|Re: Rubber feet on 35s and general 1st impressions|
Message #39 Posted by Vincze on 8 Aug 2007, 11:37 a.m.,
in response to message #35 by Thomas Radtke
Okay.. although I am not native American, let me Let me try this again today when my mind is clear and not so tired and full of wine.
A three legged dog walks into bar... no wait. Wrong explanation.
Okay, I try again. A three legged stool or table will not wobble because the end of legs always form a plane. It that simple, but I know this a sophisticated group who not accept simple "Hungarian Method", (as Walter so nicely state this is) as answer.
To look at this mathematically, a three legged stool or table solves for a system of three equation in three variable, while a four leg table will change mind about which three of four equation to solve for the same three variable.
Pretend there a three legged stool or table sitting on three legs. Now add a fourth leg on some line out from the top of the stool to the floor. There is only one single length which will now just reach the floor. If the fourth leg is a little too short, then the leg will not contact, and the stool will pivot about two of the legs (wobble), or as in mathematical equation, it will change it's mind about which three of four equations to solve for. Also, if one leg a little to long, or floor is uneven, then when fourth leg come in contact with ground the stool will have to lift one of the other three legs off the floor making stool wobble.
Now let say that you have stool that had four *exactly* equal legs forming a square on the bottom of the stool, but now the floor is uneven. Now, there will be some way you should be able to adjust stool so that all legs (4) touch the ground and there will be no wobble. This like intermediate value theorem.
Now, one thing we also have to remember is that three legged stool not always very stable. So how do we offset this. One way is to extend out legs so that it very hard to tip over. Or, as HP do, they make one leg (rubber foot pad) very wide, and others small. This will prevent instability, except in most severe situation with sever angles, in which case, legs (or rubber feet) need to be longer (taller) respectively. That look funny on calculator though.
I hope that make sense, if not, I give up. :)
Edited: 8 Aug 2007, 12:43 p.m.