Question: The famous horse & cart physics scenario is explained. This scenario is used to describe why many people have a common misconception about what Newton’s 3rd Law says & does not say. Use this scenario to describe how people try to argue that no object should move if Newton’s Third Law & Second Law were correct (i.e. if all forces have an equal & opposite force, then there would be no net force & if there is no net force then no objects should move). First write out the confused logic the horse uses. Second, write out the correct logic. Finally, explain the importance of external forces acting on a system (in this case the external forces acting on cart & horse).

1. What is the logic the horse uses?
2. What are the external forces acting on the horse & cart?
3. What is the horse stating incorrectly?