The bottle flip challenge demystified: Where is the centre of mass?

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Carvalho, PS (Author) FCUP; Rodrigues, MJ (Author) Other

Journal

Title: Physics Education

Vol. 52

ISSN: 0031-9120

Publisher: Institute of Physics Publishing

Indexing

Scopus - 1 Citation

Scientific classification

CORDIS: Physical sciences > Physics

FOS: Social sciences > Educational sciences

Other information

Authenticus ID: P-00N-52V

DOI: 10.1088/1361-6552/aa70d7

Abstract (EN): Bodies can have very weird trajectories when tossed into the air. The amazing motion of a water bottle flip is qualitatively described as related to the position of the centre of mass (CM) with respect to the body's frame of reference. Although this is rather easy to guess from simple observations, it is not so obvious to verify quantitatively with the naked eye. In this work, we use video analysis and a computational model to show that the position of the CM changes in the frame of reference of the bottle, while it describes a parabolic trajectory in the frame of reference of the laboratory. We also show that the behaviour of the CM also explains the weird motion of the bottle. It can be observed graphically and discussed in the classroom with students, as it only needs some critical thinking and practically no math. © 2017 IOP Publishing Ltd.

Language: English

Type (Professor's evaluation): Scientific