English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In a recent Letter [arXiv:1205.0096], Mansuripur considers a magnetic dipolepositioned at a fixed location from a point charge. Performing a Lorentztransformation to a laboratory frame where the charge distribution moves hefinds that `a net torque acts on the dipole pair'. He then argues that `thistorque in the (lab) frame in the absence of a corresponding torque in the(rest) frame is sufficient proof of the inadequacy of the Lorentz (force) law'.  In this comment we demonstrate that the presence of a torque is notincompatible with special relativity: it is required by the conservation lawsthat apply to the total momentum of the system (including the particles). Wefurthermore stress that classical electrodynamics needs a consistent dynamicaldescription of the particles that involves coupled equations for theelectromagnetic fields and the trajectories [M. Brachet and E. Tirapegui, NuovoCimento Soc. Ital. Fis. A 47, 210 (1978)] and any conserved quantity will thencontain contributions from both the field and the particles.

Comment on "Trouble with the Lorentz Law of Force: Incompatibility with Special Relativity and Momentum Conservation"