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 06-04-2013, 06:34 PM #11836 Fbone Is that a sandwich?   Posts: 7,169 Karma: 88934460 Join Date: Jun 2010 Device: Searching ... Here's a quiz I guessed wrong. Physics is not my strong point. You're in a rowboat floating in a tank of water. There's a big rock in the boat and you decide to drop the rock into the water. The rock sinks to the bottom of the tank. Does the level of the water in the tank go up, down, or stay the same?
 06-04-2013, 07:28 PM #11837 Fat Abe Man Who Stares at Books     Posts: 1,725 Karma: 10606558 Join Date: Mar 2010 Location: 50th State, USA. Also, PA, NY, CA, and elsewhere. Device: All of the Above Down. While in the boat, the rock displaces a volume of water equal to the weight of the rock. (Archimedes Principle). In the water, the volume the rock displaces is equal to that of the rock. The answer depends on the rock having a greater density than the water. That is not true of all rocks, so then this becomes a trick question.
06-05-2013, 04:25 AM   #11838
pdurrant
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Quote:
 Originally Posted by Fat Abe Down. While in the boat, the rock displaces a volume of water equal to the weight of the rock. (Archimedes Principle). In the water, the volume the rock displaces is equal to that of the rock. The answer depends on the rock having a greater density than the water. That is not true of all rocks, so then this becomes a trick question.
As given, the only possible answer is the one you gave. The rock is described as sinking to the bottom of the tank of water. This would only happen if the rock is denser than the water.

If the rock were made of pumice, and so floated in the water, the water level would stay the same, as whether it was in the boat or in the water it would displace the same volume of water.

06-05-2013, 03:04 PM   #11839
Fbone
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Quote:
 Originally Posted by Fat Abe Down. While in the boat, the rock displaces a volume of water equal to the weight of the rock. (Archimedes Principle). In the water, the volume the rock displaces is equal to that of the rock. The answer depends on the rock having a greater density than the water. That is not true of all rocks, so then this becomes a trick question.
You're correct.

06-05-2013, 03:06 PM   #11840
Fbone
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Quote:
 Originally Posted by pdurrant As given, the only possible answer is the one you gave. The rock is described as sinking to the bottom of the tank of water. This would only happen if the rock is denser than the water. If the rock were made of pumice, and so floated in the water, the water level would stay the same, as whether it was in the boat or in the water it would displace the same volume of water.
That's precisely the reason. The rock sinking confirmed its density.

 06-05-2013, 09:47 PM #11841 Fat Abe Man Who Stares at Books     Posts: 1,725 Karma: 10606558 Join Date: Mar 2010 Location: 50th State, USA. Also, PA, NY, CA, and elsewhere. Device: All of the Above What if the tank were only 2" deep at the point of descent and the rock were 3" in diameter? Hitting bottom is not enough- the entire volume of the rock has to be immersed in water, or enough so that my reasoning applies. (Never argue with a lawyer-mathematician). Anyway, here is the next quiz. The World Science Fiction Society, at its convention (now called Worldcon), honors outstanding works of science fiction or fantasy with Hugo awards. One award category is for Dramatic Presentation. Some very fine films have won this prestigious award, including one of my favorite science fiction films (to be disclosed later). Name some of the winners. After 7 correct answers have been given, the mini-contest will be closed. Scoring is as follows. If you name the one unique winner, which is nothing like the others, then you get 6 points. All other correct answers get one point.
 06-05-2013, 10:30 PM #11842 Shayne Parkinson Author     Posts: 1,532 Karma: 5447804 Join Date: Jan 2010 Location: New Zealand Device: Samsung Galaxy Tab Hmm, thinking of ones I've actually seen that seem like candidates: 2001: A Space Odyssey The Lord of the Rings - FOTR The Lord of the Rings - TTT The Lord of the Rings - ROTK Dune Aliens Chronicles of Narnia - LWW Princess Bride Star Wars (the original three) Flash Gordon (from the early 1980s) Serenity No idea what the unique one might be, though.
 06-06-2013, 01:44 AM #11843 Fbone Is that a sandwich?   Posts: 7,169 Karma: 88934460 Join Date: Jun 2010 Device: Searching ... Raiders of the Lost Ark Blade Runner Most Unique I'd say was the Apollo Mission Disappointed that Logan's Run didn't win.
 06-06-2013, 04:55 AM #11844 Fat Abe Man Who Stares at Books     Posts: 1,725 Karma: 10606558 Join Date: Mar 2010 Location: 50th State, USA. Also, PA, NY, CA, and elsewhere. Device: All of the Above Shayne 7 (max) pts for 2001: A Space Odyssey, Lord of the Rings FOTR, TT, ROTK, Aliens, Princess Bride, Star Wars ep. 4-6, Serenity Fbone: 7 (max) pts for the Apollo Mission coverage, Raiders and Blade Runner. That's a tie for winner. You two can decide who hosts the next quiz. The Apollo Mission TV reporting shows are unique in that they are the only non-fiction production(s) to ever win this major award, afaik.
 06-06-2013, 04:16 PM #11845 Fbone Is that a sandwich?   Posts: 7,169 Karma: 88934460 Join Date: Jun 2010 Device: Searching ... Here's a quickie: The bells of the clock tower signal six o'clock with 6 loud rings, taking 5 seconds to do so. How long will it take for the bells to signal twelve o'clock?
 06-06-2013, 05:25 PM #11846 pdurrant The Grand Mouse 高貴的老鼠     Posts: 49,344 Karma: 168370917 Join Date: Jul 2007 Location: Norfolk, England Device: Kindle Voyage 11 seconds.
 06-06-2013, 05:26 PM #11847 Bilbo1967 Not scared!     Posts: 11,047 Karma: 55282075 Join Date: Mar 2009 Location: Midlands, UK Device: Sony 600, Sony 650, Sony T2, Xoom, Nexus 7 (2012 & 2013), Nook ST (x2) Would "not 10 seconds" get me any points?
06-06-2013, 05:30 PM   #11848
pdurrant
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Quote:
 Originally Posted by Bilbo1967 Would "not 10 seconds" get me any points?
We shall have to wait and see, but (given my answer just above yours), I'll be surprised if it did!

06-06-2013, 07:06 PM   #11849
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Quote:
 Originally Posted by pdurrant 11 seconds.

It will take 11 seconds. The five seconds needed to signal six o'clock are the 5 silent intermissions between rings. At 12 o'clock, the 12 rings are separated by 11 silent intermissions, thus 11 seconds for the clock to ring 12 times.

 06-07-2013, 04:36 AM #11850 pdurrant The Grand Mouse 高貴的老鼠     Posts: 49,344 Karma: 168370917 Join Date: Jul 2007 Location: Norfolk, England Device: Kindle Voyage I must have been tired last night - I completely mis-read Bilbo's comment. Oh well. Hmm... A quiz question. OK, another from Richard Wiseman. I blindfold you, and give you a pack of cards. I tell you that ten of the cards in the pack are face-up, and the rest are face-down. I ask you to use the whole deck to make two piles of cards, and each pile must contain the same number of face-up cards. How do you do it? (No, the cards aren't marked, and you can't feel the difference between a face-up and face-down card by touch.) Last edited by pdurrant; 06-07-2013 at 03:56 PM.