Puzzle Definition and 618 Threads

Hi - following an example in my book to calc. the Fourier Transform of the Gaussian. We need to complete the square to integrate the exponent, the power is $-a^2t^2+i\omega t$ ... - all good so far. Trouble is when I complete the square I get -a^2(t-\frac{i\omega}{2a^2})^2...

I remember back at physics A level we were posed with the question of what happens when a train hits a fly. According to Newton laws the forces are equal, and so, by this theory, the fly should stop the train. We obviously knew that this didn't happen, but it took the whole class waaay too long...

I was just sent an email with the following text. "" Here is a puzzle I just encountered. Take any NPN transistor and ground the base. Now apply +12 volts to the emitter through a series resistor of 1k. Yes, it is a Zener diode of about 6 volts so about 6 ma of current flows.What is the...

Founding this : http://arxiv.org/abs/1502.05314 if I understood correctly the radius of the proton is smaller using muons instead of electrons. Could this be due to the fact that the gravitation force becomes repulsive at small distances so that the particles are kind of compressed by it ? I...

HI all How can Michelson itself predicted contraction of length and Einstein about constancy of light from negative result of MM experiment. forget about existence of ether, light speed always same in moving frame of reference and importantly in any direction so how can one except shift in...

Homework Statement A man that has an ordinarily weight of 780 N stands on a libra on the equator. Homework Equations What is the weight measured by the libra? The Attempt at a Solution I thought it was simple, so I just did: P = m * g Since it gives me P I can simply do: m = P / g = 780 /...

So we all know that due to the conservation of volume flow rate, reducing the diameter of a hose pipe would increase the velocity of the water flow.(A*V is conserved) But when the are of an orifice near the bottom of a water tank is reduced the velocity remains the same! Does anyone know why...

I've been staring at this for hours but I do not get how the pattern works at all. The problem is from this website. It's not that I'm an idiot, I think there's something wrong with the pattern!

I came across this new programming puzzle game on steam. http://www.zachtronics.com/tis-100/ The constraints of the machine make for some interesting programming puzzles. You get a grid of nodes. Each node can execute 10 or so really basic instructions (MOV, ADD, SUB, JMP, SAVE, SWAP). You...

I see an example from book stated that a muon that are created at high altitudes can travel to the ground because of time dilation about its lifetime. In the view of muon, it travels shorter distance compared with the view of the Earth. Suppose there are two muons. In view of muon A, muon B is...

Anyone like riddles? I've got funny one. ​The Math Riddle Question: Where is the koala? There are five houses, each of a different color and inhabited by men from different territories, with one unique animal*, drink, and car. Some facts are given: 1. The Tasmanian lives in the red house. 2...

Imagine an uncharged solid spherical conductor. Inside this spherical conductor, there is a cavity of a weird shape carved out of it. And somewhere inside this cavity, there is a charge +q. The charge +q induces an opposite charge -q on the wall of the cavity of the conductor, which distributes...

This is a puzzle I came up with. I'm trying to judge whether the solution is obvious or not. Technically it's more closely related to quantum computation than quantum physics, but... let's try it anyways. We find ourselves with the following network: The goal is to find a way for the sender...

Suppose 3 1D Signals x(t), y1(t) and y2(t) are given as x(t)=sin(40*pi*t); y1(t)=.5*sin(40*pi*t) and y2(t)=x(t)+y1(t). Left side =Right side Here,values of x(t)and y1(t)i.e.(Right side) are given and we get y2(t)(Left side).The plots of x(t),y1(t) and y2(t) are plotted below...

I just show how .999... = 1 Let x = .999... 10x = 9.999... 10x - x = 9.999... - .999... 9x = 9 x=1 So according to the above .3333... shows as 3. Let x = .3333... 10x = 3.333... 10x - x = 3.333... - .333... 9x = 3 x=3 But according to me, .333... should equal to .4 , isn't it? I must be...

