Periodic Definition and 411 Threads

has anyone ever memorized the periodic table?

Homework Statement Show cos²(x) is periodic The Attempt at a Solution I don't know how :confused:, could somebody please show me step by step? Thanks in advance! edit: I've got another show/justify question. If f is an odd function, then show f of f is an odd function. Whilst I...

i have two questions from kleppner's book, here it goes (iv'e attached a file which have the sketchs of the two problems): 6.17 A rod of length l and mass m, pivoted at one end, is held by a spring at its midpoint and a spring at its far end, both pulling in opposite directions. The springs...

Homework Statement Suppose f(t) is a periodic function with period T. Show that the Laplace transform of f is: L(f) = \frac{1}{1-e^{-sT}}\int_0^T f(t)e^{-st} dtThe Attempt at a Solution I started with the definition of a Laplace Transform for f: L(f) = \int_0^\infty f(t)e^{-st}dt Using the...

Hello I am stuck on the following question: Consider the following graph of a periodic function, period T. http://img157.imageshack.us/img157/4337/waveme4.png (a) Clearly giving the reasons, state whether this function is even, odd or neither. (b) With reference to all relevant...

Let me preface this by saying this is not a homework problem or anything, although it may look like it to some. Also, I don't have much of a math background (Calc I & II, Linear Algebra), but I don't think this problem requires much knowledge of "higher," math; just some good problem solving...

Given: x(t) = cos(2*pi*f1*t) 0 <= t < 4 cos(2*pi*f2*t) 4 <= t < 8 cos(2*pi*f3*t) 8 <= t < 12 f1, f2, and f3 are given as well Would it be possible to combine all three of these conditions into one convenient equation or am I just dreaming? I tried using Matlab to concatenate the three...

The tensile stress in a thick copper bar is 99.5% of its elastic breaking point of 13.0 X 10^10 N/m^2. A 500 Hz sound wave is transmitted through the material. (a) What displacement amplitude will cause the bar to break? (b) What is the maximum speed of the particle at this moment? Comments...

Analysis of the periodic sound wave produced by a violin's G string includes three frequencies: 392, 588, and 980 Hz. What is the fundamental frequency? [Hint: The wave on the string is the superposition of several different standing wave patterns.] The fundamental frequency is the lowest...

Out of KF, NaF, and RbCl, does NaF have the shortest ionic bonds as well as highest lattice energy, and RbCl have the lowest melting point? Thanks

I understand what the Fourier Theorem means, as well as how it behaves, I just don't understand how the math actually pans out or in what order to do what. I'm going to start off with what I know. f(x) = \frac{a_0}{2} \sum_{n=1}^{\infty}(a_n}\cos{nx} + b_{n}\sin{nx}) while, a_{0} =...

Let's consider the motion of a test particle in a central field. Is the Coulomb potential, 1/r, the only one that produces a periodic motion? If no, is there a condition for periodicity to occur? Thanks, Michel

how many elements are there in group 18?

The problem is this: A firework charge is detonated many meters above the ground. At a distance of 400m from the explosion, the acoustic pressure reaches a maximum of 10.0 N/m2. Assume that the speed of sound is constant at 343 m/s throughout the atmosphere over the region considered, that...

Are there any programs available for download that are the periodic table? I am looking for something I can keep on my laptop. Also, can any of you recommend periodic table posters (I am looking for comprehensiveness)?

I am trying to prove that if f(x) and g(x) both have period P, then f(x)*g(x) also has period P. What I tried to do was let f(x) and g(x) be represented as Fourier series f(x)=a_{0,1}+\sum_{n=1}^{\infty}\left[a_{n,1}cos(\frac{2{\pi}n}{P}x)+b_{n,1}sin(\frac{2{\pi}n}{P}x)\right]...

I'm designing an online periodic table of the elements and I have a question about the lanthanide and actinide families. I notice that all periodic tables put them below the main table, aligned with groups 4-18. Does this mean that they fit into those groups? Or is it just placed like that to...

My teacher gave us as excercices this: I'm pretty certain you have to prove it by contradiction, but I don't get how to represent to periodic decimal expension in a proof? Any hint is welcome, thanks in advance.

hey guys - just a question regarding a systems and signals course: if I've got two disctrete signals: x1[n] and x2[n] if i know both signals are periodic (individually) how do i prove the sum of these signals is periodic? requirement for periodicty (one signal): x[n+N] = x[n] where n...

I have yet another problem. Rodolfo paez plans to retire in 20 years he will make 120 equal contributions towards his retirement plan. 10 years after his last contribution he will be making 120 periodical withdrawals of 3500 a month until it reaches 0.the interest in the account is of...

The Janet Periodic Table of Elements (1929) seems more "consistent" than the modern form. The location of any element (row, column) is directly related to the quantum numbers of the most significant electron of the element. Please see; http://ca.geocities.com/chemguy777/index.htm

I can someone pleas help me with this problem? Thanks. A periodic function f has a period of 12. If f(7)=-2 and f(11)=9, determine the value of f (43) how do you do this?

Im working on a periodic table in vb.net and I want to start adding in the information for the density, melting point and boiling point for the elements. The problem that I am having is I need to find a source that I know has only entered these values for a specific temp and pressure. I prefer...

Why are there two rows separate from the general table at the bottom of the diagram? We just started chemistry this week and I'm interested in it, I might try to get it into an online course next year if at all possible, so I just felt like asking a question.

