Source Definition and 1000 Threads

I have two questions on this topic: 1- What is the difference between free and open source software? Do both mean the same thing? 2- Some free (open source?) software is used by companies to make big money. Aren't these conflicting things?

Homework Statement http://www.chegg.com/homework-help/questions-and-answers/problem-2-variableh-resistor-r-circuit-fig-p224-adjusted-va-equals-60-v-find-value-r-q8083343 Homework EquationsThe Attempt at a Solution Hi, I attached a pdf file with the problem. My question is, for the lower right...

I have two measurement cases in my setup. An divergating laser beam (not an gaussian) is measured at two locations from lens , at nearby i.e. 400 mm, and far away, > 2000 mm away. My lens is an plano-convex lens. Which side should face the laser in these two cases? I know that the...

Homework Statement Maximum power is transferred to variable load when: 1) RL = Rs 2) RL not equal to 0. and Rs = 0 3) RL = 0 and Rs not equal to 0 4) RL = Rs/2 Homework Equations Maximum power theorem RL = Rs The Attempt at a Solution But if Rs = 0, then current is maximum, so load get...

Homework Statement This is related to Astronomy & python . I am trying free-up sources on TS map on a galactic source with python script. But when I run the script, at the end of the process, I get the following run time error. Traceback (most recent call last): File "find_new_sources.py"...

Could we hypothetically use it to create a region of space with the magnitude of the stress component of stress energy tensor greater than magnitude of mass denisty component?

Hello, Analogous to mass of fundamental (not composite) particles coming from interaction of those particles with the Higg's Field, does charge of fundamental particles come from interaction of those particles with some known/hypothesized fundamental field? Thank you!

I have in the back of my head the statement that for every finite sequence of positive integers there exists a pattern (i.e., a generating formula). While this sounds reasonable, I am not sure whether it is true, and if it is true, what the source for this statement is, and how the correct...

If a micro-particle tunnel through a barrier which has higher potential energy than the energy of the particle, then from where does the particle get the energy to cross that barrier?

Greetings! I did the famous "Mass Lifter Heat Engine" experiment in which a mass is put at the top of a piston enclosed within a cylinder. The cylinder is connected to an aluminium canister of air and the air inside this canister expands and contracts the piston with thermal contact. We had 2...

Hi! We will make a lab analogous to the stern gerlach experiments but with polarized light. How can we get only one single photon in experiment with a coherent light source? I'm going to make a lab where we need to get in only one single photo at a time. I have read that you can use some...

Homework Statement Organ pipe sound is driven by a compressed air jet flicking alternately in and out of the pipe in step with the fundamental frequency. My question is whether sound waves of the higher frequency harmonic series are emitted during the intervals when the jet is outside of the...

Hi, I'm struggling with source-free RL Circuit derivation. In the books in the right side diagram they've reversed polarity of inductor to get equation: V(r) = - V(L) But why? I checked google and everywhere they had put inductor with positive sign upwards. Here is what I think-- In left...

Homework Statement Homework EquationsThe Attempt at a Solution I have attempted and completed all questions. However, I am now trying part (b) with transforming the voltage source into a current source. I am unable to work out the current and I am unsure what to do next. I have included my...

TL;DR Why does the Einstein equivalence principle imply that all forms of (non-gravitational) energy source curvature? Now, as understand it, the Einstein equivalence principle (EEP) implies (or at least suggests) that gravity is the manifestation of spacetime curvature, the reason being that...

Homework Statement Select the correct expression for ##i_o(t)## for ##t≥0^+##. Homework Equations ##V(t) = V(∞)+[v(0)-v(∞)]e^{\frac{-(t-t_0}{\tau}}## ##i(t) = C\frac{dV(t)}{dt}## ##\tau = RC## The Attempt at a Solution I'm a bit stuck on this problem. Specifically, I'm not sure how to deal...

I'm looking for a source of harder mechanics problems, preferably with solutions. I'm supposed to use the Young and Freedman book, but I find it rather teadious and superficial; most problems don't match the difficulty and depth of the ones on the exam. I had my mid-term tests recently, and got...

About 10 days ago, I read this in the Nature journal: http://www.nature.com/news/colliding-stars-spark-rush-to-solve-cosmic-mysteries-1.22829?WT.ec_id=NEWSDAILY-20171016 I quote: "Over the past decade or so, astrophysicists had come to believe that this was the most plausible mechanism to...

Homework Statement The current source and voltage source in the circuit shown in the Figure below are connected in parallel so that they both have the same voltage, vs. The current source and voltage source are also connected in series so that they both have the same current, is. Suppose that...

Homework Statement Solve ##\Delta\phi = -q\delta(x)## on ##\mathbb{R}##. Correct answer: ##\phi = -\frac{q}{2}|x| + Ax + B## Homework EquationsThe Attempt at a Solution In one dimension the equation becomes ##\frac{d^2 \phi}{d x^2} = -q\delta(x)##. We integrate from ##-\infty## to ##x## to...

I have one circuit and another with a source transformation figure a and b respectively. My question after transforming the 30 mA source shouldn't the current going into node 5 equal the current going into node 4? Figura a. Before the transformation of the source Figure b. After the...

If I have a resistor and a voltage source in series but then I apply a short circuit in parallel to both of them would the voltage source and resistor not receive 0 V? Thus having 0 current. What would change in the circuit?

Homework Statement You are placed in a 2-dimensional labyrinth at a starting location ##s## and must travel to n goal locations ##g_1, g_2, ..., g_n##. Determine the optimal path using the A* algorithm. g = goal cell, s = start cell example input: 3 11 //row length, column length # # # # # # #...