First of all, this is NOT a homework question. So I give you three barrels, one has 50 apples, the second has 50 oranges, the third has 50 - a mixture of both apples and oranges. However, I have intentionally placed the wrong labels on all of them. Find the minimum number of fruits you need...

Homework Statement I need help with egg drop ideas! For this project, I have to create something that will catch an egg (about 62.5 g) dropped from a height of 9.91 meters so that it will not break or crack. I also have to discuss forces, impulses, momentum, time and velocity changes of the...

Hi, I'm doing some programming work with regards to this puzzle. Impossible Puzzle - Wikipedia, the free encyclopedia I have to generating the solutions to the the resulting solutions after the four following sentences are said. P says "I cannot find these numbers." S says "I was sure that...

Homework Statement [/B] Impliment the expression which is already in minimum sum of products form using only two-input NAND gates. No gate may be used as a NOT. All inputs are available both uncomplemented and complemented. (The number of gates required is shown in parentheses.) f = ab'd' +...

Homework Statement One hundred bushels of grain are to be distrubuted amongst 100 people. Each man gets 3 bushels, each woman gets 2 bushels, and each child gets 1/2 bushels. How many men, women and children are there? Homework Equations GCD, euclidean algorithm, Diophantine equation The...

Hi, I'm trying to prove something that I think is simple but am really struggling so would greatly appreciate any help! Over 2 weeks I receive rebates, the value of the rebate can vary both due to the rebate on each case and also the number of cases ordered. Between week 25 and week 26 my...

Homework Statement A block of mass m is attached to a spring of spring constant k. It lies on a floor with coefficient of friction μ. The spring is stretched by a length a and released. Find how many oscillations it takes for the block to come to rest. Homework Equations d2x/dt2 + k/m x = +_...

I finished my online E&M class today, and the prof told us to experiment with polarizers. While doing that, I found this: I put a piece of plastic between two polarizers, and found that at a certain angle between the two polarizers, a portion - though not all - of the plastic darkened. So I...

So I've been trying to do some physics puzzles and I've come across this in a book called "200 puzzling physics problems." The solution in the back makes no sense to me and I can't seem to figure it out by myself. Can anyone help me?

My problem is described in the animation that I posted on Youtube: For the sake of convenience I am copying here the text that follows the animation: I have made this animation in order to present my little puzzle with the quantum harmonic oscillator. Think about a classical oscillator, a...

You walk into an elevator, step on a scale, and push the "up" button. You recall that your normal weight is 625N. If the elevator has an acceleration of magnitude 2.50 m/s^2, what does the scale read? I know how to solve this problem, but I don't know why I'm getting the wrong answer. I first...

Homework Statement A total charge of 50 Ah is stored in a 12 V battery of a car. Each of the bulbs of the four parking lights is labelled 3,6 W / 12 V. Homework Equations a) Find the current from the battery when only the parking lights are switched on. b) What is the resistance of one bulb...

I was asked to look at a problem (not homework) in which a tangent ellipse is to be found for a circle. This puzzle is turning out to be more than I bargained for. See the attached image because hey, a picture's worth a thousand words. The givens in this problem are to be the radius ##R_i## of...

My daughter needs my help, and I am stumped. Here is the problem: In the first round of the city soccer tournament, the teams in group A finished as follows: Team------>Goals For------>Goals Against----->Points Naranja---> 4--------------->2-------------------->7 Bleu------>...

1. In a 3 x 3 square, place the numbers 2,2,2,3,3,3,4,4,4 in it so that when any line of three numbers is added up in any direction (including diagonally) the total is always 9. 2. I have tried for hours, can anyone tell me if this problem is actually possible? The best I get is when I do 234...

The position function for a particle moving on a circle (with constant speed) is: ## \vec{r}(t)=\left \langle r\,sin(t), \, r\,cos(t) \right \rangle ## Taking the first and second derivatives, ## \vec{v}(t)=\left \langle -r\,cos(t), \, r\,sin(t) \right \rangle ## ## \vec{a}(t)=\left \langle...

