Distribution Definition and 1000 Threads

The think is that I would like to create a magnetic trap "minimum of magnetic potential energy in all 3 directions of space" using a distribution of magnetic dipoles as a field generator. In other words, I would like to know if setting in some way some magnetic dipoles is possible to create a...

Homework Statement The random variable X is normally distributed. The values 650 and 850 are at the 60th and 90th percentile of the distribution of X respectively. Find the value of the 75th percentile of the distribution of X. Homework Equations I found the above formula from internet. where...

Hello, I have been thinking about this problem for a while, but I can't decide how it should be tackled statistically. I wonder if you can help, please. Suppose that prostheses for hip replacement are sold mainly by 2 manufacturers, A and B. Since they started being sold 20 years ago, 100 000...

Homework Statement Consider a model thermodynamic assembly in which the allowed (nondegenerate) states have energies 0, ε, 2ε, 3ε.The assembly has four distinguishable (localized) particles and a total energy U = 6ε. Tabulate the nine possible distributions of the four particles among the...

<< Mentor Note -- Thread moved from the technical forums so no Homework Help Template is shown >>[/color] I'm particle physics at the moment and I don't get why the average value of cosˆ2 is 1/3. The section : My solution is : < cos^{2}(\alpha)> = \frac{1}{\pi - 0} \int_{0}^{\pi }...

Homework Statement Hello, this is more of a conceptual question than a concrete homework assignment question. I'm learning about Gauss's law and the Prof did an exercise on a sphere with uniform charge distribution, where he found E(r). The trick was, that E(r) was constant over the Gaussian...

Hello, I am relatively new to Python. I would really like to use Python for numerical and data analysis. I recently stumbled upon something called Intel Distribution from this article: http://www.infoworld.com/article/3117239/data-science/intels-python-distribution-turbocharges-data-science.html...

Hi everyone I'm having trouble with solving an exercise in statistical physics. I need to argue why the average number of particles with a velocity between ##v## and ##v+dv## that hit a surface area ##A## on the container wall in a time interval ##\Delta t## is $$N_{collision}=v_{x}A\Delta t...

I am currently enrolled in a statistics course, and the following is stated in my course book with no attempt at an explanation: Suppose that f is the probability density function for the random variable (X,Y), and that F is the distribution function. Then, f_{X,Y}(x,y)=\frac{\partial^{2}...

Homework Statement In a certain region, the electric potential due to a charge distribution is given by the equation V (x, y, z) = (3x2y2+yz3-2z3x)V0/a4 where a, x, y, and z are measured in meters and V and V0 are in volts. What is the magnitude of the electric field at the position (x, y, z)...

What is the current habitat range of Turritopsis dohrnii or the "immortal" jellyfish? I know that there are multiple species of the Turritopsis genus and that the species dohrnii have recently increased its range by ballast water spread. What is the current range of the exact species dohrnii?

hi, I am looking for a proof of weibull distribution, I have searched a lot but nothing is reasonable for the proof, so ıs there derivation of this distribution ? What is the origin of this distribution ?

Hi all, Can anyone teach me this problem ? Thanks The life of a tiger is exponentially distributed with a mean of 15 years.If a tiger is 10 years old, what is the expected remaining life of the tiger? A 5 years B 10 years C 15 years D Longer than 15 years

Rather than going off topic in a thread about inviscid fluid in a pipe, I decided to start a new thread. For this thread, I'm wondering about the effect of a ducted propeller operating in the air. Using this NASA article as a guide: https://www.grc.nasa.gov/WWW/K-12/airplane/propanl.html The...

Suppose that cars pass a certain intersection at a rate of 30 miles per hour. What is the probability that during a three-minute interval, no cars will pass the intersection? I am really just wondering which distribution to use. I thought is should be Poisson because it is asking for events...

Hello forum, I'm hoping i can get some help figuring something out. I'm working on a project which requires a 4 wheel trolley frame to be designed to transport cargo. The basic dimensions of the trolley I've already determined based on the required need and ergonomic guidelines etc. Now i need...

