In this clip, the students are gathered around in a whiteboard circle while the professor is standing in the middle with a whiteboard of his own. The professor is explaining a problem that has 4 unknowns and 2 equations. He notes that the rule is that you need one equation for each unknown in order to solve for each unknown. The professor points out one group that took several steps to reduce the number of unknowns and added equations to solve it. The professor explains that setting up the problem by doing the system schemas, making force diagrams, etc, is doing the bulk of the work—the physics. This, he explains, is the most important part of the problem, and that everything after that is just using math. The professor explains that the focus is to understand the physics.

This clip takes place in week 10 (Investigating Frictional Forces). This discussion takes place after students have worked on the “Investigating Frictional Forces” lab.