One question posed in a general chem book I have were the trends of a couple of reaction types. They don't answer the question of why, though. Maybe you can help... Identify periodic trends of these rxns: Set 1: H2 + X2 --> 2HX (X are halogens) Ex: H2(g) + Cl2(g) --> 2HCL (g)...

I need to find the best oxidizing and reducing agent in the periodic table and say why i chose what i chose. I think the best oxidizing agent is Fluorine and the best reducing agent is Lithium I am not sure if my predictions are correct and if they are I don't know how to explain why I...

Light glows for every 13 seconds. How many times did it glow between 1:57:58 and 3:20:47am

I'm taking solid state, and again and again we use the periodic boundary conditions, that the wavefunction should be unchanged by displacements of the length of the sample, L (assume 1D for simplicity). The argument was that the surface is so far away that it shouldn't have an effect on the...

I have formula for 1D wave equation: (*) u(x, t) = 1/2 [ f(x + ct) + f(x - ct) ] + 1 / (2c) Integral( g(s), wrt s, from x-ct to x+ct ) I am trying to find u(1/2, 3/2) when L = 1, c = 1, f(x) = 0, g(x) = x(1 - x). However, for (*) to work, the initial position f(x) and initial velocity...

Hi guys. I have to do a little written report about Periodic table and I have to write either about Groups, Periods or Transition elements. I have decided to write about Periods. First I wrote what a periodic table is and how it is formed (just a little histry) then I explained the order...

I am working on a problem that has a few angles of approach. I am hoping to get at least that right before I waste too much more time. The problem is a slender, uniform, rigid rod is placed to pivot on its center, so that the rotation is taking place at the ends of the rod. then a spring...

I don't know how to use the extra condition given in the this problem: f^{\prime\prime}+\lambda f = 0, f=f\left(r\right) f\left(r\right) = f\left(r+\pi\right) For \lambda = 0, the solution is some constant. For other \lambda, I put \lambda=k^2, and get f^{\prime\prime}+k^2 f =...

Hi. I am currently working on a problem involving a ball being dropped from a hieght of 4m making a perfectly elastic collision with the ground. Assuming no mechanical energy is lost due to air resistance, I must find the period of the motion. I used the equation V(final) = V(initial) - gt...

Is there a continuous periodic function which is not trigonometric. if yes, what?

I need to plot several cycles of the output response. The waveform is sawtooth, starting at 0 and taking 1 second to peak at 10, returning to 0 in 1 second. The transfer function is S/S+1 So far I've got 10/1-e^-2s ((1/s^2) - ( e^-s/s^2) - (e^-2s/s^2) as the Laplace Transform of the...

Every "spacially periodic" function [i.e. s.t there exist P s.t. f(x+P,t) = f(x,t)] of the form f(x,t) = X(x)cos(wt) is a solution of the wave equation.

Here is my problem: A hard-boiled egg of mass 45.0 g moves on the end of a spring with force constant k = 24.7 N/m. Its initial displacement is 0.290 m. A damping force F = - bv acts on the egg, and the amplitude of the motion decreases to 0.120 m in a time of 5.10 s. I need to find the...

Which elements have electron configurations different from what the periodic table predicts? I have the d-block, but i don't know how/where to get the rest. Suppose in another universe, everything about atomic structure is the same as in our universe BUT there are 3 possible spin states...

What are the periodic trends? I need help with them.. Regarding atomic mass, (first) ionization energy, electronegativity and anything else I am missing. Specially atomic mass, well as you go down a group and atomic number increases, atomic radius increases, ok this makes sense.. number of...

Hi we're beggining to label the orbitals with s p d structures...grade 11 chemistry The question is "Explain why the 2+ ion is the one that tends typically to form" Ive answered the question above this one which says "Ca element 20 forms a 2+ ion. Write the electron configuration of neutral...

Hello all Is there any good way to memorize the charges of elements in the periodic table? Thanks?

The only thing we know is conscious - ourselves - is a lifeform based on carbon, which is in group 4 of the Periodic Table.Silicon is too.Since silicon is found in computers this raises an intriguing possibility that computers could experience emotions and colours and sounds and so on.Silicon...

Project Help I have a Science project due. I am a little gridlocked... I would like to incorporate a mystery type game to this. What I have is the board and rules, but I need questions. 4 sets. Story (For those who have completed GTA: San Andreas, you may recognize some of the scenarios)...

Periodic Table Game Project HELP! I have a Science project due. I am a little gridlocked... I would like to incorporate a mystery type game to this. What I have is the board and rules, but I need questions. 4 sets. Story (For those who have completed GTA: San Andreas, you may recognize some...

I've got one of those "research in other resources" questions in my chemistry homework. (meaning the info isn't in the lecture or the text, I guess ). It goes like this: Consider Group 1A and Group 1B of the periodic table. The text states that although A groups have very regular patterns...

I've heard that there's a periodic tables of particles, I've searched the net but have yielded little results. Is it still in the works? or is it out yet?

Does anyone have any interesting or easy ways to memorize the first, oh, 10 to 40 or so elements (only including the names and the abbv.)? thanks

How would you go about finding the limits of the general laplace transform function for periodic functions?

If you have a molecule with several elements, how do you figure out how many atoms of each element are in it?

Tools of construction of system of elements. Tools of construction of system of elements. www.genevo.org/B.htm[/URL] An old model of atom does not answer many questions about properties. And... I decided to offer you a new one. It is called "ball-bearing model of atom". It is very flexible...