Alternative conceptions in Galilean relativity: inertial and non‐inertial observers

This concluding part of a study on Galilean relativity focuses on students’ notions with regard to the inertial and non‐inertial character of frames of reference. (See Panse et al. 1994, Ramadas et al. 1996). The results show that students: adopt kinematic criteria for deciding the inertial or non‐inertial character of frames; consider this character to be a ‘relative’ property of two frames rather than an intrinsic property of a given frame; and equate pseudo‐forces to ‘imaginary’ forces. Centrifugal force is associated with rotating objects rather than with rotating frames; the latter are localized by the finite extension of their associated objects. Anthropomorphic criteria are invoked to judge the existence of centrifugal force, which is regarded as a reaction (in the sense of Newton's third law) to the centripetal force on a rotating object.