Centre of mass of standard weights: another experiment with Lego and Tracker

• Published in: Physics education Vol. 59; no. 2; pp. 25014 - 25021
• Main Authors: Purata-Sifuentes, Omar-Jair, Echegoyén-Naranjo, Carlos-Augusto, Vargas-Torres, Carlos
• Format: Journal Article
• Language: English
• Published: Brecon IOP Publishing 01.03.2024
• Subjects: Center of mass; centre of mass; Cost analysis; Higher education institutions; Lego; Polynomials; Regression models; standard weights; Tracker
• ISSN: 0031-9120; 1361-6552
• DOI: 10.1088/1361-6552/ad1f01

Abstract Determine the centre of mass (CM) of standard weights is needed when two weights with different heights are compared. However, reproducing related experiments is difficult for high school or higher education institutions with non-expensive instrumentation or low budgets to construct specialised devices. This work addresses that problem in a two-way approach: dynamic video-based analysis and making a low-cost static device with Lego bricks. Published scientific papers support both methods. The experimental results of the video-based procedure were used to fit a polynomial regression model to find the CM location. On the other hand, the Lego device approach gives the ubication of the CM directly. Both methods were compared against geometric formulae publicly available to locate the CM of standard weights. The whole three stages project could be used in a senior high school or undergraduate physics course to teach about the comparison and compatibility of methods in experimental physics.