What is Source: Definition and 1000 Discussions

Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. It most commonly refers to the open-source model, in which open-source software or other products are released under an open-source license as part of the open-source-software movement. Use of the term originated with software, but has expanded beyond the software sector to cover other open content and forms of open collaboration.

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  1. A. Neumaier

    I Particles from a thermal source

    In the following, I want to consider both photons in a sharply focussed, monochromatic beam of light (''type P'') and electrons in an electron beam (''type E'') on the same footing. In the following, X is either P or E. If we only concentrate on the internal degrees of freedom, both kinds of...
  2. M

    Power Source, Current Source and Resistor in parallel

    Homework Statement Consider the circuit shown in Figure P1.68. Find the current i_R flowing through the resistor. Find the power for each element in the circuit. Which elements are absorbing energy? V_source=12 V I_source=4A R=8 ohms Here is a picture of 1.68 Homework Equations P=IV...
  3. wolram

    Is this the source of our galaxy's proper motion

    http://www.sciencedaily.com/releases/2016/02/160209132047.htm Scientists have discovered galaxies through the Milky way haze and posit that these galaxies are the great attractor do you think they are?
  4. DaTario

    Presumed mass content of photon as gravitational source

    Hello, I have read some of the posts which discuss the meaning and mistakes involving the equation: ## m_0 = \frac{h f }{c^2}.## My question has to do with gravitation. I would like to know if it is correct to associate to a photon with frequency f, crossing a region near a mass M, a...
  5. sciencejournalist00

    Can calcium ions be used as a source of entangled photons

    By heating calcium in a tantalum oven and subjecting the calcium vapor stream to blue laser, calcium atoms absorb the blue photons and emit two photons of lower energy as they decay twice. Once they decay from the highest excited state to an intermediate excited state, and then from the...
  6. J

    Revolving light source and creation of angular momentum

    Let's say a train powered by electric third rail drives around without friction on a circular track, and light is shining out of the train windows, said light carries angular momentum, like light emitted from rotating or revolving things tend to do. Where does that angular momentum come from...
  7. T

    Distance from source to observe Doppler effect?

    I was just looking at a few animations and something that could be just visualized incorrectly or I may have interpreted correctly is that the wavelengths coming from the sources are initially smaller close to the source, but become larger as you get far away from the source. Is there any...
  8. Marcin H

    Voltage vs. Current Sources: Understanding the Differences

    Homework Statement Check picture Homework Equations V=IR The Attempt at a Solution I thought I had this right, but then I started thinking about it and I'm not sure anymore. My thought was since the voltage was changing and the current was constant, that the source was a voltage source. I...
  9. U

    Plotting Bode of Resistor w/ DC Source: 20*log(0)

    I am ploting bode of resistor connected with DC source.So no freqvancy at all! The bode magnitude plot should be(or it should start from) 20*log(jw)=20*log(0) (jw=0 because we have dc source) what should be the value??for step of 5v... what should bode look like??
  10. C

    Looking for a source for equation for power

    I'm trying to reference a source for the equation P=(MxAxS)/T. power=(mass x acceleration/gravity x displacement) / time. I can't find a source, any help would be great. Thanks
  11. S

    Astronomical source extraction in non uniform background

    I have been working with some Herschel images and I am finding it difficult to extract the astronomical sources from the image. The image background is extremely non uniform so i am not able to differentiate between the background and the source. I used some tasks in HIPE like source extractor...
  12. sciencejournalist00

    Are probability coefficients source for semitransparence

    If I have a 60-40 beam splitter, I have a semitransparent plate that will classicaly reflect 60% of the light and transmit 40%. On quantum level, photons take both trajectories at the same time, but with different probability coefficients. So is quantum superposition of trajectories for...
  13. W

    Series voltage source vs parallel voltage source

    Power systems isn't my area of specialty and I've been doing some reading where it was stated that series voltage connections are safer than parallel connection. I don't fully understand why though. website address...
  14. CharlesJQuarra

    Einstein tensor of a gravitational source

    In section 4.4 of gravitational radiation chapter in Wald's general relativity, eq.4.4.49 shows the far-field generated by a variable mass quadrupole: \gamma_{\mu \nu}(t,r)=\frac{2}{3R} \frac{d^2 q_{\mu \nu}}{dt^2} \bigg|_{t'=t-R/c} I have the following field from a rotating binary...
  15. kostoglotov

    Why isn't this largest voltage source given as negative?

    This isn't actually a homework problem, but it is an example in a my textbook that I have a question about... imgur link: http://i.imgur.com/2OglMH4.png Ok, I wanted to clarify some things. I understand that current flowing from a positive terminal to a negative terminal represents a...
  16. JordanHood

    Maximum power from a battery with source resistance

    Homework Statement A 5V battery rated at 1800mAh has a soucre resistance of 10 Ohms. What is the maximum power that can be extracted from the battery? Homework EquationsThe Attempt at a Solution I understand that had the battery not had any source resistance then the power out would have been...
  17. F

    Gravitational Lensing Effect: Frequency & Wavelength Change?

