34
   

The worlds first riddle!

 
 
markr
 
  1  
Reply Wed 16 Feb, 2005 10:16 pm
GOLF
First ball: angle = 45 degrees, speed = 120 ft/sec, elapsed time = 5.3033 seconds
Second ball: angle = 22.5 degrees, speed = 64.9435 ft/sec, elapsed time = 5.3033 seconds

64.9435/120 = a bit more than 54%

Notice that the balls arrive in the cups at the same time.
0 Replies
 
markr
 
  1  
Reply Wed 16 Feb, 2005 10:25 pm
1934 DISMISSAL
Edmund Landau (googled again)
0 Replies
 
Tryagain
 
  1  
Reply Thu 17 Feb, 2005 06:29 am
Mark:
1934 DISMISSAL
Edmund Landau Cool


It is almost unbelievable that a definition of pi was used, at least as an excuse, for a racial attack on the eminent mathematician Edmund Landau in 1934. Landau had defined pi in this textbook published in Göttingen in that year by the, now fairly usual, method of saying that pi/2 is the value of x between 1 and 2 for which cos x vanishes. This unleashed an academic dispute which was to end in Landau's dismissal from his chair at Göttingen. Crying or Very sad





Mark:

GOLF
First ball: angle = 45 degrees, speed = 120 ft/sec, elapsed time = 5.3033 seconds
Second ball: angle = 22.5 degrees, speed = 64.9435 ft/sec, elapsed time = 5.3033 seconds

64.9435/120 = a bit more than 54% Cool

Notice that the balls arrive in the cups at the same time. Cool


Well done people, we won the cup. (Nice putt Mark) Laughing




On the first hole, suppose the ball's initial speed is (v), at an initial angle (b) up from the horizontal. Its horizontal velocity is then (v cos b). Its initial vertical velocity is (v sin b). Letting (g) be the acceleration due to gravity, we see that after time (t = 2 v sin b / g) the vertical velocity will have changed from (v sin b) to (- v sin b), and the ball will have returned to its initial vertical position. Let (D=150 yards) denote the horizontal distance of this hole, and observe that in time (t) the ball has travelled a horizontal distance of (t v cos b), leading to the equation:

D = (v^2 /g) 2 sin b cos b,
or
D = (v^2 /g) sin(2b).

To maximize the horizontal distance for a given initial speed (v), we must maximize (sin(2b)), which we do by setting (b=45 degrees), whence (sin(2b)=1), and v = sqrt ( D g ).

On the third hole, denote the initial speed as V, the initial angle above the horizon as B, and the total time as T.
The horizontal distance will be

D / sqrt(2) = T V cos B.

The average vertical velocity will be

V sin B - (T/2) g,

so that the total vertical ascent will be

- D / sqrt(2) = T ( V sin B - (T/2) g ).

Solving for (V):

V^2 = D g / ( 2 sqrt(2) * (cos B) * (sin B + cos B) ).

Use the identity:

(cos B)*(sin B + cos B) = (1/2) + (1/sqrt(2))*sin(2B+45)

to deduce that (V) will be minimized when (B=22.5 degrees), with a ratio

V/v = sqrt ( 1 - 1/sqrt(2) ) = 0.5412.

On the third hole, the golfer hits the ball at 54.12% of the speed that was required on the first hole. Shocked



The physicist Willebrord Snell (1580-1626) found polygons which better approximated the perimeter of circles than do inscribed and circumscribed polygons. Better perimeter approximations lead to more quickly converging pi approximations. What scientific discovery is Snellius best known for Question

• the laws of reflection and refraction
• general relativity
• exploding pop-tarts
• the photoelectric effect
• the uncertainty principle in quantum mechanics



How many zeros are at the end of 100000! Question
0 Replies
 
Liessa
 
  1  
Reply Thu 17 Feb, 2005 08:30 am
ZEROS
1, the rest of them aren't at the end...

SNELLIUS:
A. I knew it, but googled to be sure. He was Dutch, like me!

