics & Astronomy AMERICAN JOURNAL of PHYSICS Volume 82, No. 8, August 2014 A PUBLICATION OF THE AMERICAN ASSOCIATION OF PHYSICS TEACHERS Available online—visit http://aapt.org/ajp Poynting's theorem states that the rate at which work is done on the electrical charges within a volume is equal to the decrease in energy stored in the electric and magnetic fields, minus the energy that flowed out through the surface bounding the volume. Most familiar applications of Poynting's theorem concern stationary currents or circuit elements. We apply Poynting's theorem to the homopolar generator, a disk-shaped conductor moving in a background magnetic field. This allows us to show that the phenomenon of magnetic breaking arises as a natural consequence of Poynting's theorem. Energy Conservation and Poynting's Theorem in the Homopolar Generator Co-authored by: Christopher Chyba, Department of Astrophysics and Woodrow Wilson School of Public and International Affairs, Princeton University and Kevin Hand, Jet Propulsion Laboratory American Journal of Physics
Transcript of Paul - UWEC
Paul Thomas
Professor,Department of
Physics & Astronomy
AMERICANJOURNAL
of PHYSICSVolume 82, No. 8, August 2014
A PUBLICATION OF THE AMERICAN ASSOCIATION OF PHYSICS TEACHERS
Available online—visit http://aapt.org/ajp
Poynting's theorem states that the rate at which work is done on the electrical charges within a volume is equal to the decrease in energy stored in the electric and magnetic fields, minus the energy that flowed out through the surface bounding the volume. Most familiar applications of Poynting's theorem concern stationary currents or circuit elements. We apply Poynting's theorem to the homopolar generator, a disk-shaped conductor moving in a background magnetic field. This allows us to show that the phenomenon of magnetic breaking arises as a natural consequence of Poynting's theorem.
Energy Conservation and Poynting'sTheorem in the Homopolar Generator
Co-authored by: Christopher Chyba, Department of Astrophysics and Woodrow Wilson School of Public and International Affairs, Princeton University
and Kevin Hand, Jet Propulsion Laboratory
American Journal of Physics
