93 replies to this topic

[colorclown26]

admins answer is probably the best, but why couldnt the builder just connect two of the bridges.

[someguy101]

You could just set up a village around the castle. Eventually the people in the castle will have to come out. They're going to need to come out for fresh water within a week easy.

[unreality]

or you could have someone hold down the first, say, 3 meters on the ground to suport the 6.5 meters hanging out over the moat. Then there would only be 3.5 meters (about 10 feet) to longjump, easily. And if someone couldnt, they could just bounce on the board because it would be springy, and then their jump would be much more powerful anyway. Easy.

Of course I like the corner idea too

[Ploper]

Well, do the edges of the moat have to be sheer edges?
If there is a slight slant in the edges of the moat, then by shoving the bridge into it couldn't they cross?

Or how about using catapults?

[wrzesinski]

Could you not also lash 2 footbridges together with a slight overlap to make one longer one?

But then the integrity of the footbridge would be compromised and nobody could guarantee your safety.

Haven't you read Stephen King's "Eye of the Dragon" and the "tension breaking point" theory?

who cares about safety they are conquerors not defenders...and who cant tie two bridges together with 4 feet overlap and not make it safe?

[Naruki]

Well, after reading the responses, I think the question can close some of the loopholes by a little rephrasing.

Some kids were wandering in the hills when they came across a square medieval castle on a square island. 1 meter from the edge of the walls was a moat - 10 metres wide - filled with foul-smelling water.

(Naturally, the moat has square corners, and the distance from an outer corner to its inner corner is about 14.1 metres wide.)

They found a couple of 9.5 metre planks, but otherwise had no tools to cross the moat. Nevertheless, they figured out a way across. What do you think they did?

[wukupdemon]

for those of you who suggested putting 1 unit of bridge diagonally across the bridge and then placing the other 8.5 unit length to complete the bridge on the corner have forgotten a simple process of calculation. Pythagorean therum suggests that the corner that we now are attempting to cross is no longer 10 units of length, but 14.1 units of length. and the diagonal idea only acconts for 0.866 unites of length, therefore, there is still 13.23 units of lenth to cover... and guess what, technology has not been updated... they can still only build 9.5M bridges, and i think the question asks us to assume that they only brought enough wood and nails for one bridge

silly them

[Slick_Rick9009]

First, about the post above mine, I don't know if I'm overlooking something, but why do you say 8.5 unit thength of bridge is being used to complete the diagonal bridge when the bridges are 9.5 and not 8.5 meters long?

I tried using equations with the two boards at the corner thing and found that there is still .1 meters that aren't acounted for from the outer corner to the inner corner. I'll show my work 'cause with a .1 unnaccounted answer I think I got something backwards and that should be the extra. So see if you can find my fault, please.

Firstly, once they are laid, there will need to be at least 4.6 meters that the bridge forming the triangle will need to cover from the corner to it's central point.
9.5 meter hypotinuse ( I know it's spelled wrong) squared gives you 90.25 meters squared.
(from here on is appr.)This divided by two gives you 45.125 meters squared on each side of the fomed triangle.
I divided by two because the lengths being equal will give you the longest tringle sides and will get you the closest to the castle..
The square root of this gives you 6.7175 meters on each side.
Halfway accross the bridge will be the closest point to the castle and halfway along each side of the formed triangle will line up exactly with the bridge's central point.
So, divide 6.7175 by two to get the distance from land to the bridge's center and you get 3.35 meters.
Note that both sides of the triangle will yield the same answer since they are the same measurments.
3.35 squared plus 3.35 squred gives you 4.73 meters that the hypotinuse bridge covers.


Okay, I guess I just had to go through it again. It does cover it.
For anyone who doesn't think this will work, look at this and prove it wrong.
P.S. I know it is really sloppy and crappy and yes, I did it in paint, but It doesn't change the fact.

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[Slick_Rick9009]

Also, Assuming it's an army andnot kids tht stuimbled upon it, then you didn't realize that he said that if jumping wouldn't work because of the board falling then you could fasten it to a tree with rope. Which would work, assuming you're in track and can jump that far. But, even if you can't do that then you could still put the other bridge accross the rest now that the first is fastened to the tree and can stand the weight. If it were kids that found it then, no, it would work. But We are supposed to be talking about an army, I'm sure they'll have a bit of rope with them. Finally, the question never states one bridge. If it did, then there would be no way except to climb up to stand on the very end and jumping as it falls into the moat and you lose it. Just look at the pics from earlier (one of the first posts, it has five or six frames) and imagine having someone stand on the end of the bridge in the third frame but without the board on the ground while they raise it and push it into the moat so the person could jump off onto the other side. This gets one person over. Completely useless. So saying that it implies a single bridge can't be right because then the above would be all you could do.

[wukupdemon]

but why do you say 8.5 unit thength of bridge is being used to complete the diagonal bridge when the bridges are 9.5 and not 8.5 meters long?

from the way i read it i assumed that the bridge can only be 9.5 M and only one bridge can be made. Therefore if one 1M was used on the diagonal, only 8.5M of bridge would be able to be made with the remaning material