This worksheet is intented to explore the motion of a charged particle in an electric field and a perpendicular magnetic field. [br]Due to the complexity of the calculations it's highly advisable to download the ".ggb" file and run it on a desktop with the classic version of Geogebra (Geogebra5).[br]The remarkable characteristics of the resulting motion (when both fields are present) is that the trajectory is a trochoid.[br]Further details on the math behind the construction are in the pdf. Others will be added (hopefully) soon, maybe in [url=https://www.lucamoroni.it]www.lucamoroni.it[/url].[br]I'm also planning a major extension with a variable [i]E[/i] field (with wonders and special effects!)