In this clip, the students are gathered around in a whiteboard circle. The discussion is regarding a tennis ball hitting a racquet. The professor points out that modeling this scenario using constant acceleration doesn’t work because the strings of the racquet act like rubber bands, which provide a spring-type force. The professor notes that it is ok to model the force applied by the strings as being constant. The professor then plots the force as a function of time and the class says that the area can be found, and they provide the steps to do so. The professor then explains how the units of the area under the curve are the same units of momentum.
This clip takes place in week 12 (Practicing with Forces & Exam). The problem being discussed is number 3 from the “More Momentum Questions” activity worksheet.