How man apples can you take from a full basket?
0 Replies
 
markr
 
  1  
Reply Thu 17 Feb, 2005 11:51 am
ZEROS
24999

APPLES
One - after that it isn't full
0 Replies
 
Tryagain
 
  1  
Reply Fri 18 Feb, 2005 05:06 am
Liessa from the land of Tulips and Windmills. Did make me laugh. Laughing


How many zeros are at the end of 100000!


ZEROS
1, the rest of them aren't at the end... (See answer below from Mark who nailed it)



SNELLIUS:
A. I knew it, but googled to be sure. He was Dutch, like me! Cool


The missing answer is:
• the laws of reflection and refraction

Willebrord Snell studied law at the University of Leiden but was very interested in mathematics and taught mathematics even while he studied law. From about 1600 he travelled to various European countries, mostly discussing astronomy. In 1602 he went to Paris where his studies continued. He received his degree from Leiden in 1607.

Snell's father, Rudolph Snell (1546-1613), was professor of mathematics at Leiden and, in 1604, Willebrord visited Switzerland with his father. In 1613 he succeeded his father as professor of mathematics at the University of Leiden.

In 1617 Snell published Eratosthenes Batavus, which contains his methods for measuring the Earth. He proposed the method of triangulation and this work is the foundation of geodesy.
Snell also improved the classical method of calculating approximate values of p by polygons. Using his method 96 sided polygons give p correct to 7 places while the classical method yields only 2 places. van Ceulen's 35 places could be found with polygons of 230 sides rather than 262.

(Anybody still awake?)
Although he discovered the law of refraction, a basis of modern geometric optics, in 1621, he did not publish it and only in 1703 did it become known when Huygens published Snell's result in Dioptrica. Snell also discovered the sine law.

Snell studied the loxodrome, the path on the sphere that makes constant angle with the meridians. This appears in Tiphys batavus published in 1624, a work in which he studied navigation.




"How man apples can you take from a full basket?"


This is an intriguing question. There can be physical limitations, or the contents match the external specifications. However, in an open container, Can you ?'take' them all at once?


Enter stage left Mark, our resident citrus expert, "APPLES One - after that it isn't full"

When is ?'full', ?'full'?



However, one answer that is not subject to any form of debate:


Mark:
ZEROS
24999 Cool


We need to find min(e2(100000!),e5(100000!)), where ep represents the coefficient of the prime p in the prime factorization of 100000!. It is clear that there are less factors of 5 than of 2 in n!, so we proceed to find instead the factors of 5 in 100000!. They are, from Legendre's formula.

Which is equal to: 20000 + 4000 + 800 + 160 + 32 + 6 + 1 = 24999 .



A book contains the following paragraph, implying that pi=3:
"And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it about."

What book does this come from?
• Douglas Adams' Hitchhiker's Guide to the Galaxy
• A Brief History of Time by Stephen Hawking
• The Bible
• Ulysses by James Joyce
• Homer's Odyssey



A club contains a finite number of members.
Some pairs of these members are friends (see the "fine print" below).They meet once a week and each member drinks one cup of either tea or coffee. At the first meeting each selects his favorite drink, but starting from the second week he chooses what to drink according to the following rule:

He remembers what each of his friends drank last week and chooses what the majority of them drank. If there was a tie (an equal number of coffee and tea drinkers among them) he drinks the same as he did last week.

Now suppose this club runs forever. It is easy to see that this process eventually becomes periodic because each state depends only on the previous one and there are only a finite number of possible choices.


Question 1:
Can you prove that the eventual period is 1 or 2 Question

Question 2:
Is it possible to show a club with 1000 members might run 18 years before reaching its periodicity Question
Can it go longer Question

( "Friendship" is symmetric but not reflexive and not necessarily transitive. This means that if Bob is Charlie's friend then Charlie is Bob's friend; Bob is not his own friend; if Bob and Charlie are friends and Charlie and David are friends, we cannot conclude whether or not Bob and David are friends. Also, friendships are permanent: Bob and Charlie are friends this week if and only if they were friends last week. Club membership is also permanent. So we're talking about an undirected graph with no loops or multiple edges -- same as always.)
0 Replies
 
