Only For Geniuses

Robbie · Post by **Robbie** » Sun May 08, 2016 10:55 pm

WLLady wrote:QR_BBPOST So...burning fuse....light both ends and then 4 other places in the middle... 60sec burning fuse lit in 6 places should burn out in 10 seconds aslong as theres always 6 burning spots.
And this really would only work if the fuse burns steadily and one has 6 hands to relight and and and..

I'll have to think about this one some more. This is going to bug me until I get it! But Don't you have to light 7 places to get 6 pieces of fuse burning from both ends?

Post by **poultry_admin** » Mon May 09, 2016 6:56 am

Robbie wrote:QR_BBPOST OK got Jim and Tom, just wanted to clarify the fuse- one fuse, one minute to burn?

Yes, one fuse that burns for one minute and you are trying to get 10 seconds from that.

Robbie · Post by **Robbie** » Mon May 09, 2016 8:46 am

This one still bugs me. Since we can't measure it, we can't divide the fuse up to light it in equal lengths. Otherwise the correct answer for the 45 second fuses would be just light one fuse 3/4 of the way along the length. So this has to work lighting the fuse anywhere in multiple places to get the 10 seconds.

Post by **poultry_admin** » Mon May 09, 2016 5:29 pm

Robbie wrote:QR_BBPOST One of my favourites- "proving" that 1=0. Can you spot the mistake?

► Show Spoiler

Robbie · Post by **Robbie** » Mon May 09, 2016 5:44 pm

Correct, PA!

It's true, the universe instantly gets sucked down a giant black hole if we divide by 0

Post by **poultry_admin** » Mon May 09, 2016 5:57 pm

YAY

The fuse one bugs me, too.
The 45 sec fuse it would be easier if you made a T with the two fuses and light all three ends and hope that the spark jumps at the intersection between the two fuses.

For the 10 sec one, you have to be really really fast to keep 6 flames going at all times. Not sure how accurate that would be?

Seastar · Post by **Seastar** » Mon May 09, 2016 8:56 pm

would one fuse be 4x the length of the other fuse?

Post by **WLLady** » Tue May 10, 2016 8:02 am

i would much rather use the fuse to detonate a pile of TNT at the end....go "ooooooooo aaaaawwwwwww" and be done with it. LOL

fuses have the curious behaviour of apparently not burning consistently, so the length of the fuse would not matter, if the fuse burns in entirety in 1 minute it could do that by burning half in 30 sec or half in 10 seconds....either way it burns completely in 1 minute. so if you keep the thing lit in 6 places - or maybe 7....robbie, you have me thinking....-it should be completely burnt in 10 seconds because 6x10=60. no, should be 6 places, because the flame from the fuses will go in both directions....
but one couldn't possibly keep 6 places lit at all times-not physically anyways.

which leads me to one question: when on earth, will i ever use this kind of math, in the future? LOL. (funny, i don't use derivatives either anymore).
sorry, grade 13 math teachers ;-P

Robbie · Post by **Robbie** » Tue May 10, 2016 9:38 am

WLLady wrote:QR_BBPOST i would much rather use the fuse to detonate a pile of TNT at the end....go "ooooooooo aaaaawwwwwww" and be done with it. LOL

fuses have the curious behaviour of apparently not burning consistently, so the length of the fuse would not matter, if the fuse burns in entirety in 1 minute it could do that by burning half in 30 sec or half in 10 seconds....either way it burns completely in 1 minute. so if you keep the thing lit in 6 places - or maybe 7....robbie, you have me thinking....-it should be completely burnt in 10 seconds because 6x10=60. no, should be 6 places, because the flame from the fuses will go in both directions....
but one couldn't possibly keep 6 places lit at all times-not physically anyways.

which leads me to one question: when on earth, will i ever use this kind of math, in the future? LOL. (funny, i don't use derivatives either anymore).
sorry, grade 13 math teachers ;-P

Buuuuttttt.... if you light the fuse in 6 places, you get 5 pieces burning from both ends, don't you need 6 pieces if they take 10 seconds to burn each? so to get 6 pieces that's lit in 7 places. No?
That's assuming the fuse burns evenly from both ends. But if it doesn't burn evenly, I don't know how you could solve either problem (including the 45 second one) unless you use the total time for a complete burn. If you divide the fuse up in 6 pieces, and the fuse burns unevenly, you can't assume that each piece will burn in 10 seconds. All you know is it takes a total time of one minute for the fuse to burn completely. So I still don't understand how you would get the 10 seconds by lighting whatever pieces of fuse. For example, one segment could take 50 seconds to burn, the other five could take 2 seconds each so the entire fuse is burnt in 1 minute but how do you get 10 seconds from that? I'm still stuck on figuring out how keeping 6 (or 7) ends going gives you an average time of 10 seconds.

Maybe this is why those pyro guys set themselves on fire all the time!

I know my head is going to explode from this problem soon!

Post by **WLLady** » Tue May 10, 2016 9:40 am

Soooo if you light 6places (or 7...? Still thinking about that) the entire fuse should burn in 10 seconds....