I understand that a weight held up by a weightless string causes tension (T) in the string. And it makes perfect sense that T = mg when the string is perfectly vertical. It is well known that once the string is put at an angle, T = mg/cosθ, but this makes no sense to me at all. How can we get more force out of mg than mg itself? It's almost like force is not conserved here, which I don't even know if has to be. I think that a possible solution is that there is a horizontal normal force holding the string to keep the string at an angle. But, this force seems to only exist because of the mg, so how can mg ≤ mg/cosθ?