Liessa
 
  1  
Reply Fri 18 Feb, 2005 11:22 am
PI
The Bible. When I was in college, this quote was in one of our first courses on goniometrics (is this the english word?). It's in the book of I Kings 7: 23 and reappears in II Chronicles 4: 2. Yes, I got my Bible out and looked for it.

markr:
APPLES
One - after that it isn't full

tryagain:
This is an intriguing question. There can be physical limitations, or the contents match the external specifications. However, in an open container, Can you ?'take' them all at once?

hmmm, that's an interesting question. If there aren't too amny, that could be possible, but when some ar on top of others, this quickly becomes impossible, as you are not strictly speaking taking all at once.

Yup, that was my answer...
0 Replies
 
markr
 
  1  
Reply Fri 18 Feb, 2005 10:04 pm
CLUB
Not I.
0 Replies
 
Tryagain
 
  1  
Reply Sat 19 Feb, 2005 09:58 am
Liessa writes, "PI The Bible. When I was in college, this quote was in one of our first courses on goniometrics (is this the English word?). It's in the book of I Kings 7: 23 and reappears in II Chronicles 4: 2. Yes, I got my Bible out and looked for it."

a) It proves your college education was not wasted. Cool
b) ?'goniometrics' I take it you were studying little garden Gnomes. :wink:
c) Religion arrives in the Riddles forum, and not before time either. Laughing


So according to the Bible it's an even 3 (if it was ten cubits across, and thirty cubits around, then this would mean that pi equals three). The Egyptians thought it was 3.16 in 1650 B.C.. Ptolemy figured it was 3.1416 in 150 AD. And on the other side of the world, probably oblivious to Ptolemy's work, Zu Chongzhi calculated it to 355/113. In Bagdad, circa 800 AD, al-KhwarizmiD agreed with Ptolemy; 3.1416 it was, until James Gregory begged to differ in the late 1600s.

Part of the reason why it was so hard to find the true value of Pi (π) was the lack of a good way to precisely measure a circle's circumference when your piece of twine would stretch and deform in the process of taking it. When Archimedes tried, he inscribed two polygons in a circle, one fitting inside and the other outside, so he could calculate the average of their boundaries (he calculated π to be 3.1418). Others found you didn't necessarily need to draw a circle: Georges Buffon found that if you drew a grid of parallel lines, each 1 unit apart, and dropped a pin on it that was also 1 unit in length, then the probability that the pin would fall across a line was 2/π. In 1901, someone dropped a pin 34080 times and got an average of 3.1415929.

Like all these men noticed, everyone everywhere at anytime who's tried to find π have all come up with pretty much the same number, with some more precise than others. It didn't matter if you tried it on the other side of the world, or got your brother to do it, or let the circle relax a bit before trying again, or snuck up on it when it wasn't looking, or waited until mom and dad had gone to bed before creeping down to the study on tiptoe to catch it by surprise, the ratio of a circle's diameter and circumference still was, is, and always will be

3.1415926535897932384626?-and so-on and so-on and so-on...







APPLES
markr:
One - after that it isn't full

Yup, that was my answer...

Yes, he was right again. Laughing

Mark:
CLUB
Not I. Shocked

Mark sets his own riddle. ?'Not One' , ?'Not Eye' , ?'One eye'.

Let t=1 denote the first week.
For member x, let x(t) denote either "Coffee" or "Tea", whichever member x drinks in week t.
(We are resisting the impulse to joke about drinking weak tea during week t.)

For t>1, define g(x,t) to be twice the number of friends y of x such that
x(t)=y(t-1), plus one if x(t)=x(t-1).
For t>2, define h(x,t) to be twice the number of friends y of x such that
x(t-2)=y(t-1), plus one if x(t-2)=x(t-1).

For t>1, define f(t) to be twice the number of pairs (x,y) of friends such that x(t)=y(t-1) (both (x,y) and (y,x) should be considered), plus the number of members x such that x(t)=x(t-1).

Claim 1: f(t) = sum g(x,t), where the sum runs over members x.

