J. Vila; C. J. Sierra
Description:
Earth force and weight force are two of the magnitudes that are most used in mechanics and in our daily life. These twoterms are commonly confused or taken as the same and this may lead to erroneous conclusions, as for example inrelation to weightlessness. The following paper is a didactic approach that explains these concepts with great precisionon the basis of their respective interaction and the three laws of Newton in relation to mechanical movement. It has beenused with teachers and with groups of students, and very good results has been obtained.