What is Multiple: Definition and 1000 Discussions

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.

View More On Wikipedia.org
Recent contents Top users
  1. D

    Integral for Multiple Natural Logs

    Homework Statement I need to find whether or not the Ʃ1/(n(ln n)(ln(ln(n)))) (from 2 to infinity) converges or diverges using the Integral test. I think the best question to ask is where to start with the integral? Homework Equations None. The Attempt at a Solution I've...
  2. Angelos K

    Multiple images in gravitational lensing

    Dear all, so far I have only studied weak lensing. Therefore I understand little about multiple images.The light paths, by Fermat's principle, have to correspond to stationary points of the (proper) time delay. Minima, maxima saddle points. Basics are nicely reviewed here [p.14]...
  3. S

    Quantum Mechanics: Multiple Pathways Explained

    I recently got a starter home learning course on quantum mechanics and well its basically at the stage of explaining the simplistic basics of it. Now one part of the lecture video mentions that if a photon has two possible pathways it can take. They cancel each other out and there for it...
  4. C

    Solving a system of ODE with multiple 'time' variables

    Homework Statement Hi everyone, Consider the following system of (first order) differential equations: \dot{x}=f(t_1,x,y,z) \dot{y}=g(t_2,x,y,z) \dot{z}=h(t_3,x,y,z) where \dot{x}=\frac{\partial x}{\partial t_1}, \dot{y}=\frac{\partial y}{\partial t_2}, and \dot{z}=\frac{\partial...
  5. J

    Forces on multiple cylindrical magnets stacked

    I am trying to calculate the forces between ten small cylindrical magnets stacked (inside a tube so they cannot flip/shift) so that consecutive magnets are repelling. The bottom magnet is attatched to the bottom of the tube with, let's say, the positive pole facing up. Then the second has a...
  6. M

    Question about repeated measures Anova and multiple regression

    This is for my coursework. I have two problems. The first one. Homework Statement I have two time messures. Before and after a scheme was introduced.I have to answer a question if it made a statistically significant difference or not. And also as it was introduced in 3 places I need to...
  7. I_am_learning

    Multiple Choice Question negative marking

    You attend a multiple choice question exam, and you have n (say 10) questions whose answers you don't know at all. There are 4 choices in each question. A correct answer yeilds 1 marks. An incorrect answer has penalty of -0.25 marks. Is it wise to attempt all the questions in random? It...
  8. D

    Exploring Multiple Stieltjes Integrals and Their Generalizations

    I'm studing the Riemann-Stieltjes integral \int_a^b f dg on closed intervals [a,b] of the real line, and the natural question came to me: How would a multiple R-S integral be defined, say, on some set D \subset \mathbb{R}^2 ? Would one use some kind of two variable integrator function...
  9. C

    Multiple questions, , test friday

    Hi. I have a test on friday, and I was given a sheet to review. However, many of these questions I have no clue how to answer, as my teacher never went over them. I'd really appreciate a step by step walkthrough on how to do the problems, as I don't want the answers, I want to know how to...
  10. S

    Is there such a thing as an indefinite multiple integral?

    A calculus book I am looking at ("Early Transcendentals") does not seem to mention it, but it seems like it is possible, with the constants of integration being functions that have no component in variable being used for the integration. Any insight? Articles?
  11. T

    Taking Multiple Surface Integrals

    Homework Statement http://img687.imageshack.us/img687/1158/skjermbilde20111204kl85.png The Attempt at a SolutionI thought this was pretty hard and involved a number of different parts. Here's my work: Let x=cosθ and z=sinθ, also let 0≤y≤2-x=2-cosθ. I parametrize Q1, which I define to be...
  12. L

    Do we see multiple images in mirror?

    When we look at a mirror we see our image but the light that reaches our eyes also reflects off our bodies back to the mirror again and back to our eyes. Do we see multiple images of our self but somehow ignore all but the primary reflection?
  13. N

    Impulse Multiple choice question

    Homework Statement In a collision between two unequal masses, how does the impulse imparted to the smaller mass by the larger mass compare with the impulse imparted to the larger mass by the smaller one? A) It is smaller. B) The answer depends on how fast they are moving. C) They are...
  14. N

    What Defines the Properties of All Electromagnetic Radiation?

