Challenge Definition and 911 Threads

This isn't a homework problem. I challenged myself to see if I could make this work... but I couldn't. Now I'm asking for help on it. The question is simple. \int \frac{W(x) W_1(x)}{x} \left(\frac{1}{W(x)+1} + \frac{1}{W_1(x)+1}\right) dx Now I have what this equals right here (W(x)...

I have been trying to plot a vector and it's derivative for a while now, but I cannot figure out why I can't get them to plot. Here is what I put for my code... a[t_] := Sin[t] Cos[2 t] b[t_] := Sin[t] Sin[2 t] c[t_] := Cos[t] V[t_] := {a, b, c} I tried this...

Hi Physics forums, I have been approached by an interesting challenge proposed by my colleagues. The goal is to build a structure completely out of newspaper with the longest span to support a 1500.0g weight at its centre point, duct tape allowed to connect ends. The point scheme is as...

Hi all! Good evening Here is the Question: This question is given as a challenge extra credit task, and is a part of a course called solid mechanics 2 that deals more with shear strain and strain matrices. While trying to translate the question I used the term "strength" instead of...

Homework Statement Let V a subset of the real line be called a vitali set if V contains precisely one point from each coset of the group of rational numbers. Prove: Homework Equations 1) every lebesgue measurable subset of V is a nullset. 2) V is not lebesgue measurable 3) every set of positive...

Homework Statement You are crossing a narrow bridge 1km long when you notice a truck approaching at 90km/h. If you can run at 5m/s, how far from the far end must you be if you could reach either end just before being hit by the truck? My attempt Displacement between the two...

Homework Statement Calculate the radius of convergence of \sum_{n=0}^\infty a_{n}^{2}z^{n} let \sum_{n=0}^\infty a_{n}z^{n}RADIUS R Homework Equations \limsup|a_n|^{\frac{1}{n}}=\limsup |\frac{a_{n+1}}{a_n}|The Attempt at a Solution the latex is killin me please help....

challenge question! whay does not monossacharides come less than three carbon atoms?? (I mean they just come triose to hexose)>>thnk you

Homework Statement So the goal is to reach a distance H in the x-direction, starting from a height H in the y-direction, and you need to minimize the speed, and find the smalest and angle. Homework Equations i did: dx = V cos(theta) *t and y = y_0 +V sin(theta)*t-1/2*g*t^2 Vx =...

Homework Statement Just when a Frisbee passes over the head of a student at a speed of 4m/s and decelerating at a rate of 1.5 m/s2, she starts to run accelerating at a rate of 1 m/s2. [neglect vertical motion of Frisbee] a)How long will it take the student to catch the Frisbee? b) If...

How would you solve this without using decisional blocks?

I just need a hint to solve the problem. The method used is illustrated in the example problem as follows: I am supposed to imitate the method used in the example problem to solve the challenge problem in the book as follows Imitate the method used in the last problem to find a formula...

Homework Statement sin(α+45) = ? The Attempt at a Solution Dunno. Really dont. Need it in simplification.

Homework Statement Solve the following parametric equations for y = f(x) x(t) = e^{-t} + t y(t) = e^{t} - t The Attempt at a Solution I'm completely stuck on this one. I've noticed x + y = e^{-t} + e^{t} and also y = \frac{1}{x-t} - t but that's about as far as I've gotten.

Does the fact that a car burns fuel to keep it moving mean that we can truly say that the car is moving and not the earth? If so does this disprove the 1st postulate that maintains ALL uniform motion is relative? *I know that objects in space don't require fuel to move at a constant speed...

Okay, I am totally baffled here. For our final project in Algebra we have one class period to build an egg drop carrier. The egg will be dropped from 8 feet, and we have VERY LIMITED materials. - 8 Straws - 1 6x6 Piece of Thick Paper - 3 Tissues - 2 ft. of Masking Tape Another rule is that...

Dear readers, At my webpage: http://domingogomez.web.officelive.com/brocotfraction.aspx I have posed a challenge entitled "To PI or not to PI", it deals with a generalized continued fraction (bifurcated fraction) whose coeficients are all the Stern-Brocot fractions, that is, all...