    Hello, This is my first post and I have one question. My major is not physics. For now, I am struggling to understand general relativity for own reason because the math involved is troublesome to me but facing one question I need to figure out. It is related with the gravitational lensing...
  18. P

    Find the source of quote in Wikipedia that is not attributed?

    How do I find the primary source of some quote in Wikipedia that is not attributed? I mean how am i supposed to attribute something like that in a paper? paper due basically yesterday, that's why i need help quick.thanks for any help
  19. P

    Doppler effect for accelerated source

    Homework Statement At the initial moment source and detector are located in same point and are both in rest. Source is released into free fall and detector remains in rest. Source has frequency fs=512 Hz and speed of sound is v=340 m/s . When detector detects frquency f =485 Hz , what...
  20. T S Bailey

    Gravitational Stress: Source of Energy for Orbiting Bodies

    Orbiting bodies are often stressed and twisted by the tidal forces of the larger body. My question is, if these stresses cause the planet to heat up then what system provides the energy to do this? Does the larger body lose energy? Can the gravitational field act as a medium for energy exchange?
  21. U

    Good source homework problems for beam spring structures?

    Hello there, In this semester I'm studying the vibrations course. In this course we get questions like calculating the total stiffness, set up differential equations and so on. The book that we use (Theory of Vibrations) has not been very useful, our exams give beam spring structures related...
  22. T

    Java What are some open source projects for gaining experience with Java?

    Hello everyone. I am a computer science and applied math double major. I want to get involved in an open source project so I can gain experience and so I have something to show potential employers that I worked on. I just created a GITHUB account and I am not an expert at using it, nor have I...
  23. T

    Looking for a good source for problem sets

    Homework Statement i'm feeling that i didn't quite catch the whole concept of inertial forces very well , and I'm looking for an additional source for mechanics problems . so far i have been learning and solving problems for "an introduction to mechanics" by danniel kleppner , which is btw is...
  24. Jonathan Scott

    Gravitomagnetic Effect of Moving Source on Test Object

    Consider a gravitational field caused by a central source object and a gyroscope in orbit around that source. It is well-known that the gyroscope experiences rotational frame-dragging at a rate 3/2 times the cross product of the velocity and the field, which is known as the de Sitter precession...
  25. W

    Open source for FE / Fluid Analysis?

    Hi! I'm would like to ask if there's any open source available for FE/Fluid analysis? I'm planning to use it to simulate icing and melting process in a ice storage based on different geometry.Its something like a fridge with coolant ect. I would like to simulate the icing and melting process...
  26. T

    Nodal analysis with dependent voltage source

    Homework Statement In attached image. Just curious as to how their nodal analysis is correct. Homework Equations [/B] ##I_{in} = I_{out}## The Attempt at a Solution Solution in image. I am just not sure how they applied nodal analysis here to find that ##I_s = \frac{12}{12} +...
  27. T

    Finding a current in a circuit with a dependent source

    Homework Statement My problem is in the images attached. Essentially, I just want to find ## I_s ##. Homework Equations ## V = IR ##[/B]The Attempt at a Solution I already have the original solution using KCL, which tells me that ## I_s = 4 A## and that ## I = 1 A##, but I was trying to do...
  28. Raptor112

    Force on a plate from a fluid line source

    Homework Statement A line source of strength 2##\pi##m is located ##a## distance a above a horizontal plate. Find the force per unit width on the plate, ignoring gravity and taking the pressure below the plate to be uniform and equal to the stagnation pressure of the fluid. (You may nd the...
  29. Y

    Why use arbitrary voltage source in Dependent Thevenin's

    Normally, I would just assume that for a circuit with just a dependent source, I can treat it the same as as one with an independent source. Using Picture 1 Assume that I want to find the Thevenin wrt nodes A and B. I want to find Rth, so I zero out all sources, which makes I = 0A. The only...
  30. B

    Can electron be considered a Source of gravitational field?

    Hello PF members, Source of the gravitational field in the Einstein field equations is energy–momentum tensor and the curvature of space-time is directly related to the energy and momentum of whatever matter and radiation are present. Suppose a electron at rest . 1- Can this electron be...
  31. R

    Solving MOSFET Issues | 180 Ohm Resistor

    I am new to using MOSFET transistors as load switches. Here, I am trying to trigger the P-channel MOSFET to run a current through the 180 ohm resistor. I can not figure out what I am doing wrong. It is supposed to turn on for a small moment (at the zero-crossing moment of the AC phase), then...
  32. S

    Nodal analysis with voltage source

    Homework Statement Use nodal analysis to calculate Va, Vb, and the currents IE1 and IE2 without using source conversions I have tried this many, many times, and I must be missing somethingHomework Equations [/B] The equations I came up with: VA-10/ 1.1 + VA/1.2 +VA-VB/1.4 = 0 VB+2/1.5 +...
  33. J

    Circuit analysis current source problem

    Homework Statement given the circuit shown, find V1. Homework EquationsThe Attempt at a Solution see image: am i right? Video says otherwise... I chose to use the superposition theorem here. help appreciated, regards, james.
  34. D

