In this clip, the students are discussing a problem with the professor in a whiteboard circle. Throughout the clip, the professor is referring to one group’s work, which took place before the clip began. The professor wants to point out what the group did correctly. The professor, with participation from the class, determines that the group first made a system schema, then made a diagram, and then made a force diagram. Next, the professor explains, the group broke the forces up into components, and then chose a frame of reference. At the end of the clip, the professor points out that the group did all of these things so that they would be able to use Newton’s Second Law, and from there they would be able to solve the problem.
This clip takes place in week 12 (Practicing with Forces & Exam). The problem that the professor is referring to is problem number 2 from the “Possible Force Problems” activity worksheet.