This clip involves students gathered around in a whiteboard circle. The discussion is regarding the energy diagram of a book sliding across a table. One student explains her group’s work and how they decided to include gravitational potential energy in their diagrams even though it was constant. The professor asks the class if the student’s explanation is correct. The discussion leads to the professor pointing out that both instances are correct—including gravitational potential energy or not, since it’s constant. The professor states that if the book were falling off the table, for example, then gravitational potential energy would need to be included. The professor ends by admitting that he had asked the one group to erase their gravitational potential energy diagram to spark the discussion.
This clip takes place during week 5 (Predicting 2D Motion & Energy). The students are discussion problem #2 from the “Energy Pie Charts” activity worksheet.