In this clip, a group of students (at least 4) are gathered at their desk, working on problems. The professor approaches the table and becomes involved in a discussion with the group. Namely, the discussion involved the direction of the acceleration, and how it will take on either a positive or negative value depending on how you set your coordinates.
This clip is from week 3 (Becoming Quantitative with Constant Acceleration). The work that is being discussed is from problems 3 and 4 from the “Specific Models Using Constant a” worksheet.