1. Lorentz force

\[F_{\mathrm{Lorentz}} = q \left(\vec{E} + \vec{v} \times \vec{B} \right)\]

2. Homopolar electric motor

Motor homopolar neutral
Figure 1. Build your own motor [1]

WP: Homopolar motor

  • alkaline battery (AA works well)

  • permanent magnet(s)

  • bare wire

Same principle, opposite construction with rotating magnet: [2]

YouTube: ElectroBOOM - Super Simple DC Motor

1. From https://commons.wikimedia.org/wiki/File:Motor_homopolar_neutral.png
2. From https://commons.wikimedia.org/wiki/File:Homopolarmotor_MAQ03891_smial_wp.ogv