Short Definition and 523 Threads

  1. E

    Short Beam Stress Concentration

    Hi there Are anyone familiar with tables of stress concentration factors, or the like for short beams for different span/depth ratios. My beam is technically not a beam, but I would still like to estimate maximum bending stresses related to normal stresses caused by bending moment (sigma =...
  2. Fredrik

    Short summary of the essentials of set theory

    I've been talking to a guy who doesn't know anything about sets, and I couldn't think of anything good to recommend that he should read. I know that there are lots of good books about set theory, but don't they all cover too many details so that it takes too long to get an overview of the...
  3. P

    Engineering Synchronous Machines - Open Circuit and Short Circuit Tests

    This was a theoretical / rhetorical question posed by the professor during class. He hinted that this will be on the next quiz. I think I know the answer, but can you guys verify it for me? Homework Statement Why do we not perform the Open Circuit Test and Short Circuit Test one after...
  4. D

    Short Lorentz derivation problem …

    I had 1 year ago a little discussion with DaleSpam about the short Lorentz derivation (triangle) if a photon alone can be seen as a light beam. 1) The long Lorentz derivation seems me correct, so no discussion about that 2) For the short Lorentz derivation with the triangle (c.t , v.t and...
  5. B

    Engineering Calculate 3ph short circuit symmetrical fault, per unit method.

    Homework Statement Calculate the three-phase short-circuit fault currents flowing into all five busbars. Homework Equations MVA base = 150MVA All base voltages were set to the local busbar voltages. Formulas I have used can be seen in the attached photos. The Attempt at a...
  6. Q

    Are There Deficiencies in Newton's Laws?

    So I am studying the laws of Newton and I am wondering,are there any deficiencies related to the laws?I mean,somewhere where I can't use them or anything?
  7. M

    Why an electromagnet doesn't makes a short circuit?

    How can you have a simple coil connected to a battery without having a short circuit in it? How do they make electromagnets that don't heat the battery? Thanks :)
  8. F

    Considering a short parabolic impulse as direct current?

    Is it possible to consider a short (20ns) impuls of only one polarity as a short segment of direct current in a simple circuit where the reflections are to be analyzed? If not, how should I treat this kind of voltage waves? The voltage is obviously not constant, but I wonder if it is possible...
  9. A

    Why is voltage 0 in a short circuit?

    We know that U=IR (ohm's law) in a short circuit, R goes to 0, I goes to infinity so the voltage goes to 0*∞ which is undefined! Why voltage is 0?
  10. F

    Doubt about two limits (short)

    Homework Statement Find the limit of ##1): \displaystyle \lim_{n \to +\infty}(\frac{f(a+\frac{1}{n})}{f(a)})^{\frac{1}{n}}## ##2) \displaystyle \lim_{x \to a} (\frac{f(x)}{f(a)})^{\frac{1}{ln(x)-ln(a)}}(=1^{\infty})## I am not quite sure if i can solve it the way I did, it has been to easy...
  11. Spinnor

    Fields of a very short laser pulse, pulse a fraction of wavelength.

    Scientists can produce laser pulses of order one wavelength in "length" see, http://www.bbc.co.uk/news/science-environment-19489384 Do Maxwell's equations admit solutions of such short pulses? Can one approximate such a solution by multiplying a plane electromagnetic wave by the...
  12. J

    The Evolution of Dogs: Domestication in a Short Time Period?

    I understand and completely accept the evidence for the former but i was just reading the greatest show on Earth and richard was saying how our domestic dogs are directly evolved from wolves, not foxes or anything else. If that's the case, wouldn't the lame argument "if we evolved from chimps...
  13. M

    One corner short of a pentagon What does it mean?

    "One corner short of a pentagon"...What does it mean? Ok I read this phrase somewhere and I have no idea what it means. Apparently it's a North American thing and is something related to someone's personality or stuff like that. Can anyone tell me what it is supposed to mean? Thanks
  14. B

    Radiation vector for a short dipole near a perfect magnetic conductor

    Hi there. If I wanted to calculate the radiation vector (in z > 0) produced by a short dipole with uniform current Io (+z direction) on a infinite perfect electric conductor (plane z=0), I'd have to apply the images method. So I'd have to calculate the radiation vector produced by two short...
  15. W

    Allowable load in short compression member

    My apologies, I don't own a scanner or else I would show the 200 variations of formulas I've played around (my work) with all day to get these answers. Question is this; A short compression member is fabricated from 2 steel pipes. the pipe on the top has a cross sectional area of 3.17 in sq...
  16. C

    Short Circuiting an Ideal Capacitor

    Hi all, My question is what happens if I short circuit a capacitor with fully ideal wires. It is obvious that it will become chargeless but where does its energy be used? Is it possible to explain this system theoretically or we must always consider a parasitic resistor in these kind of...
  17. A

    Why is this false? - Short Fitch proof using Herbrand logic

    Hello, folks. I'm taking my first formal logic class and some of the things seem contradictory; I know it's because I'm not fully understanding something, but I don't know what I'm not fully understanding—I hope someone can help me. The problem begins: The statement I'm having trouble...
  18. T