Homework Statement Homework Equations [/B] Definition: A sequence X_1,X_2,\dots of real-valued random variables is said to converge in distribution to a random variable X if \lim_{n\rightarrow \infty}F_{n}(x)=F(x) for all x\in\mathbb{R} at which F is continuous. Here F_n, F are the...

The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 1263 chips and a standard deviation of 117chips. ​(a) Determine the 26th percentile for the number of chocolate chips in a bag. ​(b) Determine the number of chocolate chips in...

Homework Statement The X-ray intensity distribution function for an X-ray lamp is given on the figure. What is the maximum velocity of the electrons? What is the potential difference under which the lamp is operating? Figure: http://imgur.com/01kCBc8 Homework Equations Kmax = 0.5m(vmax)^2...

My understanding of the distribution curves is very basic but I do have a couple of somewhat generic questions. I looked up a number of definitions but have had a hard time finding these specific answers: - Is there an agreed on minimum number of samples that one needs to take to deem a result...

I was thinking about the "distribution" of a particle in space in different situations. An electron bound in a atom have a wave function that is broad. What about the broadness of the wave function of conduction electrons in a wire? Or doesn't it even make sense to quantum-mechanicaly speak of...

Given this libreoffice command: HYPGEOM.DIST(X; NSample; Successes; NPopulation; Cumulative) >X is the number of results achieved in the random sample. >NSample is the size of the random sample. >Successes is the number of possible results in the total population. >NPopulation is the size...

Homework Statement I don't understand why for the first case , the 0.4 and 0.6 is used ? for the second question , we can see that in the first case , the moment from BC is carried over to CB ( highlighted part - line 4 ) ... Why for the second case , the moment from BC (6325.8) isn't carried...

Hi. How is three-phase electric power distributed in a household with mainly single-phase power plugs? Do they just connect a phase at random to every plug? As far as I understood, it's best if all three phases deliver the same current, since then neutral cancels. Do electricians take into...

Dear friends How can i calculate RDF(radial distribution function)? Thanks

Homework Statement Show that the FD distribution can be viewed as giving the probability that a given state ( of the prescribed energy) is occupied. Homework EquationsThe Attempt at a Solution Solution to this problem: I understand the solution,but I took a different approach...

Homework Statement An electron has two spin states and a set of energy levels E1,E2,... By the Fermi-dirac distrbution,the mean number of electrons in energy level Ek is https://en.wikipedia.org/wiki/Fermi–Dirac_statistics#Distribution_of_particles_over_energy Does it mean that,for an electron...

The colloquial statistical mechanics explanation of entropy as if it is caused by probability is dissatisfying to me, in part because it allows highly organized (i.e. with a real potential for work) arrangements to appear as 'random fluctuations', though with very low probability. But as far as...

Homework Statement Two components of a laptop computer have the following joint probability density function for their useful lifetimes X and Y (in years): f(xy)=xe^(−x(1+y)) 0 <= x <= y 0 otherwise Find the marginal probability density function of X, fX(x). Enter a formula below. Use * for...

Homework Statement A metallic sphere of radius a is placed concentrically with a metallic spherical shell with inner radius b and outer radius c. The sphere has a total charge of 2Q and the shell has a total charge of 3Q. (a) What is the charge distribution? Specifically, what is...

I am using fastjet in pythia8.I am studying jet formation in pp collisions.I need to plot distribution of transverse momentum of fastest particle in fastest jet formed in 1000 events simulated.But i don't know how to access particle properties after jet formation.Like if I want to know the...

Homework Statement From differentiating Planck's distribution and setting it equal to 0 I've reached the equation below. But now I'm asked to estimate the solution for a/λ. It's suggested that we try to do it graphically/trial and error as it's tricky to do analytically. I'm wondering how I...

Homework Statement Charge Q is uniformly distributed along a thin, flexible rod of length L. The rod is then bent into the semicircle shown in the figure (Figure 1) . Find an expression for the electric field E⃗ at the center of the semicircle. Hint: A small piece of arc length Δs spans a...