Homework Statement A flexible, circular conducting loop of radius 0.15m and resistance 4 ohms lies in a uniform magnetic field of .25 T. the loop is pulled on opposite sides by equal forces and stretched until its enclosed area is essentially zero m^2. it takes .30s to close the loop. what...

Homework Statement find \int\int_D sin\left(\frac{y}{x}\right)dA bounded by x=0, y=\pi, x=y^2The Attempt at a Solution I've only studied calculus 1, this problem is for my friend. I did read up briefly on double integrals however and this is why I'm stuck: From the limits and where the graphs...

I have teenaged daughters, and like many of their peers, they're obsessed with their body weight. Unfortunately, since I have access to accurate scales at my gym, I've never bothered buying a bathroom scale at home, and this is now becoming a source of friction. Rather than simply surrender...

Right now we show that we have 197,293 PFers. Do we have any guesses as to the date and time that we hit the 200,000 mark?

I've been working on this for years; self determination; there IS a time to say "Help"; this is it. Equations of motion; I'm well acquainted with them, but THIS one is unique, and I can't get to first base. V is Velocity X is distance/location t is time X = 4*(t^2) - 15 - K*V so I...

Homework Statement A particle of mass 1kg is projected in XYZ space, where Gravity (g=10m/s2) acts in -\hat{k} direction. The initial velocity of a particle is \vec{u}=(-3\hat{i}+4\hat{j})m/s. x-component of acceleration = 3t/4 y-component of acceleration = -1 - 3t/4 If total work done in...

A real challenge to all physicsist! In order to experience free fall a student walks off the top of the CN Tower which is 553m high and falls freely. His initial velocity is zero. The rocketeer arrives at the scene 5 seconds later and dives off the top of the tower to save the student. The...

..sucks. I have the Sky-Watcher 10" dob (got it for xmas). All around, it's a great scope for the cost, and produces some very crisp visuals of surprisingly distant objects... when it can center on them. I find myself having to constantly aim higher than the object so my telescope will "fall"...

Okay so we are going to drop an egg from three stories high. The only materials we are allowed to use is popsicle sticks, glue, string, and garbage bags...HELP!

I found on wikipedia that the following statements are equivalant: 1. Matrix A is left invertible 2. Ax=0 => x=0 I couldn't find the proof so I try to do it myself. From 1. to 2. is easy. Assume A is left invertible. If Ax=0, then x=Ix=A-1Ax=A-10 = 0 . I can't figure out how to do 2=>1. Any...

Homework Statement Every 2km power is reduced by half. Initial power = 10watt. What is power after traveled 8km? C = 3x108. What is speed of light passing through optic fibre? n = 1.55Homework Equations P = \frac{w}{T} ? The Attempt at a Solution I don't know where to start

Homework Statement So I'm trying to find the integral of P = 2xyz^2 along the curve c which is defined by: x=t^2 y=2t z=t^3 t goes from 0 to 1 So the q says that it is the integral of P dr along c Homework Equations The Attempt at a Solution So I know that this...

Mouse trap car! i need to make a mouse trap car that goes 7 meters forward and then goes 7 meters back.

I have a challenge for anyone gifted enough to communicate with a stupid layman in terms that I can understand. I'm struggling in my attempt to understand the concept of "spin" with regard to fundamental particles. 1.) How can a fundamental particle that has no spatial dimension have an axis...

My cousin challenges me with a tough limit problem. Compute the limit as x->0 of (sin(tanx)-tan(sinx))/(arcsin(arctanx)-arctan(arcsinx)). This limit seems impossible to do. I used L'Hopital's rule but it didn't help at all. Can anyone find a way to do it?

Prove that: F_{n} = \frac {\varphi^n - (1-\varphi)^n}{\sqrt5} holds true for any number in the Fibonacci Sequence. Who can answer the fastest?

Prove that this is the equation of a straight line; -\frac{\zeta(x)\zeta(2)y\Gamma(x)}{\int_0^\infty \frac{u^{x - 1}}{e^u - 1} du \int_0^1 \frac{\ln(1 - x)}{x} dx} - \nabla \cdot (\nabla \times \vec{A}) = \frac{L^{-1}[\frac{F(t)}{t}] \int_{k = 0}^1 \int_{\theta = 0}^{\pi /2} \frac{d\theta...

