This clip involves a discussion between the professor and a group of (at least) 5 students who are working on problems at their desk. The discussion is regarding position versus time graphs—namely, that an initial position of the object must be assumed. The discussion also includes the fact that the position versus time graph can be shifted depending on the initial position chosen.
This clip takes place in week 3 (Becoming Quantitative with Constant Acceleration). The problems that the students are working on are from the Becoming Quantitative worksheet. The goal of these problems is to create quantitatively accurate position versus time graphs.