Puzzle Definition and 618 Threads

I do not know how to do the second part of this question. I never learned this. A laser used to weld detached retinas puts out pulses of 640 nm light, 25 ms long, which average 0.50 W output during a pulse. i) how much energy can be deposited pre pulse? ii) If the energy of a light...

this is my webassign question for this week but I'm a little confused about the first part... for part a) shouldn't the ratio just be 1 to 1, since the piston is exactly in the center?? or did i understand that wrong? I'm not all that great at chem especially when it comes to chem and physics...

Hi, its my first post, so don't be too hard on me. Here's my dilemma: I'm trying to write a computer program, to return a number with it's apropriate suffix. (ie: 1=1st, 2=2nd, 3=3rd, etc.) Forget the programming aspect for a minute, all I'm interested in is the logic. If X=answer, I can...

Can anyone solve this puzzle that a friend sent to me? When Ann is half as old as Mary will be when Mary is three times as old as Mary is now. Mary will be five times as old as Ann is now. Neither Ann nor Mary may vote. How old is Ann?

It's been bugging me http://goth1337.tripod.com/puzzle.tga

How can there be dust on the moon if there is no weathering whatsoever? I'm going insane over it.

Problem: (n!)^3 n = {1-99} How many digit is the resulting (n!)^3 ? Attempted solution: \Sigma^{99}_{n=1} (n!)^3 = (\Sigma^{99}_{n=1} (n!))^3 = 99(\frac{1!^3 - 99!^3}{2}) =~ 470 digits. But they say it's wrong. Please help.

I have a huge jigsaw puzzle to assemble. I start by looking through the pieces and see if there are pairs I can join. Then, I look through the pairs and see what other pieces I can add on. The size of my assembled pieces grows and their number shrinks. I am using the algorithmic paradigm called...

Consider the following: You are in a room containing an 3 empty metal bottles. Each bottle is equipped with a valve which when open connects the interior of the bottle to the room, and when shut seals the bottle. You also have a pump that can generate an air pressure of 10 Pascals. It...

Mad Ade was looking after his two year old Nephew (He charges two Kebabs an hour if you are in need of a babysitter). His Nephew had 4 play blocks each with 6 sides. Each side has a letter from the alphabet. No letters are ever repeated. By arranging the blocks in different ways Mad Ade's...

In Ireland, 16 year olds are expected to answer this question at some point during the leaving cert physics course. I’m finding it difficult to answer. Can anyone help me here? Ah, nothing like sharing wisdom... The rear of a bicycle passes a point P on a road and travels at a steady speed of...

This one I read but is so good I wanted to post it reworded. Two groups of people live on this planet, pure liars and pure truth tellers. I went to a philosophy party(never mind that it's impossible) and met 3 people. The first says something but I don't catch it, the second one replies, "he...

Okay Maths quiz! normal rules apply (first to answer question correctly gets to ask the next question, etc.): 1) √(5 + √(24)) = ? in exact surd form

Noting their locations I place two aces and a jack face down on a table in a row. You do not see which card is placed where. Your problem is to point to one of the cards and ask me a sinlge yes or no question, from the answer to which you can, with certainty, identify one of the three cards as...

hi! I've got a puzzle.can u solve it?here it is: a father has 90 apples.he has 3 children: A,B,and C.one day, the father told his children this: Come here A, sell this 50 apples with the same procedure like your 2 brothers that result the same income Come here B, sell this 30 apples with...

"hardest puzzle ever" today i ran across this puzzle: -------------------- ON a train Smith, Jones, and Robinson are the fireman, brakeman, and engineer, but NOT respectivly. Also aboard are three business men who have the same names: a Mr. Smith, a Mr. Jones, and a Mr. Robinson...

What is the greatest Mathematical puzzle that is unsolved? and why?

one needs to estimate or calculate how many cellular phones can fill the front seat's leg room of a BMW Z4 (Only the leg room of both the front seats and not on the seats)- a range of Samsung handsets are filled up to the seat level only, I believe their is a scientific way of determining...