    Young's Interference experiment

    I am not sure if this is the correct place to put this question, as it is rather straight forward. But anyway, does anyone know if/where I could find a scanned (or otherwise copied) copy of Young's original experiment (or his paper(s) on it)? I am doing a project, that amounts to some...
  35. jdawg

    Source Transformations: Find Vth & Rth

    Homework Statement Find the thevenin equivalent circuit by performing source transformations only. Homework EquationsThe Attempt at a Solution Answers: Vth=60v and Rth=30. I managed to get Rth correct, but I'm not sure if everything I did was "legal". I can't seem to find Vth.
  36. J

    Steady State Heat Equation with Source

    I am trying to solve the steady state heat equation with a heat source. I am starting out in 1 dimension (my book gives the solution in 2, but I'm just trying to get a feel right now) and I have a heat source Q, located at 0. It radiates heat through an infinite medium. So what would the steady...
  37. A

    System of lenses with a light source at first focal point

    Homework Statement So I have this system of lenses with this problem: First lens: focal length ##f_1=50 mm## Second lens : focal length ##f_2=400 mm## Distance between them ##d=600mm## A small light source is placed at the focal point for the first lens. At the focal point for the second...
  38. A

    Tracing back an electromagnetic wave to its source

    Suppose you have a solution to the Maxwell's equations in vacuum, and now you want to find what kind of charge/current system create the wave in the first place, can this be done?
  39. madhusoodan

    Van der Pauw measurment- source unit

    I wanted to study electrical behavior of thin films. Can anybody suggest me suitable source measure unit please? (also of low budget) Power supply: Voltage (few volts) measurement: current (micro- milliamps)
  40. A

    What happens to projected light after the source stops

    Let's say a flashlight or a laser is turned on and there's light coming out of it. Once you turn the flashlight or laser off what exactly happens to the projected light? Obviously it won't be visible anymore, but where does it go?
  41. D

    Calculating Power at source from Intensity at distance R

    Homework Statement An enclosed chamber with sound absorbing walls has a 2.0 m × 1.0 m opening for an outside window. A loudspeaker is located outdoors, 46 m away and facing the window. The intensity level of the sound entering the window space from the loudspeaker is 42 dB. Assume the acoustic...
  42. TheMathNoob

    What's the source of power of wizard in the Potter universe?

    For example in DBZ, the level of power is determined by the ki, so what about the potter universe?
  43. S

    Poisson equation in R with a source at the origin

    Homework Statement Solve the poisson eq. on R with a source in x=0. The Attempt at a Solution I haven't done this kind of thing in years, so I'm a bit rusty, but I think that this is requested: \Delta \phi = - \rho \delta(x) (Edit: no wait, I need an integral here). It doesn't seem to be...
  44. J

    Minimum output e.m.f. of the power source

    Homework Statement Homework Equations V=IR For resistors connected in parallel, 1/R =1/R1 + 1/R2 +... The Attempt at a Solution I first calculated the resistance of the the cable which consists of two wires, 1/R= 1/0.0050 + 1/0.0050 R = 2.5x10^-3 x 800 = 2 Ω Then I calculate the voltage...
  45. Spinnor

    Researchers Release First Draft Of Open Source 'Tree Of Life

    From, http://www.ibtimes.com/researchers-release-first-draft-open-source-tree-life-23-million-species-organisms-2105757 In a project funded by the University of Michigan and the U.S. National Science Foundation, researchers from 11 different institutions have finished creating the first draft...
  46. terryds

    Circuit problem -- Voltage source and 5 resistors....

    Homework Statement http://www.sumopaint.com/images/temp/xzkaelnnkibopbdq.png The electric current that goes through the 5 ohm resistor is A. 0 A B. 0,3 A C. 0,6 A D. 0,9 A E. 1,2 A Homework Equations 1/Rparallel = 1/R1+1/R2+... Rseries = R1+R2+... The Attempt at a Solution I take the 6...
  47. S

    Distribution of protons in momentum space in an ion source?

    How are protons in an ion source distributed in momentum space? Consider an ion source fed with H2 at low pressure. As soon as the protons are free protons they are accelerated by the extraction voltage of perhaps 10 kV. In momentum space the protons are initially a "shell" with a certain...
  48. N

    Source of potential energy of body made in space falling

    Hey all, question about gravitational potential energy. If an object begins on ground then gains height when it falls then energy it consumes to fall down was the potential created by moving upwards, if an object was created in space, then moves gravitationally towards a celestial body where...
  49. M

    Find the speed of the source (Doppler Effect)

    A kid is riding a bike and is ringing bell of 3000 Hz. You are standing still on the sidewalk.When the bicycle moves toward you, you hear a shift in the frequency of the bell. In addition, when the bicycle moves away from you, you hear a different shift in the frequency of the bell. If there is...
  50. gracy

    Electric field lines of positive source charge end on ....?

    I have read that electric field lines of positive source charge end on negative charge and Today I came to know that electric field lines of positive source charge end on infinity,which one is correct?I think electric field lines of positive source charge end on infinity if the positive source...
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