Yes I would like an answer to thins question...
Why do you think doorknobs are located where they are on a door?
I believe it has to do with being more efficient because on the law of angular momentum. Any thoughts?
-asian_al
2006-12-01 11:41:50 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The knob is opposite the hinges to maximize the torque produced by your hand around the door's axis of rotation.
2006-12-01 11:46:54 · answer #1 · answered by Robert A 2 · 0⤊ 0⤋
It is not in the optimum place to maximize the torque about it's axis of rotation. If it were it would be one the absolute edge of the door. Since it is not, some torque is lost due to the decrease in the moment arm length. But this decrease in length is for durability and security. By placing the know a small distance from the edge it makes the door harder to kick in due to the extra wood/metal/whatever around the doorknob. It also allows the securing mechanism, the little rod in the door (not sure what it's called), to be contained in the door.
If this is a question from a physics textbook then the answer they are probably looking for is "to maximize the force" or something like that.
2006-12-01 20:09:32 · answer #2 · answered by thegreatdilberto 2 · 0⤊ 0⤋
Where ever is the position of the knob, to open a door a minimum torque of F x R is necessary to balance the frictional torque at the hinges.
Longer is the R, lesser is the force F. Therefore even kids can open a door by applying a less force, if R is large. But the same amount of work has to be spent, whether it is a kid or man.
Thus fixing the position of knob is a matter of convenience and no amount of work is saved.
In windows the knob is provided only near to the hinge. If the knob is at the farther end one has to extend his arm to pull the window door (in the case of a window door opening outside the wall).
About knob and latches, there are doors with separate latches and knobs. Further latches are provided on the farther end from the hinges, because a greater force is necessary to open the door when the door is latched.
One can provide the latches near the hinge side also. And the door will be still locked. But one can open the door easily with a less force applied at the farther end.
Thus the position of knob is a matter of convenience only.
2006-12-02 00:19:54 · answer #3 · answered by Pearlsawme 7 · 0⤊ 0⤋
Door-knobs are placed at half-inch below the "average height" of the pocket on commercially manufacturer trousers, in order to maximize the probability the trousers will be ripped by getting caught on the doorknob. The International Trouser Pocket Manufacturer's Associaion (ITPMA) actually pay qiute a large amount of money to the Door Knob Placement Advisory Council (DKPAC) to ensure this arrangement, since it boost trouser sales.
2006-12-01 19:51:12 · answer #4 · answered by Anonymous · 0⤊ 0⤋
All the above are very creative but overlook the obvious: A knob, to be practical at all, has to be located at or near the the latch it controls. By definition, the latch is located on the side opposite the hinge.
2006-12-01 22:05:30 · answer #5 · answered by Steve 7 · 0⤊ 0⤋
Maybe, or the easily reachable place for a majority of human beings.
2006-12-01 19:47:33 · answer #6 · answered by Modus Operandi 6 · 0⤊ 0⤋