Too Classy For Words

E4
So there's this serious looking and severely stern teacher who's invigilating an important class test one day, and he's determined to go strictly by the rules. In a stentorian voice, he warns the hall full of hopefuls, who are raring to ace the paper, that everyone has to stop writing, as soon as the three o'clock bell begins to ring. Then he leans forward and watches like a hun-gry hawk to see if anyone dares to transgress the law even by a femto-second, because if they do, then by golly he's going to throw the book at them.
Sure enough, the bell rings on the three-ticker, dead on time, but one student ignores the warning and merrily continues writing for a few minutes longer. When he finally stops and drops his test booklet on top of the others on the table, the professor picks it up and hands it back with a snarl.
"You were told to stop writing when the bell rang. Since you didn't, you automatically fail," he growls. Hearing this, the student demands indignantly in a loud voice, "Do you know who I am?" The professor replies, "No, and what's more, I don't care."
The question is, what can the student do now to avoid failing the test?
DEAR MS
(The older problem was: "Can a log of wood be constantly accelerated to be propelled fast enough through water to cause burn marks on its surface? You know, like small meteors vaporise while going through Earth's atmosphere." - MS)
Wood-U-Believe-It Dept:
Wood typically ignites at about 300-600°C. If we were to accelerate the wood fast enough to reach high temperatures, at 100°C, the water would start to evaporate and take away this heat. The wood wouldn't burn. But it is possible that it would be sort of cooked with the heat and steam!! So NO, definitely no burn marks.
Dr Shyam, orthoshyam@gmail.com
(The other problem was to find out who among the couples A, B and C was the thief from the six clues provided. - MS)
Robbing-Hood-Dept:
Mrs B is established as the thief, as follows: Mr C is in a crutch and could not have played tennis and hence could not have been the thief that lost to Mr B in tennis (Clue 6). Mrs C couldn't be the thief since her spouse won at cards (Clue 1). Mrs B's non-card playing female companion had to be Mrs A, since Mrs C played cards (Clue 3 and 5). It is not A or B since neither of their wives could have lost money since neither played cards (Clue 1 and 3). It is not Mrs A since B could not have beaten her in the mixed doubles tennis match; he would have known her if she had played (Clue 4). To reconfirm, Mrs B's spouse Mr B lost money at cards; hence Mrs B satisfies Clue 1. Elementary Dr Watson!
Ramesh (Sherlock) Mahalingam, ramesh@idealmc.com 
(The third problem was: "Why is a pan balance having same weights placed on both the pans only be stable with the rod in the horizontal position?" - MS)
Panning-The-Puzzle Dept:
The question is why doesn't the balance stay put in positions other than horizontal, since the balancing torques remain equal and opposite even when the beams are not horizontal? The answer lies in the construction of the balance. Look closely at a real balance!
Alan D'Souza, iamaland@gmail.com 

ENDGAME(S)
1. A bag contains a counter, which may be either black or white. A second counter, which is definitely white, is put into the bag. The bag is shaken and one counter taken out, which proves to be white. What is the probability of the next counter coming out of the bag also being white?
2. You're marooned on a desert island with a friend who claims he's memorised pi up to 100 places. If you have no books, computer, mobile or a calculator, how can you verify the 100 digits he is rattling off are not gibberish?
(To get in touch with Mukul, mail him at mukul.mindsport@gmail.com  

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