Lets say I have an LED that is being pulsed once every two seconds. The LED uses 5 mA of current each time its fired and the pulse lasts for 40mS. I know the current into the LED because I measured the voltage drop across the dropping resistor of 420 ohms with a good O-Scope. So I know all...

Hi. I would like a source code to integrate the ikonal equation. I would like to compute the ray path. Of course I am able to compute the phase refractive index n(x,y). Cartesian system is preferred. Can anybody give me a suggestion? Bye, Carlos

Homework Statement Here is a diagram of the circuit and my redrawing with currents drawn: We are to find the power delivered by the dependent voltage source. I found a solution online, but I am not sure why they had the KCL line as: $$ \frac{v_1 - 160} {10} + \frac{v_1} {100} + \frac{v_1...

i was reading about CSI and the first paragaph said "A constant current source is assumed here, which may be realized by using an inductance of suitable value, which must be high, in series with the current limited dc voltage source. " and it says nothing else about it , so clearly it's a basic...

Hi guys, is the current flow in this picture correct? I'm trying to understand current flow in a two source circuit.

Can anyone give me a source for these resistors please?

Say I have a constant source of 1 volt that will not diminish in volts during use and would like to collect that energy how would I do it. I have been trying To figure this out for the past month and source really appreciate some help. Thanks

Hello everybody I got really confused. I want to calculate the Electric-Field of an alternating current source( Sine(wt)). I do not know what is its equation. I need to run it in Matlab to get a result. Can you please give me some hints? I need to write the equation to calculate the E-field in...

I read that spallation is the process where you have a high energy proton source (a linac or other particle accelerators for example) and you direct those protons into a metal target which is of specific alloy or whatnot and you get that the protons impacting the material release secondary...

Hello, can you help me? In my model, I have to simulate source distribution in two volumetric cells (30 and 31). For example, with a photon source of 356 keV, I have to simulate the distribution according 0.2 (20% in source 30: thyroid without nodule) and 0.8 (80% in source 31: nodule). I use...

Homework Statement here is my problem : Homework Equations like usual, the problem is related with RLC circuits and transients The Attempt at a Solution [/B] from here, the solution is obviously wrong because from the solution, its alpha should be -300 and not -0.4...and from the...

Lately, I've wanted to build a compact source of synchrotron radiation that is accessible to researchers with size and budget constraints. So far, I've managed to outline designs of the superconducting dipole magnets that will be used to keep electrons moving in a ring path within the booster...

Hi, I've looked through some of the replies regarding this topic on this forum, but I'm still a bit hazy on the topic. So this is my problem, why do current try to return to its source? I'm trying to understand this problem with the premise that as long as there is a potential difference...

Hi, I know that if you put a dipole and a neutral molecule at a certain distance, there is the Debye's force that attract them. If you put the same molecules in the first position, they will attract another time. I know this can be a stupid answers, but what's the font of that energy? The...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] Hi, I was working on a the source transformation and i got to the part where there are two current sources in the circuit. The current sources were added together (giving they were going...

Homework Statement In the circuit below, the RMS of the AC source is 100V, the inductive reactance is 50 ohm, the capacitive reactance is 200 ohm, the resistance is 40 ohm and the current flows in the circuit is 0.644 A. Determine the reading of the voltmeter. Homework EquationsThe Attempt...

Homework Statement Homework Equations Impedances: Inductor = jωL; Capacitor = 1/jωC The Attempt at a Solution I attempted to excite the circuit with an Io = 1A source, and then from Zc = 1/jX2 justify Vx = (1)(Zc) Thus, substituting our found Vx and then doing a source transformation, we...

Homework Statement below is my question : Homework Equations all of the equatios used to solve this problems are equations for free source RLC circuit. The Attempt at a Solution so far i have solved problem (a), whose answer is -1400V/s, the problem is when i want to solve (b) and (c) do...

Is the work done by a constant voltage source positive or negative when current is opposite to emf?

Hi friends in my class we had to study some topics out of our interest .. i tried for along time to understand them but the teacher's slides is not enough for understanding so i ask if anyone can give me sources to study the topics (the same way ) which attached as a photo note : i studied...

Homework Statement An ac series circuit consists of a voltage source of frequency f = 60 Hz and voltage amplitude V, a resistor of resistance R = 163 ohms and a capacitor of capacitance C = 6.2x10^-6 F. What must the source voltage amplitude V be for the average electrical power consumed in...

Hi. I'm trying to create a power generating technology for a sci-fi story that is ubiquitous in everyday life (e.g., flying cars, starfighters, elevators, homes, etc.). One element I need is for the power core to be able to overheat and kill a human in a starfighter. Is there an existing or...

how does the doppler effect work when the observer and source are not moving in a straight line, what do we take in as the velocity of the observer and the source in the doppler effect equation?

Homework Statement A stationary police car emits a sound of frequency 1200 Hz that bounces off a car on the highway and returns with a frequency of 1250 Hz. The police car is right next to the highway, so the moving car is traveling directly toward or away from it. (a) How fast was the moving...

Homework Statement Why does a source moving perpendicular to the line between it and the observer produce no doppler effect?Homework Equations The Attempt at a Solution I have heard the the radial velocity of the source relative to the observer must be zero but i don't understand why, if the...

In 3rd edition of Goldstein's "Classical Mechanics" book, page 335, section 8.1, it is mentioned that : In Hamiltonian formulation, there can be no constraint equations among the co-ordinates. Why is this necessary ? Any simple example which will elaborate this fact ? But in Lagrangian...

I'm new to this so please correct me if I'm doing this wrong. I'm curious to know about what practical uses are there for nuclear fusion other than a green power source.? I've already seen a few readings and a video from a Michel fellow about how it works, and it's fascinating stuff I'm not much...