Multiple Definition and 1000 Threads

A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined together, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train control.
Although multiple units consist of several carriages, single self-propelled carriages - also called railcars, rail motor coaches or railbuses - are in fact multiple-units when two or more of them are working connected through multiple-unit train control (regardless if passengers can walk between the units or not).
The term multiple unit does not denote locomotives using multiple-unit train control.

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  1. B

    Transformer: single primary coil and multiple secondary coils

    If I have a coil with 10 turns and a primary voltage $$V_p$$ and primary current $$I_p$$ and a single secondary coil with 10 turns, I understand the power in the secondary will be $$P=V_pI_P$$ and hence voltage and current in the secondary coil will be the same. If I now bring a 3rd coil with...
  2. G

    System of multiple conductors: image method

    Homework Statement The following figure represent the traversal cut of a system with two cylindrical equal conductors of radius r0 length l at a distance d from one another and at the same distance h of a plane conductor (conductor zero). The dielectric that surrounds the conductors is the air...
  3. B

    B Multiple Curves in Space-Time: Masses on a Trampoline

    When you put a mass on a trampoline it causes the trampoline to V. If you put another similar or same sized mass on the same trampoline at a great enough distance, will the curve on the trampoline/space-time look like a W or a U ? If you can get the curves on a trampoline/space-time to look...
  4. M

    Python How to compute the percentage of values based on multiple columns

    I have a dataframe as shown in the picture and what I am trying to do is to calculate the number of occurrences based on the values in 2 columns and then calculate the percentage of the occurrences. I have tried the following code but it gives me a zero value in the end and i don't know why...
  5. M

    Is (3/4)*(a^2/c) less than a with multiple inequalities?

    Homework Statement I for some reason can't seem do become sure of this. There are 2 variables x and y. And two constants, a and c, which are both positive. Homework Equations x+2y ≤ (3/4)*(a^2/c) x + 2y < a The Attempt at a Solution Does this mean that: (3/4)*(a^2/c) < a ? Mons
  6. A

    MHB Reference request for self-studying multiple Riemann integrals

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  7. S

    MHB Calculating overall percentage/probability from multiple categories?

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  8. A

    I Identity Operator for Multiple Particles

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  9. Krushnaraj Pandya

    Analyzing a circuit with multiple batteries

    Homework Statement Find charge on 3 capacitors. Join two squares with one common side. At the middle of the common edge, place C3=6uF (micro-farad). On upper edge of left square, place C1=2uF. On upper edge of right square place C2=4uF. On lower edge of left square, a battery-10V and on lower...
  10. R

    How do I stop multiple radio frequencies ....Micro, Infra an

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  11. Alex Petrosyan

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  12. Grey Area

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  13. P

    Multiple processes interpretation

    Hi pf, there was an article in the Stanford encyclopedia about QM that was rewritten. it quoted a "multiprocess" interpretation differing from Everett's one which could be related to Bohm's interpretation. it is no more there. i am wondering if there are interpretatins where different results...
  14. Sophrosyne

    B How does the ear distinguish multiple different pitches?

    A chord played on a piano is multiple different pitches, each at a different frequency, played simultaneously. The ear hears this as separate sounds. The cochlea of the ear is organized by tone (tonographic organization), from highest to lowest frequency. So a triad chord will stimulate three...
  15. mishima

    I Test for dependence/independence of multiple variables

    I don't think this is related to linear dependence/independence of linear algebra. I am talking about multi-variable calculus. I am getting confused with being able to quickly tell which variables depend on others when there are 4+ variables involved. For example, suppose I have w(r,s)...
  16. E

    I Helmholtz resonator with multiple necks--formula?

    Does anybody happen to know the formula for resonant frequency of a Helmholtz resonator having N necks? Physics is not my field and I'm a bit over my head. I need the formula for a computer program related to musical instruments--this is the only thing holding me up. It seems like it would...
  17. M

    MHB Explore the Multiple Grid Method: Get Accurate Solution Faster

    Hey! :o I am trying to understand the multiple grid method. The idea is to use at each step different grids to solve a linear system of differential equations, so that we get the best approximation as possible. It holds that the finer the discretization, the more accurate the solution ist...
  18. PeterDonis

    A Does the MWI require "creation" of multiple worlds?