    Transformer, flux linkage and emf short question

    http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_s05_qp_4.pdfHomework Statement 6b Homework Equations flux linkage = BA B=F/iL The Attempt at a Solution from my understanding, if B=F/iL , if the current is zero...
  19. qspeechc

    LaTeX Pdf of Not So Short Intro to Latex

    Pdf of "Not So Short Intro to Latex" Hi everyone I'm trying to download "The Not So Short Introduction to LaTeX2e" by Oetiker, but every link I try I get the message "This webpage wants to run the following add-on: 'Zeon Corporation' from 'Zeon Corporation'." Then I am asked if I want to allow...
  20. A

    Very basic, short impulse problem. Just need some explanation.

    Homework Statement If the magnitude of the Earth's momentum is P, what is the magnitude of the impulse that the sun applies to the Earth during six months? Homework Equations The Attempt at a Solution I know the solution is 2P, and I'm pretty sure it's just due to the change in...
  21. I

    Engineering Circuit Analysis of driven RC Circuit with short circuits

    Homework Statement Determine the value of the current labeled i and the voltage labeled v at t=0+, t= 1.5 ms, and t = 3.0 ms. Homework Equations Ohm's law: v = i *r Decay in source free RC Circuit v(t) = v@0 * e^(-t/RC) The Attempt at a Solution i(0-) = 0.1 A. Therefore, v across 200 ohm =...
  22. B

    Resistor and Current Source in Parallel with Short Circuit?

    This circuit is really confusing me. I'm trying to find i using KVL and KCL. What's throwing me off is the short circuit effectively created by the inductor. I know that the whole circuit can't be short circuited because there is a current source that is preventing all of i from going through...
  23. B

    Is the current view of the intergalactic speed limit short sighted?

    Is the current view of the intergalactic "speed limit" short sighted? Just a question that may have some enlightening answers... Einstein says that the interstellar speed limit is the speed of light. What happened to E=MC2? If mass doesn't convert to energy till accelerated to the square of...
  24. Saladsamurai

    Short Beam Bending: Roark's Formulas For Stress and Strain

    Is anyone familiar with the Roark's text that can clarify some terms for me? I am trying to clarify what Roark is referring to in the above mentioned text in the section on short beams (in the 5th edition 7.10 and in the 7th edition 8.10). Throughout the text, he uses the terms "span" and...
  25. K

    Short term atmospheric retention.

    What timefram does short term atmospheric retention mean?
  26. R

    Output short protection circuit

    I am making a totem pole digital output of 1.5-23v. i was searching for a protection circuit for the output short to ground and +24v dc. please help me out by sending a diagram of the circuit if possible.
  27. B

    Engineering How Do Reactors Affect Short Circuit Current in a 3-Phase Power System?

    Homework Statement A 3-phase, 10KV, busbar of a power station is divided into three sections joined by two reactors as shown in Figure 1. Each section contains a synchronous generator and supplies a transmission line through a transformer. The parameters of generators, reactors and...
  28. J

    Long vs Short light wavelength absorption

    Hi all I was reading through an astrophysics book{1} and there I came across this sentence: " A dust cloud can either scatter or absorb light that passes through it. Since shorter wavelengths are affected more significantly than longer ones, a star lying behind the cloud appears reddened...
  29. W

    Is this a short, marvelous proof of Fermat's Last Theorem?

    Given: x, y, z, n are whole natural numbers, including the regular and irregular prime numbers; x and y < z. The, "Trichotomy Law", which states there are three relations possible between (x^2 + y^2 ) and z^2, i.e., < = > . Any square can be subdivided into an infinite number of 'sum of two...
  30. H

    Short dipole radiation resistance - do you have experimental results?

    I have seen two formulas for a short dipole radiation resistance - according to one it is about 200*(l^2/λ^2) Ω, according to the second about 800*(l^2/λ^2) Ω. Which of these is correct, if any? (Let us consider a resonant short dipole, connected to proper inductance). In particular, I would...
  31. O

    [Statistics] Obtaining test statistic in short problem

    Hey everyone! Exam practice, that time of year. In this problem 13 with correct answer C, I'm not sure how they get the test statistic: http://i.imgur.com/doar3.jpgI think they want you to use a F-test, that tests the entire model, which is calculated by: F= ((R^2)/ K)/ ((1 - R^2)/(n-K-1))...
  32. JJBladester

    What happens in a short circuit situation (parallel)?

    Homework Statement What will be the current flowing theoretically through each resistor this short-circuit case? Homework Equations V=IR I=V/R R_{T}=\frac{1}{\frac{1}{R_{1}}+\frac{1}{R_{2}}+...\frac{1}{R_{N}}} For a closed loop, \sum I_{entering}=\sum I_{leaving} The...
  33. G

    Short Circuit Current, EMF, Internal Resistance

    Okay so I have conducted an experiment to find the internal resistance of a battery pack by gradient of a graph of voltage against current. All so far okay. I went on to find the EMF also, again all so far okay. Now I need the short circuit current, and I can't find any information anywhere...
  34. N

    I have few doubts regarding short circuit test of transformers.

