Experimental study of determination of earth’s gravitational acceleration using the concept of free-fall motion and conservation of mechanical energy

Abstract

Measurements of gravitational acceleration in this study use the concepts of free-fall motion and mechanical energy conservation. The purpose of this study is to compare the values of gravitational acceleration obtained from the two experiments and to determine the factors that cause deviations from the measurements of the gravitational acceleration value from free-fall motion experiments and the law of mechanical energy conservation. The research method used was a descriptive analysis of primary data in the Applied Physics Laboratory of Politeknik Negeri Bandung. The data was collected using free-fall motion equipment and the law of mechanical energy conservation. Height is the independent variable, and time is the dependent variable. The data were processed using a computer-aided device, and it is obtained the g value with the concept of free-fall and mechanical energy conservation by 9.54 m/s2 and 10.1 m/s2. The deviation of g value in the free-fall motion is caused by the presence of magnetic remanence that holds the ball from falling immediately when the time calculator was operated. The t result, which is too large, causes the value of g becomes too small. The result of g deviation in mechanical energy conservation is obtained by determining the location of the light source when the ball is in a stable condition. Meanwhile, in the real measurement, the ball moves as it passes through the light sensor, which results in a large tension force so that the sensor position moves in a higher state. The result is Δt becomes smaller than the real one so that v becomes too large. As a consequence, the value of g becomes too large.