This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Pendule. Robert Ferrol fr Korrigan CommonsHelper Robert FERREOL fr Robert FERREOL original upload log page fr Pendule Robert FERREOL bytes no Ferrol Diagrams of pendulums Animated Animations of physics
Page 2023 Free-images.com. All images are Public Domain