In this paper, we present a new technique to study the dynamics of a free-falling object in a lab
setting and to measure the acceleration due to gravity g using a simple and economic setup. The
precise measurement of time taken for an object to fall freely passing an infrared (IR) transceiver
is utilized to deduce the acceleration due to gravity. The reflected IR intensity from a
free-falling 0.19 m rod of equally spaced white stripes of 0.01 m is detected and sent to a digital
oscilloscope to observe and record the falling time period of each stripe. By fitting recorded
elapsed falling times to the well-known quadratic equation of motion under constant acceleration, an
accurate value of the acceleration due to gravity of g = 9.8092 ± 0.0384 m s −2 is obtained. In
addition to its accuracy, the proposed technique is safer and more economic than most of the other
currently used setups to determine g in undergraduate teaching labs. This study may provi…