Door Hinges

[Oliver]

I have noticed that some doors have 3 hinges arranged in a certain way, one near the bottom, one near the top and then one not far away from the top hinge. So basically, 2 near the top and one near the bottom. Anyone know why this is?

[BadBob]

Gravity, the center point of the balance and its effects on the weight of the door. I don't know anything about physics so somebody might be able to give a proper answer. Take a heavy book and lean it against your finger, with you finger at the top, if you drag your finger down the amount of resistance needed to keep the book up becomes greater, by having the third hinge higher its supporting the top, where most of the force pulling it down is located.

[BobbyLove01]

that is true. being a carpenter when i hang fire doors or solid doors i will always put 3 hinges on the door because of the weight factor.