Video analysis of the fall and vertical downward launch of Styrofoam balls with air drag

The drag effect on a falling ball caused by air is a conventional subject in the most well-known textbooks of classical mechanics and fluid dynamics. Further, there are some papers that employ video analysis to track objects movements in the air making it possible to obtain position data as a functi...

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Bibliographic Details
Published in:Physics education 2021-07, Vol.56 (4), p.45005
Main Authors: de Oliveira, A L, de Jesus, V L B, Sasaki, D G G
Format: Article
Language:English
Subjects:
air resistance
Classical mechanics
Concept Formation
Debugging
drag coefficient
Drag coefficients
Equations (Mathematics)
fall and vertical launch
Fluid dynamics
Fluid flow
Graphs
Handheld Devices
Motion
Physics
physics teaching
Reynolds number
Science Experiments
Science Instruction
Scientific Concepts
Software engineering
Styrofoam
Technology Uses in Education
Telecommunications
Textbooks
video analysis
Video Technology
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Summary:The drag effect on a falling ball caused by air is a conventional subject in the most well-known textbooks of classical mechanics and fluid dynamics. Further, there are some papers that employ video analysis to track objects movements in the air making it possible to obtain position data as a function of time and its graphs. However, none of them addresses the case of a ball thrown downwards, maybe because this situation is neglected by textbooks or probably due to the experimental difficulty to perform this kind of launch manually. In this paper, both the fall and the vertical launch down of five different Styrofoam balls are filmed with an ordinary smartphone camera and analysed by using the free software Tracker. The position and velocities graphs depicted clearly the air drag effect on the ball's movements. The entire raw data are compared with a theoretical model and therefore terminal and initial velocities can be extracted as adjusted parameters from simple mathematical fits. The Reynolds number and the drag coefficient calculated for each ball agree with those found in the literature.
ISSN:0031-9120
1361-6552
DOI:10.1088/1361-6552/abf1d2