Difference Definition and 1000 Threads

We have a population of y = 1000 at year 1980 (call it year 0). Every year the population growth rate is 5% per year. y' shows the growth rate of the y (population). Since the population grows by 5% every year, the growth rate is: y' = 0.05y. This is a simple differential equation. When y(0)...

In his book on EM, Griffiths states: Formally, electro/magnetostatics is the régime $$\frac{\partial \rho}{\partial t}=0, \hspace{0.25in} \frac{\partial \vec{\boldsymbol{J}}}{\partial t}=\boldsymbol{0}$$ He explains how in electrostatics charges do not move, or (more specifically), charge...

Hi, given Sql server executes queries order from, where, group by, having, select, order by. Why don't we write queries in same order? Would that improve speed of execution ?

What is the difference between "serious" and "careful"?

As we know, in the case of an atom, 1 mole of C = 6.023 X 10^23 C atoms and in the case of a molecule, 1 mole of C molecule = 6.023 X 10^23 molecules. as we know, atoms are used to make molecules, So can I say 1 mole of C atoms make 1 molecule of C because what we get If we break 1 molecule of C...

Homework Statement Two cells of same emf E and different internal resistance r1 and r2 are connected in series to an external resistance R.The value of R for which the potential difference across the first cell is zero is given by (A) R=r1/r2 (B)R=r1+r2 (C)R=r1-r2 (D)R=r1r2 Homework Equations...

I was wondering what the difference was between the valence band and fermi level? How do we distinguish between the two? Thanks in advance.

What is the difference between 1 kgf and 1 Newton?

So an object unaffected by any gravity free floating in space has zero mass. Now could this object reach light speed. Or am I confused?

Homework Statement Homework Equations ##ΔV=Ed## The Attempt at a Solution ##V_A=E l## ##V_b=0## , because point B is perpendicular to the electric field ##ΔV = V_a + V_b## = El Is my answer correct ?

Homework Statement I'm not understanding the difference between them, this is for Uniform Circular Motion. Homework Equations ar = -ac = -v2/r The Attempt at a Solution So what i know is radial acceleration goes in a direction towards the radius (perpendicular to velocity), and tangential...

I feel like the vector space ##\mathbb{R}^n## differs from other vector spaces, like ##\mathbb{P}##. For example, if we wrote down an element of ##\mathbb{P}##, like ##1+2t^2##, this is an object in its own right, with no reference to any coordinate system or basis. However, when I write down an...

The Lagrangian in classical mechanics is known to be a difference of the kinetic and potential energy. My first question is - why? I.e. are there any reasons (except for "because it works this way") to have it as this difference of energies? The second question is why is it this very value...

Homework Statement Homework Equations V = kq / r The Attempt at a Solution VA = k q / rA VB = k q / rB rB = √((√8 * R)2 + R2) = 3 R VB = k q / 3R ΔV = | VA - VB | = | kq / R - Kq / 3R | = 2 kq / 3 R Can somebody check my answer please ?

Could you please help me to understand what is the difference between notions of «transformation» and «automorphism» (maybe it is more correct to talk about «inner automorphism»), if any? It looks like those two terms are used interchangeably. By «transformation» I mean mapping from some set...

Homework Statement An organ pipe with one end open and the other closed is operating at one of its resonant frequencies. The open and closed ends are respectively: A. pressure node, pressure node B. pressure node, displacement node C. displacement antinode, pressure node D. displacement node...

Homework Statement Homework Equations V=kq/x The Attempt at a Solution I know the correct solution. It's... On my first attempt, rather than use (d+x) in the denominator and integrate from 0 to L, I instead used (x) and integrated from (d) to (L+d). This produces the wrong answer...

Homework Statement Homework EquationsThe Attempt at a Solution If we consider the bigger semicircular arc BD alone then potential difference between B and D will be 4BvR . If we consider smaller semicircular arc AC alone then potential difference between A and C will be 2BvR . If we...