Claim 2: f(t-1) = sum h(x,t), where the sum again runs over x. (This uses the fact that if (x,y) is an edge then (y,x) is an edge.)

Claim 3: g(x,t) is at least as large as h(x,t).
That's because they differ only in the choice of x(t), and x(t) is chosen to make g(x,t) as large as possible, because of the majority vote with the tie-breaker.
Further, g(x,t)=h(x,t) only if x(t)=x(t-2). (If x(t) is different from x(t-2) then exactly one of g(x,t), h(x,t) is even and the other is odd.)

Clearly f(t) is an integer function of t.
Also f(t) is at least as large as f(t-1), with f(t)=f(t-1) only when x(t)=x(t-2) for all x.
Also f(t) is nonnegative, and it is bounded above by 2N(N-1)+N, where N is the number of members.
Wait until f hits its maximum at f(T); then for all t>T+1, we have x(t)=x(t-2). So the club's behavior is periodic with period 1 or 2 after time T.

An example of period 2 is a bipartite graph: the only friendships are between men and women, all men initially drink tea and all women initially drink coffee. Then each week they exchange roles.


Answer 2:

A club with 1000 members that has the friendship graph
1--2--3--4--...--998--999--1000 and starts with the assignment (1,1,0,1,0,1,0,1,...,0,1) (i.e. all even-numbered members, as well as member 1, drink coffee on the first week, and tea for all odd-numbered members except member 1), will run for 998 weeks before settling into an all-coffee regime on the 999th week.





It has been proven impossible to "square the circle." What does it mean to square the circle Question

• multiply a circle by itself
• construct a square that perfectly circumscribes a circle
• use a straightedge and compass to construct a square equal in area to a given circle
• determine the value of pi squared
• draw a circle with area equal to pi * (r squared)



A weekend of fun and laughter! Rolling Eyes

The A two Know Universal H.P. Challenge.
15 questions to be crowned chief Mucklepuklock. Twisted Evil


Harry Potter

1. What is the name of the sixth Harry Potter book Question

2. What is J.K. Rowling's middle name Question

3. The sixth Harry Potter book will be published on 16th Question 2005.

4. Who plays Harry Potter in the film series Question

5. What film certificate did Harry Potter and the Prisoner of Azkaban receive when it was released in the UK Question

U

PG

12A

15

6. What is the name of the second book in the series Question

7. What is a 'muggle' Question
0 Replies
 
Liessa
 
  1  
Reply Sat 19 Feb, 2005 12:05 pm
SQUARE THE CIRCLE
- use a straightedge and compass to construct a square equal in area to a given circle

Our teachers made us try this in college. They are evil...

Yes Tryagain, we had a book with pictures of all sort of gnomes. How did you know?

HP
1 HP and the Half Blood Prince
2 Kathleen
3 July
4 Daniel Radcliffe
5 PG
6 HP and the Chamber of Secrets
7 a non-magical person. So, for example, me.
0 Replies
 
Tryagain
 
  1  
Reply Sun 20 Feb, 2005 06:36 am
Liessa:
SQUARE THE CIRCLE
- use a straightedge and compass to construct a square equal in area to a given circle. Cool



"Our teachers made us try this in college."

All good practice should you wish to join the magic circle. Laughing



"we had a book with pictures of all sort of gnomes. How did you know?"




Due to a somewhat embarrassing incident when I used to own a horse stud farm. One day a friend phones me up and says, 'there's this gnome with a speech impediment I know who wants to buy a horse, so I've sent him round to see you.' Sure enough the gnome turns up.

I ask him, 'do you want a male horse or a female horse?' 'A female horth', the gnome replies. So I show him a mare. 'Nith horth', says the gnome, 'can I thee her eyth?' So I pick up the gnome to show him the horses eyes. 'Nith eyth', says the gnome, 'can I thee her teeth?' Again I pick up the gnome to show him the horses teeth. 'Nith teeth, can I see her eerth?' the gnome says.

