A Didactic Note for Laboratory Determination of Local Acceleration of Gravity

Abstract

We describe a laboratory experiment in which the local acceleration of gravity, g, was determined. This work is primarily one utility of a theory for conversion of mechanical energy into electrical energy. It involves measurement of impact time between two metallic bodies. The setup consists of a thin copper wire suspending a pendulum metal bob. The wire was passed over into connection with a chosen resistor in series with an electrolytic capacitor. The latter connected to a larger metallic body. At a determined height, the bob was allowed to make an impact with the larger metallic body to induce an electric current of which voltage was recorded by means of a voltmeter connected across the electrolytic capacitor. Errors due to oscillations in the conventional pendulum experiment were avoided because only one impact was allowed for every set of readings. Interesting common analyses were found sufficient for calculations of standard errors on g.

Keywords: Didactic, local acceleration of gravity, conversion of mechanical energy, collision time, capacitor, pendulum bob, impact time, error calculation

PACS: 01.40.-d, 01.50.Pa, 01.40.J-, 01.40.gb, 01.30.lb