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Faster than g, an experiment for the classroom
Authors: Roque, R.; Pedro S. P. Silva; Silva, MR
Ref.: Phys. Educ. 60(4), 045022 (2025)
Abstract: This paper presents a quick-to-assemble experiment demonstrating the faster than g phenomenon where the tip of a falling hinged rod accelerates faster than gravity, g. Designed for upper-secondary and undergraduate STEM students, the experiment uses readily accessible materials, including a smartphone, to investigate through video-analysis the rotational dynamics of the rod. Students can observe and measure angular and linear positions and even calculate their numerical derivatives, with a spreadsheet, with enough precision to study energy conservation. The results challenge common notions about rotational dynamics leading to a deep understanding of torque, rotational motion, and rotational energy, offering consistent experimental values for g, and time and angular dependences that align closely with theoretical predictions.