Pretend you own a printing press and you want to be able to represent any arbitrarily large natural number. You also want to store the fewest possible number of characters in your collection, just to save space. What base, if any, would yield the largest ratio of numbers you can represent to...

Homework Statement The problem is given in the attached file. Homework Equations Divergence theorem, flux / surface integral The Attempt at a Solution [/B] As you can see I got the question correct using Divergence theorem. But I wanted to make sure that I could arrive at the same answer...

Write a loop that sets newScores to oldScores shifted once left, with element 0 copied to the end. Ex: If oldScores = {10, 20, 30, 40}, then newScores = {20, 30, 40, 10}. Sample program: #include <iostream> #include <vector> using namespace std; int main() { const int SCORES_SIZE = 4...

If 28+453+9012=81.534 91+712+1024=49.091 Then 66+935+1389=?

Hey all, I'm new here and thought I'd introduce myself by providing you with a nice puzzle to solve. Answers to be sent with reasons! LePuzzled1

In General Relativity spacetime is described by a metric. The most common one is the Schwarzschild metric, valid at radii greater than the surface radius of a mass. If we assume constant angular position so that dθ=dø=0, then this metric relates local (proper) coordinate time and distance dτ...

Two spaceships approach an observer from an equal distance and from an opposite direction with an equal speed in the observer's intertial reference frame O. The speed of a spaceship in the intertial reference frame of the other spaceship S is 0.8c , what is the speed of one of the spaceships in...

Hello This is question is bugging me for years. Why is division by 0 undefined and not multiplication by 0 undefined? If any number multiplied by 0 is 0 then the logical answer for any number divided by 0 would be ∞ (for me at least). If you "define" N/0=∞ and N*0=undefined then there are...

a = x^2 + 2cx + 1 b = 2x + 3c + 3 a / b = 5 plus a remainder of 11. c=? Want to include above in a "puzzle" site. Want see if it makes sense.. Can you solve it? Than you.

If you have one 4 liter container and one 3 liter container how do you measure 2 liter of milk by using them? Please explain in detail

Am I getting dumb for some reason or is this a good puzzle? PF friends! What am I missing here? Really, from where did that empty block come...

I was debating putting this up in General Physics, but since I already know the answer, I thought I'd put it here. I also put this in some other places to see how different forums would react - my own little experiment. =========== A true story: I once took a car GPS with me on an airplane...

So person A takes 1 less hour than person B to mow a lawn, Person C takes twice as long as Person B to mow a lawn. All together they mow a lawn in one hour. How long does it take each of them to mow a lawn working alone? Can someone explain this to me please, thanks.

Homework Statement Hi so I have a problem that I don't exactly know how to approach, here's the diagram: http://images.fr1ckfr4ck.fastmail.fm/probA.jpg The diodes are supposed to have saturation current I_s = 10^(-15) A Homework Equations What is V? The Attempt at a Solution First I tried...

Hi~ I recently solve a Laplace transform problem as following L[int{t,0}cosh(t'-1)U(t'-1)dt']=? U(t'-1) is the unit step function(=1 for t'>1, =zero otherwise) According the standard Laplace formula : (1)L[cosh(t-1)U(t-1)]=exp(-s)*s/(s^2-1); (2)L(int{t,0}f(t')dt')=F(s)/s...

Hello everyone. I am trying to complete a programming challenge, of which I have taken a screenshot of and posted on flikr. I was wondering if there was some math genius on here who could help me solve the puzzle. Forget about the programming part, I can do that. All I need is some advice on...

This is driving me nuts. What am I missing? Suppose you have an inclined plane with a mass m resting on it. The free body diagram for the mass m has F_grav downward and F_normal perpendicular to the surface of the inclined plane. Thus, by Newton's Second Law, you have: ∑F=F_grav+F_norm=ma with...

Homework Statement Find the voltage Vo using node voltage method specifically.Homework Equations The Attempt at a Solution I am able to get the correct answer when finding the equivalent impedance, then determining the current, and then finding the voltage at the first node V1 by subtrating...