My teacher just explained to us Newton's Third Law, and one example she used was her pushing against a wall. She stated that the net force would equal zero because the wall was pushing back, but that doesn't make sense to me... What I was thinking was that the force of her pushing was weaker than the tension in the wall, therefore she couldn't push through/break/whatever. But if it was tension rather than some force pushing back, that would mean the net force wouldn't equal zero, right? Because the tension isn't going to equal exactly the force of her pushing. It would have to be as great as the maximum force needed to break it, which is more than how much she is pushing. I'm confused I guess.