21: The Ponderomotive Force Last updated Dec 30, 2020 Save as PDF 20.3: Example- Pendulum Driven at near Double the Natural Frequency 21.1: Introduction to the Ponderomotive Force Page ID30174 Michael FowlerUniversity of Virginia ( \newcommand{\kernel}{\mathrm{null}\,}\) 21.1: Introduction to the Ponderomotive Force21.2: Finding the Effective Potential Generated by the Oscillating Force21.3: Stability of a Pendulum with a Rapidly Oscillating Vertical Driving Force21.4: Hand-Waving Explanation of the Ponderomotive Force21.5: Pendulum with Top Point Oscillating Rapidly in a Horizontal Direction