Castle

[Guest]

you people complicate everything. tis as simple as this: the footbridge is made out of wood, correct? or so everyone seems to assume. anyways... DOESN'T WOOD FLOAT??

[Guest]

This seems to be a much better solution.

[Guest]

well thank you very much :]

[Guest]

Deven, please don't tell me you're going to post without reading even a fraction of the previous posts. It was already mentioned that you could float on the obviously wooden footbridge. It has also already been stated that it won't work. Whose to say that the bridge is able to hold that many people and it STILL float? Or, are you so sure that the moat has a high enough water level that you can get back off the bridge on the other side? Not trying to be rude, just mention that there's nothing said that would insure that plan. You have to go with what is given. Finally, you said everyone on here overcomplicates things. They overcomplicate it on purpose so they can stretch their brain-muscle (before anyone says anything, yes, I DO know the brain is not a muscle). They are trying to get themselves thinking. They're not doing it because they don't see the simple way.

[Guest]

Okay... first of all, there's what? SIX PAGES of posts. Its not like I go and read every single one (sorry if I offend anyone); however, I see no reason for you to get on my case. The first amendment of the constitution states my right to freedom of speech so I would greatly appreciate my rights thank you.

[Guest]

Sorry, I didn't mean for it to sound so offending. The I was thinking it, it really wasn't rude. But, when I typed it, I guess that's how it ended up. I appologize that you thought I was "getting on your case" but I was just pointing it out. Again, sorry.

[Guest]

Dont even worry about it. Its totally cool. I understand where you're coming from. I'm actually a really chill person and I apologize to you- I can get a bit carried away at times and sound like a total... brat I guess i'm trying to say. But yeah, its instinct for me- i'm a hard core policy debater. So- thats all past now and i'm ready to move on in life haha but thank you for apologizing. It means a lot. All good??

[Guest]

Okay let's see:

You don't have any way to brace the pieces if you put two of them together, unless you use a the shorter bridge to shore up the middle by sicking it into the moat.

You could put one across a corner and run the other one from that one across, like in a letter T.

Or you could run just one and move the end sideways unti it fits. You didn't give any length on the sides of the square. So say you put one end on the outside edge of the moat and then just inched it over until it fits sort of diagonally.

Then again you could run onw of the long ones across a corner and use another one further down, then run a short one from the bank to the first long one , then another short one from there to the second long one, then another short one with the end resting one the second long one kinda sideways to the other bank.

it would look like a + sign with two long arms and a kinda crooked bottom arm.

Or you could lay three long ones across a corner and zig zag the short ones across.

[Guest]

Swimming seems like the easiest answer to me.

[Guest]

Castle - Back to the Logic Puzzles

A square medieval castle on a square island was under siege. All around the island, there was a 10 metre wide water moat. But the conquerors could make foot-bridges only 9.5 metres long. Nevertheless a wise man was able to figure out how to get over the water. What do you think was his advice?

(There's a place on the other side to put the bridge against, not just a sheer wall. the water moat has square corners - that section of the moat is about 14.1 metres wide.)

Castle - solution

You can put one foot-bridge over one corner (thus a triangle is created). Then from the middle of this foot-bridge lay another foot-bridge to the edge (corner) of the castle. You can make a few easy equations confirming that this is enough.

If the wise man was so frickin wise then why the hell couldn't he just figure out how to put another measly half of a meter onto the foot bridge? He could do all that and yet a half of a meter was some kind of enigma?

[Guest]

Simple Trig using two 9.5m ladders where the sections of moat along two sides meet.

place first ladder diagonally across the ouside corner of the moat so that the end only just bears on the outer edges of the moat on either side of the castle.

at the midspan of the ladder you will be above the moat, 4.75m from the outer corner and 9.39m form the inner corner. just close enough to span across with the second 9.5m ladder by supporting it on the first ladder at midspan.

[Guest]

i think his advice was.....build boats

[Guest]

A square medieval castle on a square island was under siege. All around the island, there was a 10 metre wide water moat. But the conquerors could make foot-bridges only 9.5 metres long. Nevertheless a wise man was able to figure out how to get over the water. What do you think was his advice?

- If the moat was around the island, wouldn't they be able to go right up to the island itself?

[Guest]

This should work. The diagonal solution should work too with 9.5 m planks.

bridge.bmp

Edited January 10, 2008 by MurrayMD

[Guest]

This should work. The diagonal solution should work too with 9.5 m planks.

While the diagnol solution seems to be the best, it seems it would also be possible only using one foot bridge. By using a large stone or other heavy enough object, you could place the bridge on the shore and hold it in place with the stone. This would cover about 9 meters of the moat, leaving about 1/2 meter to secure the bridge to the ground with the stone. Then people could walk across and jump the last meter over the moat.

[Guest]

if they can connect bridges, why don' they just make smaller ones and connect them?

[Guest]

Take one footbridge and place it across a corner of the moat. Another bridge at a right angle to the center of the first bridge will reach land.

[Guest]

Connect the footbridges width-ways to make a square (for example). Rotate the square to a diamond shape and have opposing points on each side of the moat.

Edited February 20, 2008 by Oblivion

[Guest]

I would make a diving board and then let them jump across..

[Guest]

you tie rope and a hook(s) onto the portable bridge then throw the rope and hook until it catches onto the other side then secure the hook onto the ground by u orhave somone hold it. presto bridge.

[Guest]

I would just put 1 bridge across the corner and the other from the middle of that bridge the edge of the island. Like so:

This will not work as the maximum length you can achieve with this approach is 9.5 + 4.25 = 13.75

As illustrated below in the picture.

Since angle and A and B are same, the sides AC and BC has to be same.

AC is half of max length of bridge, which is 9.5/2 = 4.25.

Edited March 18, 2008 by holla

[Guest]

This will not work as the maximum length you can achieve with this approach is 9.5 + 4.25 = 13.75

As illustrated below in the picture.

Since angle and A and B are same, the sides AC and BC has to be same.

AC is half of max length of bridge, which is 9.5/2 = 4.25.

Sorry, I wrote saying this will not work based on some arithmetic, but then I realized that I made a simple mistake while halving 9.5 :-(

I was not able to delete the post.

This is the perfect solution. My apologies.

[Guest]

I like fosley's solution as compared to the "normal" T solution, but I believe he made an error in the following statement:

."...... I'm not sure of the exact physics, but I know that the maximum mechanical disadvantage for the guy holding the board down is 10:8, or 1.25, and that would occur when someone was standing at the very opposite edge of the moat. So 2 guys on the end away from the castle would be sufficient for 1 guy to cross the bridge."

I believe only ONE person outside the moat could hold up to 5 people crossing the bridge built like this(assume the boards can hold them, don't flex and weigh nothing). His mechanical advantage is smallest at the end of HIS board or 8/1.5 = 5.33x. As the weight/people move away from the end of his board(on the other board), his demand gets lower since the weight will be increasingly supported by the ground on the opposite shore.

Thanks again for this different solution.

[Guest]

im not altogether sure what i should think about your little diagrams and the fact that you (fosley) took so much time and effort to write an essay and do proper diagrams to explain your theory.

however, my first thought on solving this one was the same as undeniable's.

does anyone actually know the correct answer or shall we forever be in suspense???

[rookie1ja]

im not altogether sure what i should think about your little diagrams and the fact that you (fosley) took so much time and effort to write an essay and do proper diagrams to explain your theory.

however, my first thought on solving this one was the same as undeniable's.

does anyone actually know the correct answer or shall we forever be in suspense???

I do know the correct answer and I wrote it in the very first post