ΣHomework Statement A massless rope is pulled at from both ends. At end A, the force applied is a pull of 10N. On end B, the force applied is a pull of 5N. What is the tension of the rope? Homework Equations a=ΣF/m The Attempt at a Solution I understand that the rope would accelerate...

Homework Statement "Suppose ##f:(a,b) \rightarrow ℝ## is differentiable at ##x\in (a,b)##. Prove that ##lim_{h \rightarrow 0}\frac{f(x+h)-f(x-h)}{2h}## exists and equals ##f'(x)##. Give an example of a function where this limit exists, but the function is not differentiable." Homework...

I am to use this formula: https://d2vlcm61l7u1fs.cloudfront.net/media/fee/fee798ea-5480-47af-9904-35c76ac35e25/phpSzecLa.png I tried using intergral of (E*dr) as in the equation to integrate over the distance of V(2A)-V(0) But when i am to plug in zero into my integrate it would give a math...

Hi PF, initially I would like you to focus on that link https://books.google.com.tr/books?id=Dkp6CwAAQBAJ&pg=PA389&lpg=PA389&dq=runge+kutta+method++is+tvd+proof&source=bl&ots=47ULQDVwcC&sig=e2zjdnXENJ7WxBbrf6hXkSouvLI&hl=tr&sa=X&ved=0ahUKEwjU5Z2XsbXZAhUMCMAKHWpnATQ4ChDoAQhKMAQ#v=onepage&q=runge...

Hello! I found this questions in several places, but no answer made me fully understand it, so I decided to give it one more try here. I am not sure I understand the difference between them in GR. I have a feeling of the proper time as the time measured by the clock of someone moving with a...

1. Homework Statement Two speakers S1 and S2 derived by the same amplifier and placed at y=1 and y = - 1.The speakers vibrate in phase at 600 Hz. A man stands on the x-axis at a very large distance from the origin and starts moving parallel to the Y - axis. The speed of sound in air is 330ms-1...

What is the difference between the gravitational force and gravity? Because I was under the impression that gravity is not a force, but one of the 4 fundamental forces of nature is the gravitational force, so I was wondering what the difference between the two is?

Homework Statement A straight copper wire that carries a sinusoidal current with an alternating frequency of 50 Hz and a maximum amplitude of 0.5 A passes through the centre of a circular ring of a second copper wire, with the two wires orientated perpendicularly to each other. The radius of...

Homework Statement In a TV tube, an electric potential difference accelerates electrons from a rest position towards a screen. Just before striking the screen, the electrons have a wavelength of 10×〖10〗^(-11) m. Find the electric potential difference. Homework Equations ∆E_K=q∆V λ=h/mv The...

Homework Statement Homework Equations C = Q/V The Attempt at a Solution Q1 = Q2 C1*V1 = C2*V2 2*V1 = 5*V2 V2 = 2/5*V1 V1+V2 =100 7/5*V1 = 100 V1 = 71.4 V Can someone verify my working? Thanks!

Homework Statement I found out that Bauxite has 2 formula, which one is 2Al(OH)3, and the other one is Al2Si2O5(OH)4⋅2H2O. What's the difference of these formula? Homework EquationsThe Attempt at a Solution

Homework Statement I'm a bit stuck on how to approach this problem. A miniature spectrometer used for chemical analysis has a diffraction grating with 800 slits/mm set 25.0 mm in front of the detector "screen." The detector can barely distinguish two bright lines that are 30 μm apart in the...

Homework Statement You’ve decided to protect your house by placing a 5.0 m tall iron lightning rod next to the house. The top is sharpened to a point and the bottom is in good contact with the ground. From your research, you’ve learned that lightning bolts can carry up to 50 kA of current and...

Homework Statement I'm kind of confused between DFT and DTFT. Here is my understanding: Okay, so let's say we have time domain, continuous, analogue signal from a sensor - ##x(t) ## 1. We sample this signal, giving us something like the following with an impulse train Now this is a...

