In this clip, students are gathered around in a whiteboard circle. One student claims that all forces are M’s times A’s. The professor asks the students if the mass-less rope is accelerating, and then leads the students to the conclusion that the sum of the forces, or the net force, is what’s equal to M times A.

This clip takes place during week 9 (Investigating Forces Part2). The students are discussing their work from the “Newton’s Second Law Variations on a Theme” activity worksheet.