Demonstration of the parallel axis theorem through a smartphone

Abstract

New learning strategies try to extend the use of common devices among students in physics lab practices. In particular, there is a recent trend to explore the possibilities of using smartphone sensors to describe physics phenomena. On the other hand, the study of the moment of inertia by the use of the torsion pendulum is a typical example in the first courses of fundamentals of physics. This example allows the exploration of harmonic motion, Newton’s second law, the moment of inertia theory, and the parallel axis theorem all in one. Here, we report the use of the accelerometer sensor of a smartphone to visualize and demonstrate the parallel axis theorem in a torsion pendulum.

Un laboratorio de ciencias en tu bolsillo

“…En un trabajo posterior, unimos la deslizadera mediante un resorte a un motor vibrador, lo que también nos permitió caracterizar oscilaciones forzadas (Salinas, 2018a). También con el acelerómetro se pueden caracterizar oscilaciones acopladas (Castro-Palacio, 2013b), batido mecánico (Giménez, 2017a), movimientos circulares Salinas, 2019), oscilaciones bidimensionales (Tuset-Sanchis, 2015; Giménez, 2017b), etc. El giroscopio del smartphone (también conocido como sensor de velocidad angular) permite analizar la dinámica del movimiento de un yoyó (Salinas, 2020) (Fig.…”

Experimental analysis of a compound pendulum with variable suspension point

“…In the current study, small oscillations of a compound pendulum are analysed using different modern technologies [1][2][3][4]. The period of oscillation is measured as a function of its point of suspension, which affects its moment of inertia.…”

“…In the experiment proposed here, the period of the small oscillations of a physical pendulum whose point of suspension, and then, its inertia moment can be controlled is experimentally analyzed using different modern technologies [1,2,3,4]. As it involves key concepts in classical mechanics and can be readily implemented virtually in any Physics laboratory, the present experiment could encourage students' interest and motivation to experiment by themselves.…”

Inertia property determination by spectrum analysis of damped oscillation detection signal

“…One measured cylindrical part of 19.8365 kg is placed on the adaptor, which is 499.776 mm away from the centre of the torsion pendulum, and the other measured cylindrical part is placed on the adaptor, which is 499.830 mm away from the centre of the torsion pendulum. Then, according to the parallel axis theorem [37], the MoI of the measured loads should be 41.0543 kg·m 2 . This value can be regarded as the conventional true value of the measured MoI.…”