By now I was getting a little fed up but again I pick up the gnome to show him the horses ears. 'Nith eerth' he says 'now, can I see her twot?' With that I pick up the gnome and shoves his head deep inside the horse's @$&, I hold him there for a second before pulling him out and putting him down. The gnome shakes his head and says, 'maybe I should wefwaze that. Can I see her wun awound!' Embarrassed


HP
1 HP and the Half Blood Prince Cool
2 Kathleen Cool
3 July Cool
4 Daniel Radcliffe Cool
5 PG Cool
6 HP and the Chamber of Secrets Cool
7 a non-magical person. Cool So, for example, me. Shocked

Way to go Wizard. Razz




Who first gave the Greek letter "pi" its current mathematical definition?

• William Jones
• Archimedes
• Albert Einstein
• Max Planck
• Olle the Greatest




HP

8. Which school does Harry go to Question

9. What is Harry's friend Hermione's surname Question


10. How many Harry Potter books will there be in the whole series Question

6

7

10

42


11. Which publishing company publishes the Harry Potter books in hardback in the UK Question

12. Harry Potter's mortal enemy is the evil wizard Lord Question

13. J.K. Rowling was born on 31st July 19 Question Question

14. In what year was Harry Potter and the Philosopher's Stone first published in the UK Question

15. What is the name of Harry's house at school Question

Fin.
0 Replies
 
Liessa
 
  1  
Reply Sun 20 Feb, 2005 08:26 am
HP part 2

8 Hogwart's
9 Granger
10 7
11 Bloomsbury
12 Voldemort or You-know-who
13 65?
14 1997 - which makes it over seven years ago... Shouldn't Harry be graduating by now?
15 Gryffindor
0 Replies
 
Tryagain
 
  1  
Reply Mon 21 Feb, 2005 06:17 am
Liessa:

8 Hogwart's Cool
9 Granger Cool
10 7 Cool
11 Bloomsbury Cool
12 Voldemort or You-know-who Cool
13 65 Cool
14 1997 - which makes it over seven years ago... Shouldn't Harry be graduating by now? Cool Laughing
15 Gryffindor Cool

Liessa, you are a real wizard of HP. Laughing



Who first gave the Greek letter "pi" its current mathematical definition?
• William Jones


Although of little importance as a mathematician, William Jones is well known to historians of mathematics since he corresponded with many 17th Century mathematicians, including Newton. He was, however, elected a Fellow of the Royal Society in 1711.

Jones served at sea, teaching mathematics on board ship between 1695 and 1702. After his voyages were over he became a teacher of mathematics in London. He also held a number of posts in government offices.

Jones published Synopsis palmariorum mathesios in 1706, a book intended for beginners which included the differential calculus and infinite series. This book is also famed since the symbol p is used in it with its modern meaning.

Jones served on the Royal Society committee appointed to decide who had invented the infinitesimal calculus, Newton or Leibniz.
Navigation was also a topic which interested Jones and his first published work was A New Compendium of the Whole Art of Navigation. He applied mathematics to navigation studying methods to calculate position at sea.
In 1731 he published Discourses of the Natural Philosophy of the Elements.





In 1949, a digital computer was first used to calculate pi. To how many decimal places was this computer, ENIAC (Electronic Numerical Intergrator and Computer), able to find pi (it took 70 hours) Question

• 2037
• 10,493
• 576
• 297,454
• 8331





This lateral thinking problem appeared on a ?'Quiz TV' type programme.
(Reproduced exactly as it appeared on the screen)

Count all the "4's"

After 14 hours in the car Pedro
Foreman reached a fork in the
road. One way would take him
4 miles to his destination Ford
Forrest. Yet the other way would
take Pedro forty miles
somewhere else. The problem
was Pedro Foreman really
didn't know which way to go.

How many do you make it Question

(Yes, I do have the answer given by the winner)



All of Penny's pets are dogs except one. All of her pets are cats except one. How many cats and dogs does Penny have Question
0 Replies
 
Liessa
 
  1  
Reply Mon 21 Feb, 2005 06:51 am
HP: WOOHOO! now what was the title you wanted to give out? I'll put it in my sig :p

PENNY:
one dog, one cat...

