Animation vs. Physics by Alan Becker is truly a masterpiece. However, I think some of the scene is inacurate. Especially about conservation of momentum and magnetic slingshot.

Please feel free to correct me if I'm wrong. I really like Animation vs Physics, but I found this part is a bit confuse me, so I make this video in hope that someone can help me to clarify that.

All credits to Alan Becker.
Original video:    • Animation vs. Physics  
Music: Animation vs. Math    • Animation vs. Math