    From another thread: I see this claim made fairly often, but it does not seem correct to me. According to the MWI, the dynamics of the wave function is always unitary (there is no collapse), and a unitary process cannot "create" or "destroy" anything. All it can do is entangle things. So, for...
  19. D

    How Should Significant Figures Reflect Measurement Uncertainty?

    1. A student measures the density of a metal and calculates answer to be 8543.2kgm^-1 . The result is accurate to +- 1.1% Which of the following states answer to an appropriete number of sig figs? A 8.543x10^3 B 8.5x10^3 C 9x10^3 D 8.54x10^3 2. Relative Uncertainty = Absolute Uncertainty/...
  20. Pencilvester

    I Number of Geodesics Between Two Points: Topology vs. Homeomorphism

    In general, is the number of distinct geodesics between two fixed points purely a feature of the topology of the manifold? i.e. Can there ever exist two topologically equivalent (I can’t remember the proper word right now- is homeomorphic the right one?) manifolds, ##\mathcal M## and ##\mathcal...
  21. EF17xx

    Standing wave in a tube -- multiple choice question

    Homework Statement The correct answer according to answer sheet is answer B. Homework Equations λn= 2L/n (both ends open) λn = 4L/n (one end open one end closed) c=λf Speed of sound does not change. as it is still in air... (correct assumption? ) The Attempt at a Solution f1= 500Hz L =...
  22. EF17xx

    Why is D the correct answer for this multiple choice question?

    Homework Statement Homework Equations Fnet= Δp/Δt p=mv The Attempt at a Solution p (before) = 0.4 x 5 = 2 p (after) = 0.4 x 3 = 1.2 Δp = 0.8 Δt = 0.2 Fnet= Δp/Δt 0.8/0.2 = 4N Correct answer in textbook is D, I do not understand why?
  23. alijan kk

    Complex number multiple choice

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  24. Z

    Impulse: multiple choice question

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  25. Y

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  26. Buckethead

    B Spiral galaxies: Multiple axies of rotation?

    Spiral galaxies of course rotate around one axis perpendicular to the plane, but has anyone measured if any spiral galaxies are also rotating about an axis through the plane or about any other axis?
  27. J

    Heat Transfer through multiple walls

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  28. B

    MHB Predicate logic with multiple quantifiers

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  29. Jonathan Scott

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  30. Observeraren

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  31. Jay1298

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  32. C

    I Time Delay on Multiple Photons when travelling from one plac

    I'm trying to understand the time delay induced on each photon when several individual photons travel in an open space from a sender to a receiver for example in the application of Quantum Key Distribution. So what I understand so far is light(photon) travel around 299,792 km (186,282 miles) per...
  33. Prof. 27

    System.Threading Multiple Timers in C#

    Homework Statement Basically I'm trying to create two timers using System.threading.timer that run in parallel. One that runs for a minute, one that runs for a second. When I run the program I get nonsensical output. Despite reading a lot of stack overflow questions I can't seem to find where...
  34. I

    MHB And rule for multiple selections

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  35. B

    Electric field in a capacitor with multiple dielectrics

    Hi, I am trying to understand capacitors and have come across the example in the attached image. What I would like to understand is how to calculate the electric field at some distance x within the capacitor. With x>>R , x<R and x=R . The image is of two circular disks as the...
  36. Wookbert

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  37. paulo84

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  38. R

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  39. J

    How Do Non-Magnetic Metals React to Magnetic Fields?

    Homework Statement More than one options may be correct . Homework EquationsThe Attempt at a Solution [/B] Options a) and c) are correct . But I don't understand how non magnetic metal reacts to the magnetic field . Is it in some way related to ferromagnetism ? But then either both b)...
  40. J

    AC circuit Multiple choice question

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  41. Y

    Angular momentum multiple choice question

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  42. K

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  43. mfb

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  44. ang__

    How Do You Calculate the Total Inertia Matrix for a Composite Object?

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  45. D

    Centering a Laser Beam received from multiple directions

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  46. A

    I Can a supernova produce multiple stars?

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  47. R

    Integrating Multiple Solid Volumes: xy-Plane, x=1, x=3

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  48. C

    MHB What is an Integral Multiple of 4?

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  49. P

    Optimal Path from source to multiple destinations

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