학술논문

Digital video analysis of falling objects in air and liquid using Tracker
Document Type
article
Source
Revista Brasileira de Ensino de Física. March 2013 35(1)
Subject
digital camera
video analysis
falling
drag force
Tracker
Language
English
ISSN
1806-1117
Abstract
Motions of falling objects through air and liquid media were captured by a conventional digital camera and analyzed by a video analysis open source called Tracker. The position of the moving objects at every 33 ms was evaluated from series of images and the velocity was averaged from the change in position during each interval. For the falling in air experiment, the displacement of a ball was proportional to the time squared and the agreement with the theory was indicated by the derivation of the acceleration due to the gravity with an acceptable level of accuracy. In additions, the effects of the height of falling, the camera distance as well as the color of ball and background were investigated. In the case of falling in glycerol, the average velocity of a metal bead was initially increased with the time of falling until reaching a constant value of the terminal velocity.