4's:
either 2 or 8. 2 if you want the actual typographical 4's, 8 if you want the number of times the sound four is in the text.
0 Replies
 
DrewDad
 
  1  
Reply Mon 21 Feb, 2005 07:52 am
"4":
One, if you want the number of times the number four actually appears.
0 Replies
 
Tryagain
 
  1  
Reply Tue 22 Feb, 2005 06:14 am
HP: WOOHOO! now what was the title you wanted to give out?


Liessa, henceforth you shall be known as Princess Seladania Laughing

PENNY:
one dog, one cat... Cool


(Count all the "4's")

The winning answer was 24. I still cannot understand the logic. Can you make sense of it?



• 2037

The constant Pi, the ratio of the circumference of a circle to its diameter, is one of the most famous numbers in mathematics. For most persons the value of Pi is 22/7 or 3 1/7, or if greater accuracy is required 3.14159. A value of approximately 3 was known to the ancient Egyptians and Babylonians, and a value of exactly 3 may be inferred from a passage in the Old Testament. The calculation of Pi to an increasingly greater number of decimal places has fascinated, sometimes to the point of obsession, many persons almost since antiquity. For many years one of the best known calculations was that of the Englishman William Shanks who in 1873 calculated Pi to 707 places, of which only the first 527 were later proven to be correct.

In 1882 the German mathematician Ferdinand von Lindemann showed that Pi is transcendental and was not the root of a polynomial with rational coefficients. This showed conclusively the impossibility of squaring the circle, i.e., of finding the side of a square whose area is equal to that of a given circle, which was one of the three famous problems of antiquity. This result, together with the earlier proof in 1767 that Pi is irrational, discouraged much further work on computing the value of Pi until the ENIAC was used in 1949 to compute pi to 2037 places. Since then, Pi has been calculated to an ever-increasing number of decimals, the present record being 1.24 trillion places.



I was doodling the other day with four dots in a square, and wondered how many different ways there are of connecting all the dots.

Do you know how many there are Question




When Sidney Tone was suddenly murdered, Inspector Dirty Harry suspected Sid's wife Resa. Resa however, steadfastly maintained that on the evening of the murder she was dining in a restaurant with a relative.

Dirty Harry found an entry in Resa's diary for that evening which apparently confirmed her alibi as follows:

TIPS THE BRUSHED CHEFS.

However, Dirty Harry realized that the message was coded to reveal a startling confession. Where was Sid murdered Question

• The bathroom
• The kitchen
• The bedroom
• The garage
• The living room




Which of the following is the next entry in this series:

A, BB, CC, DD, E, F, G, H, II, JJ, K, LL, _______ Question
• MMM
• M
• MM
• MMMM
0 Replies
 
markr
 
  1  
Reply Tue 22 Feb, 2005 10:11 am
4 DOTS
Are you looking for the number of connected graphs? Are the points unlabeled so rotatiions/reflections don't count?
0 Replies
 
Tryagain
 
  1  
Reply Tue 22 Feb, 2005 03:32 pm
Mark, in answer to your questions, all I can add is, this was the second puzzle I saw, the words, "how many different ways" must be the clue.

If it helps, the answer given starts with a ?'4' and is less than 50. :wink:
0 Replies
 
Tryagain
 
  1  
Reply Wed 23 Feb, 2005 04:49 am
Two people are talking long distance on the phone. One is in an East-coast state of the United States. The other is in a West-coast state. The first asks the other "What time is it?", hears the answer, and says, "That's funny. It's the same time here!" What time is it Question

• 6:30 AM
• 11:30 AM
• 7:30 PM
• 1:30 AM
• 3:30 PM



How many times per day do the hour and minute hands of a clock form a right angle Question

• 40
• 42
• 44
• 46
• 48




Boston, New York, Philadelphia, Cleveland, _____, Atlanta, Chicago, St. Louis, Minneapolis, Kansas City, Dallas, San Francisco

Which city is missing from the list Question

• Los Angeles
• Orlando
• Detroit
• Richmond
• Portland
0 Replies
 
paulaj
 
  1  
Reply Wed 23 Feb, 2005 07:47 am
...
0 Replies
 
 

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