I am unable to find a paper on this only the abstract, but it seems to be saying that there is no Dark Matter? The tightness of this relation is difficult to understand in terms of dark matter as it's currently understood, the researchers said. It also challenges the current understanding of...

Homework Statement Homework Equations Gauss The Attempt at a Solution I am really confused with question a, I have an idea of how to answer b and c once I obtain an answer for part a... My best guess would be to use Gauss, but I am not sure. Would the field inside be 0? What will the bounds...

My end goal is to extrapolate observed intelligences in the animal kingdom to determine whether or not it is statistically likely that a simulation argument is probable (though this could easily be used for the Fermi Paradox as well). Defining terms: "intelligence." Obviously all animals would...

I have a 2x4 on it's edge that spans 10 feet in my ceiling. I want to hang a swing that can hold 250 pounds near the center of this span. What would I need to do in this situation in order to get minimal or no deflection?

In kinetic theory, the number of molecules hitting a unit area of a surface per unit time with speeds between v and v + dv and angles between \theta and \theta + d \theta is found to be a function of sin(theta) and cos(theta). There will often be a practice problem asking to show that the...

Homework Statement A car is on a ramp of angle theta with the horizontal with the front of the car pointing up the ramp. Its weight distribution is uneven so that more of its weight is towards the rear of the car therefore the center of mass is closer to the rear of the car. The car is very...

Homework Statement In a company, out of a sample of 20 bulbs, the mean number of defective bulbs are 2. Out of 1000 such samples, how many samples would have atleast 3 defective bulbs? Homework Equations Mean = n * p where n is number of bulbs and p is probability of a bulb being defective...

Homework Statement Can someone explain why f(x) = 1/(b-a) for a<x<b ? Homework EquationsThe Attempt at a Solution shouldn't it be 0? since its a continuous random variable and so that interval from a to b has an infinite number of possible values?

This thread is prompted by a closed thread which left it’s OP’s original question unanswered. ->https://www.physicsforums.com/threads/average-wavelength-for-blackbody-radiation.423536/ The original question asked: is the ratio, of (a) the wavelength corresponding to the average energy in the...

So let's say I do some measurements and obtain a set of measured values. The measurement is characterized by random errors so by making enough measurements, they approach a normal distribution. In other words, my set of measured values can be approximated by a normal distribution characterized...

Hello everyone, I am working on a project in astrophysics in which I need to include now some type of particle distribution (as a function of the radius). I was wondering if there is some accepted function that would describe the number of particles per radius in astrophysics. Saturn's rings...

Homework Statement For the circled part , i don't understand why it's 4 and 6 . I know that it's about distribute the moment according to the ratio that we have determined earlier . Homework EquationsThe Attempt at a Solution For 4 , shouldn't it be 240*0.4 = 96 ? For 6 , shouldn't it be...

Homework Statement Initially there is a spherical charge distribution of with a radius ##R_0## and uniform charge density ##ρ_0##. Suppose the distribution expands spherically symmetrically such that its radius at time t is ##R_0 + V t##, where V is the velocity. Assuming the density remain...

When computing the probability distribution of bosons, why is A = 1 for photons? Does this not imply that photons will have an increasingly high probability of being present as E approaches 0? What is the significance of such a situation?

Hey! :o I am looking at the following: The average tallest men live in Netherlands and Montenegro mit $1.83$m=$183$cm. The average shortest men live in Indonesia mit $1.58$m=$158$cm. The standard deviation of the height in Netherlands/Montenegro is $9.7$cm and in Indonesia it is $7.8$cm...

Diffusion of gases seems to follow normal distribution. I imagine deviations from the mean would depend on temperature, mean free path and speed of gas molecules. Any other? Cheers, Glenn

What does the distribution curve of IQ in the world population look like? If the average IQ for all countries is 90 (Richard Lynn and Tatu Vanhanen “IQ and the Wealth of Nations”), with an average IQ for sub-Saharan Africans of 70, I suppose that the distribution curve is higher on the downside...