Hello, With regards to a Youtube video- Spin polarized tunneling - video #10: , could some one familiar with electronics provide a circuit or diagram for this to work? Also what type & size of barrier could be used? This should be fairly easy for anyone familiar with electronics, so any help...

Homework Statement The problem is If x= 2+2 2/3 +2 1/3 solve x 3-6x 2+ 6x-2 =0 Homework Equations The Attempt at a Solution First i tried to substitute the values but its turning out to be really big( and i get quite scared when it turns up like this and so i didn't go any further...

NEEDD HELP! parameterizing a surface given by an implicit function (HYPERBOLOID?!) Homework Statement I need to parameterize the surface given by the following implicit equation: x2 + y2 + z2 + 2xy + 2xz - 2yz = 1 Homework Equations I tried using all sorts of subsititutions...

This isn't a homework question or anything, but I came across this challenge problem posted on a Harvard Math 25a webpage and I'm wondering what the solution to it is since no solution is posted on the page. Suppose that f\colon \mathbb{Q} \to \mathbb{Q} satisfies f'(x) = f(x) for all x \in...

Homework Statement Determine the force P required to like the 200kg crate. Coeff. Static friciton is 0.3 on ALL contact of surfaces. Neglect Wedge Mass Homework Equations μS x Fn = Fk Summation of forces eqns The Attempt at a Solution im getting more unknowns than equations see attachment.

Solid Mechanics questions - A new challenge :) Hi all :wink: I got 3 new questions that need to be solved in about 3-4 days as part of a 'challenge' homework. Those who solve correctly will basically get their names read out loud on the next lecture but I do it to understand the material of...

Homework Statement Two moons orbit a planet in nearly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 5r. Moon A takes 50 days to complete one orbit. How long does it take moon B to complete and orbit? Homework Equations Kepler's Third Law The...

hi everyone ! we have two circles that doesn't have intersections now we want to find a point on each circle that the distance of this two points are 'k' please help me . . .

hi :] i have a surprise for anyone who can solve my challenge: we have the korona voltage formula... http://img130.imageshack.us/img130/4859/aaae.jpg" let's see who can give me the long way to it (from beginning to end and can explain it).. since it's the final formula.. only 3...

I'm currently trying to write a report at the moment with some tables for some data, and it would be ideal for me to put these tables side-by-side if possible. However, I'm not sure as to how this can be achieved; I've currently doing \documentclass{article} with multiple figures of graphs...

Hey. Im currently doing a course in numerical analysis, and while most of the focus is on the mathematics side of things, the assignments are set in an engineering context. One of my assignments describes a beam that is "pin jointed" at both ends, is 1 meter long, and is subject to a 0.5 N/m...

Sled Dogs work? A team of dogs drags a 46.5 kg sled 1.73 km over a horizontal surface at a constant speed. The coefficient of friction between the sled and the snow is 0.233. The acceleration of gravity is 9.8 m/s2 . Find the work done by the dogs. Answer in units of kJ [b]2. W=Fd F=mg...

Can you give me a suggestion how to find a reasonable algorithm do distribute undividable goods among different people? All of the people have different preferences, but might be clashing. Also some of them might have priorities, due to not getting anything last round. So for one round there...

Pi. An infinite number. INFINITE. People have been memorizing the digits of pi to a certain number of decimal places. A challenge for you: how many can YOU remember? I hold the world age record(i actually don't, because i haven't told anyone except my friends about it) for memorizing 1500...

Insane Electromagnetic Induction Question. Challenge your brains! :D F=BIL, F=mg There is a B field acting on the rod so we resolve that. I tried to resolve the other force vectors according to: 1. Force acting on rod by gravity 2. Force acting on rod by electromagnetic (F=...

Greatest challenge for science-- Reincarnation! I don't know about other European countries but Here in south-east-Asian country, more definitely, India and Nepal, We have a bunch of stories regarding re-incarnation or rebirth. There are lots of evidence that a boy/girl only 3 or 4 years old...