Gravimetric analysis using smartphones and improvements in the equations of the simple pendulum experiment as a subterfuge for teaching Classical Physics

Contemporary gravimetry uses gravimeters to find the magnitude of gravitational acceleration (g) in a punctual manner on the Earth’s surface. This work considered the relevance of determining g in the didactic laboratory using the pendulum, making a careful analysis of the phenomena that affect the oscillating device, bringing contributions to the teaching of Classical Physics. The first, although modest, is effective, and proposes measuring the oscillation period using two smartphones. The second, a theoretical analysis of the effect of angular amplitude correlated to drag, on the period of pendulum oscillation. The third refers to the validation of two equations that provide the value of g like a function of latitude and altitude, with gravimetric data available on the IBGE website. At the Londrina campus of UTFPR, independent tests were carried out, allowing the value $g_{UTFPR-Ld}=(9.7873\pm 0.0012)m\cdot s^{-2}$ to be obtained. To validate the methodology and verify its accuracy, the two equations that provide g as a function of altitude and latitude were compared with gravimetric data to define which would be most suitable for generating the reference value. This done, it was found that the experimentally obtained value differed by $0.001m\cdot s^{-2}$ (0.01%).

Keywords:
Gravimetry; pendulum; smartphone; Physics teaching