So was her example wrong, or just poorly chosen? Because the way she made it seem was that some unknown force we haven't learned yet is being exerted by the wall.
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...