Sunday 29 August 2010

Brain-teasers

Here’s a couple of brain-teasers for you. Put your answers in a comment below.

1]  A certain city has two prominent sports teams, one of which dresses in a blue strip the other in green. The teams are rivals, as are their supporters; additionally each group of supporters is allied to a rival Christian sect. The supporters of the blue team are noted for their attachment to royalty and are nicknamed “Huns”. Often, when the two sets of supporters meet violence breaks out. What city am I talking about?

2]  In a certain city in the 20c there was a famous occasion when tanks were deployed against civilian protesters. What city am I thinking about?

My answers another time.

3]  Here’s one I don’t know the answer to, but I would be grateful if anyone else can provide the definitive solution. It comes from another person’s blog. Two men (it happened to be Keats and Chapman, but that’s not really relevant) were in a boat in the middle of a lake. There was a large house brick in the boat. One of them picked up the brick and dropped it into the water. Did the water level in the lake go up, go down, or stay the same, and why?

PLEASE – or I’ll go barmy thinking about it.

___________________   


Consuela (my Tejana maid) is reminding me that I said I would mention the Wes Studi business. Yes, yes… later, later…

Memo to self: do not blog at breakfast time – you get marmalade on the keyboard. (Damn)


picture (c) Jeff Widener, reproduced by kind permission

14 comments:

  1. Any floating object will displace the same weight of water as the object weighs. Thus if the brick had the same density as water the water level would stay the same. The brick however is denser than water and so while floating displaced a greater volume of water than its own volume, now it has sunk it only displaces its own volume.

    An easy way to think of it is to consider the opposite event. Suppose a large balloon full of air were to be tethered to the bottom of the lake, if the rope broke the balloon would float to the top where it would displace almost no water so the level of the lake would sink.Or running time backwards if you have a full bucket of water with a balloon floating on the top, if you push the balloon down the bucket will empty!

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  2. Jeff beat me to the comment on the third question. Ditto.

    Eilidh

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  3. Eilidh - have a go at the first two questions, before Jeff does (or just shut your eyes next time you visit) :)

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  4. I assume the answer to number two would be Beijing (Tiananmen Square)?

    Someone else can take number one. I'm hopeless with sports teams!

    Eilidh

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  5. Interesting, Eilidh, interesting...

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  6. But perhaps in scenario 3, either Keats or Chapman were tied to the brick...so surely that might displace even more water in the lake than just the brick alone?

    ...But then, the boat (presumably still floating in the middle of the lake) would be that much lighter, and so perhaps NO discernable displacement would occur. Therefore, the answer would be "The Same".

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  7. You asked: Two men were in a boat in the middle of a lake. There was a large house brick in the boat. One of them picked up the brick and dropped it into the water. Did the water level in the lake go up, go down, or stay the same, and why?

    This is my answer, right or wrong...

    I say the water level went down and this is why:

    (1) while the brick was in the boat its weight added to the total amout of water that the boat displaced

    (2) with the same brick in the water the weight of the brick was offset by the bouyancy effect of the water and therfore in effect weighed less than it above water weight


    This reasoning may be flawed but that is my humble take on the query.

    Dennis (haiku-bless-you at AllPoetry)

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  8. Right conclusion, Dennis, but as you know - your reasoning is missing the stumps by an inch or two. See the entry for 30th August (just coming up).

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  9. Am way too late to agree with Eilidh and Jeff, but the first one stumps me; am too much Canadian to decipher...DW

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  10. Would it help if the lake in question were the Great Bear Lake?

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  11. probably not, lol!...DW

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  12. The answer to the first question is Glasgow. The Rangers football club team wear the blue, and are nicknamed the "huns". Their fierce rivals, the Celtic football club team, wear the green.
    Celtic is supported by the Glasgow Catholic community, the Rangers by the Protestants.
    Ugly sectarian violence between their respective supporters has recently led to the deaths of some.
    My brainpower in providing these answers is limited to having done a few searches on Google, using the key terms provided in the question. Is that cheating? I would never have known otherwise.
    Ian ['Seasinger' in AP]

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  13. Ian, you have actually walked into the trap I set. Look here for the answer: http://mairibheag.blogspot.com/2010_08_01_archive.html

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