CENTRIPETAL AND/OR CENTRIFUGAL

The author considers at length the array of contradictory answers provided by university students when examined on the rotation of rigid bodies in classical mechanics during their undergraduate courses. The rotation of a body can be explained simply both in terms of kinematics and dynamics, yet this is often complicated by the various definitions formulated by different authors. As a result some students are uncertain whether a person sitting on a merry-go-round is acted on by centripetal or centrifugal force; some students even consider that centrifugal acceleration (which is actually non-existent) is the reason for the existence of centrifugal force. The author intends to show that the students’ misunderstanding arises from two different sources: in the available literature, different forces are called by the same terms and, secondly, different terms are used to name identical forces. This Babylonian confusion of tongues has a long tradition, stretching back to Newton’s Principia. This paper tries to distinguish and compare different definitions, formulations and Terminology related to the rotation of rigid bodies. By discussing a few worked-out examples in detail the author hopes that any existing misunderstandings might be clarified.