Hi. I am working in on a Ring Main Unit of Siemens make. Today, my senior asked me the same question. As per my understanding, a circuit breaker is make or break switch. I mean, when fault occurs the circuit breaker trips, protecting the equipment connected to the line. I have no information...

Homework Statement Homework EquationsThe Attempt at a Solution Apologies for the question image not being very clear . I will refer capacitors by numerical value of their capacitance . The 6 , 4 , 8 capacitors are in parallel . 9 , 9 , 7 are shorted out .So , we can remove them from the...

Mod note: Moved from Precalc section of Homework & Coursework 1. Homework Statement Km = 1024 m km = 1000 m Is this true or not? Because K = 2^10 while k = 10^3? Homework EquationsThe Attempt at a Solution

Homework Statement Determine the Finite Difference Method stencil for approximating a second derivative u''(x) at a discrete set of nodes with maximum accuracy for stencil of sizes (0,4) (off-centered). My questions: I think I am able to answer the question I am just not sure about what is...

In simple words, what is the difference between log and ln?

Homework Statement I am after PC - PA However I must do so without breaking into components. My problem has different values L=3 H=4 SG=1.2 downward a = 1.5g horizontal a = 0.9g and my coordinate is conventional positive y up and positive x to the right cos##\theta## = 3/5 sin##\theta## =...

Today I took two coils and connected one of them (coil A) to an AC power supply. I held the second coil (coil B) close to the first one and then connected them both to a dual trace CRO. As expected, an emf was induced in coil B and the traces on the scope were 90 degrees out of phase. As I...

Can anyone please explain to me in simple terms what the difference is between a trapped surface and an event horizon. I'm not familiar with global general relativity so cannot understand any of the results I've looked up by googling. I think that Tipler has said that when the future C-boundary...

I looked up and read the definitions in several different books, but still don't get it. Is someone willing to explain it to me on a really simple level?

Hi, I'm a high school graduate who's been going through some UNISA (University of South Africa) mathematical modelling material and I've come across the following difference equation - a(n+1) = 1 - a(n). The answer given in the material was that the solution alternates between a(0) for n even...

if a function is one to one, the function maps every element of set A to 1 element of set B. If a function is well defined, if ##(a,b),(a,c) \in f,## then ##b=c## These seem the same to me; do they mean the same thing?

Homework Statement :[/B] This is isn't exactly a problem,but actually something i don't understand in the book i was following, so there this art. about 'Principle of a Generator', whose description is given as, " A generator is an instrument for producing high voltages in the MeV range. Its...

These are the two things that I'm going over in my PreCalculus class- the Difference Quotient and the Average Rate of Change of a Function. I'm confused as to what exactly they are, and how they relate to each other. Average Rate of Change= ##\frac {f \left(b\right) - f\left(a\right)} {b - a...

In scientific experiment, we often have a physical property that can change but have no detectable impact on the measurement. For example, suppose I have a mass of (say) 30 grams attached to a string passing over a pulley. I can add up to another 2 grams and the system doesn't budge. In our...

To my knowledge, CPP means cast-polypropylene, which I've seen used in a coaxial cable. Some cables use CPP as dielectric material. My question is: 1. what is the difference between PP(polypropylene) and CPP? 2. How is CPP made? 3. Is the permittivity and loss tangent of CPP different from that...

Hi everyone Both Draftsman and Designer uses CAD Softwares what i want to know the difference between them according to 1- Educational level 2- Job Roles 3- maximum Promotion can get Thanks

Does potential difference only indicate how much energy each coulomb have, or make current flow, or do both?

Okay...I got a question. Charges move in a wire due to an electric field across its ends. Now, positive test charge in an electric field would have higher electric potential nearer to the positive plate than anywhere else. Now in case of a circuit, like the one I have drawn, the electric...