We have examined the understanding of students and physics teachers regarding Galileo’s law of free fall. Refining this law for an observer on the ground, which is usually neglected in textbooks, results in the acceleration of free fall being mass dependent. We found that physics students and high school teachers are unaware of the conditions for which Galileo’s law is valid, and the law is often identified with the equivalence principle.

Topics
General relativity, Newtonian mechanics, Newtonian dynamics, Two-body problem, Classical mechanics, Gravitational interactions, Education, Teaching, Interviews, Corrections
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The students volunteered to participate in the research performed in the same institution. This group was highly heterogeneous, including physics majors and students of different levels of training (B.Sc., M.Sc., and Ph.D.) and exposed to different lecturers.

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All the quotes in this paper were translated from Hebrew and thus may lose the colloquial character of the original.

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© 2009 American Association of Physics Teachers.
2009
American Association of Physics Teachers
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