1. The problem statement, all variables and given/known data Hi everyone. I am a grade 11 physics teacher. This week, I will be teaching about Newton's first law in class. I'm having trouble explaining one thing. Students generally understand that a hockey puck moving on ice will continue to move with constant velocity. In this case, there is a complete absence of force. However, when there are balanced forces, students don't get it. For example, in an elevator moving with constant speed, the force due to gravity and the tension on the elevator are balanced. 2. Relevant equations 3. The attempt at a solution Typically, I tell students that if the gravity force were bigger than the tension force, the elevator would accelerate down. And if the tension force were bigger, the elevator would accelerate up. However, this doesn't seem to rectify the misunderstanding. Does anyone have a better way of explaining this? Thanks in advance!