    Hi, What does rated output in a transformer signify? Is power same(or almost same) on both sides? In short circuit test, we apply reduced voltage to HV winding so as to circulate rated current in HV. This will cause rated current to flow in LV. But as per definiton of rated current...
  35. S

    Question regarding voltage and current across a short circuit

    When a short circuit occurs, why won't the light bulb light up as well? Since the short circuit and the main branch where the lightbulb is are connected in parallel so won't the two have equal voltages and hence the bulb will light up (P=V^2/R)? Some people told me that its because the...
  36. O

    Conceptual short circuit diode / zero-bias base collector junction BJT question

    Why exactly is there zero current flowing through a diode when it is short circuited, given the presence of the barrier potential? My current understanding is that the drift current precisely balances the diffusion current. But if you take a diode and short it with a wire, wouldn't you then also...
  37. B

    Solenoid design: Can a short solenoid have a long stroke?

    Hey, I'm wondering if a short solenoid (50mm) would be able to pull a 300mm core through it if it was open at both ends? Or would the soleniod stop acting once the core had come to the far side? I've attached a pic of what I'm trying to do (forgive the paint drawring). I'm basically trying...
  38. Femme_physics

    Short question about graphing AC voltage before rectificaiton

    http://img521.imageshack.us/img521/8044/mycircuittt.jpg Considering VP to the ground... I draw only the negative pulse to define it, right?
  39. T

    Faulty lamp because it short circuit

    Homework Statement http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_s06_qp_2.pdf number 7aHomework Equations None reallyThe Attempt at a Solution The answer is that C is the faulty lamp because it short circuit. But how do I know...
  40. srfriggen

    Short Proof regarding elements of a vector space

    Homework Statement Let V be a vector space and v, w two elements of V. If v+w=O, show that w=-v Homework Equations The Attempt at a Solution This is my attempt: 1. v+w=O 2. v+(-v)=O 3. v+w=v+(-v). Subtracting v from both sides yields: 4. w=-v The solution...
  41. M

    How to make the total length of a trail as short as possible?

    I'm just curious. Let's say a trail designer who works for a Boy Scout camp wants to build two trails that connect two campsites to the OA ring. How would he go about doing that? I know that he would not use reflections (he would if he were, say, locating a point across the river such that...
  42. N

    Engineering Calculating line currents if one leg of a star system is short circuited.

    Hey guys, Been struggling with this for ages any help would be awesome. In Electrical engineering; Suppose you have a balanced multiphase star system with a given line voltage. The impedance of each phase is also know. If one of the coils is short circuited, calculate the line...
  43. C

    Medical Short burst of hypersensitivity disorder?

    Hey guys, I am curious about a condition I have had ever since I can remember. It is a short burst in hypersensitivity especially in hearing and touch. It last for up to about 2 minutes and is quite annoying. It makes every movement feel more difficult and exhausting. When I listen to music...
  44. nomadreid

    Short question about probability amplitudes

    When one says the probability amplitude for a quantity when it has probability P, which one does one take, the a+bi or the a-bi?
  45. M

    Voltage and Current Behavior in Parallel Circuits

    Hello Everybody, My question is: Why when a resistor is in parallel with a "short circuit" the voltage across the resistor is zero, & so will the current passing through it? But when instead of a resistor we have a voltage source, this is not the case? "I was informed that the voltage source...
  46. F

    Is the Transformer Short Circuit Calculation Correct?

    Ok I've read a lot of articles and seen a lot of different ways of calculating the short circuit current at the transformer terminals. So I'm going to apply my own intuition and see if I can arrive at the correct value if someone could please confirm my answer. 6.6kV/400V 3 Phase 10MVA...
  47. M

    Torque Calculation. Short- Am I correct?

    Homework Statement What is the torque on the steering wheel? Homework Equations I don't know how to draw on here. Steering wheel is circular. It has a Diameter of 300mm A force of 20N acts downwards toward the 3 oclock position A force of 10N acts Upwards toward the 9 oclock...
  48. V

    Why is is easier to push a heavy load on wheels with a short lever

    Why is it easier to push a load on a wooden crate on wheels when you are nearer the load and the lever is shorter and at a sharp angle compared to pushing a load with the lever lengthened and at a more relaxed angle with your body further away?
  49. A

    Category theory: Prove that two given short Ex. Seq.s are isomorphic.

    I've attached the problem statement and the solution in a pdf file, please check it and see if I've done it correctly. I'm new to abstract reasoning, I've only had a one semester introduction to group-theory and parts of ring theory based on baby Herstein, so I need others to check my proofs to...
  50. S

    Short GRB's: Neutron Star Merger Evidence?

    Is there any actaul observational evidence that short burst GRB's are casued by neutron star mergers?
Back
Top