Pixel International Conferences

The teaching of physics is a very important social task even if it concerns only basic physics. The case of a real trial in which a bad knowledge of physics laws led a monocratic judge to issue a judgment based on erroneous physical conclusions is reported. The relevant thing is that the monocratic judge was misled by a technical report prepared by an alleged expert. The technical report should have described the motion of a rubble detached from a building and that, after hitting a ledge, would hit a person at a certain horizontal distance. However, the technical report contains no equation and no calculation of possible trajectories, while it describes the problem through conceptually incorrect basic physics considerations. The conceptual errors contained in the technical report concern the relationship between forces and motion, the concepts of energy, momentum, action-reaction pair (third-law pair), couple of forces and collision dynamics. In addition, the technical report contains serious methodological deficiencies. The analysis of the technical report and the conceptual errors it contains will be conducted: it can be a useful help for physics teachers to identify some physics concepts that could be misunderstood by students and that should be explored in depth. In addition, the conducted analysis could be a useful and interesting tool for students of basic physics courses so that they can appreciate even more the real importance of what they study and can better understand the principles of basic physics.

Keywords: projectile motion, Momentum-Impulse theorem, Physics teaching, Restitution Coefficients, Action-Reaction.