    Homework Statement which are properties of all Electromagnetic radiation I the travel at the speed of light in space II they propagate through the creation of mutually perpendicular electric and magnetic fields III they are constant and do not vary with time IV they have the same frequency and...
  15. S

    Is it possible to use multiple network adapters at the same time?

    My current problem: I have a machine sending a file every few seconds over its wired connection. While this is occurring, I want to be able to access a wireless network and download a file from a mapped network drive without interrupting the aforementioned file transfers. Any suggestions as...
  16. W

    Multiple eigenvalues - any hints would be appreciated

    Homework Statement I need to prove that a 4x4 matrix has 2 zero eignenvalues. 2. The attempt at a solution I have tried to obtain the characteristic equation but calculating the determinant of a relevant 4x4 is rather daunting as there aren't many zeros. I was wondering if there is...
  17. R

    Having trouble with this multiple integral question

    Homework Statement Given a point P(x,y,z) in a three-dimensional space, let P' denote the projection of P onto the xy-plane and let O denote the origin of the coordinates, and define f(x,y,z) as the area of the triangle. Compute: Integral of the Integral of the Integral of f(x,y,z) under...
  18. R

    Special Relativity: Multiple FoR

    Homework Statement A train of length 15 cs* moves at speed 3c/5. 39 How much time does it take to pass a person standing on the ground (as measured by that person)? Solve this by working in the frame of the person, and then again by working in the frame of the train. *cs stands for...
  19. S

    Multiple Integrals for Functions Unbounded at Isolated Points

    In a recent homework assignment, I was asked to prodive a definition for ∫f(x) in the Region D, provided there was a discontinuity somewhere in the region. To define the integral, we merely removed a sphere centered on the discontinuity of radius δ>0 and found the limit of the integral as δ→0...
  20. F

    Can collision of two protons create multiple antiprotons ?

    collision of two protons at about 1.8 Gev results in p + p --> p + p + p + p* will collision at an energy of 3.6 Gev result in p + p --> p + p + p + p + p* + p* if not what else happens ?
  21. T

    Multiple problems dealing with springs and Hooke's Law

    Homework Statement A vertical ideal spring is mounted on the floor and has a spring constant of 132 N/m. A 0.80-kg block is placed on the spring in two different ways. (a) In one case, the block is placed on the spring and not released until it rests stationary on the spring in its equilibrium...
  22. A

    How air molecules still carry acoustic messages when multiple sources present?

    We know that air molecules are subjected to random motion in different directions. A sound wave is a push toward these molecules to make a wave front to make them expand or contract in groups so that we can hear a voice message in our ears. The question is that what happens when different...
  23. N

    When to assign a value to a multiple chain derivative?

    I was doing my homework and I ran into a problem of a chain rule within a chain rule. When do I know what to assign a value? For example: y=e^{-x^2} When I assign u=e^{-x} and y=u^2 I get a wrong value. According to cramster I was supposed to assign y = e^u and u=-x^2. But when am I supposed...
  24. C

    Mixing chamber with multiple inlets

    Hi I was wondering if someone could help me with this question. Question 4 uploaded in picture. Ok, so far this is what I have found Pipe 1: m1=2kg/s P1=1000kpa T1=100 C h1=334.82kJ/kg Pipe 2: sat-liquid T2=60 C P2= 1000kpa h2=291.36KJ/kg Outlet: sat vapor P3=1000kpa V=20...
  25. T

    Multiple Spring Deflection Question

    I need a little help in figuring out spring rates for a system I'm working on. I'll try to describe it as best as possible: I want to lower a growing stack of material (tubes) from an elevation to the floor. As more tubes are stacked, more weight is added to the system and the load lowers...
  26. W

    Comparing Potentials of Multiple Charges at Varying Distances from the Origin

    Homework Statement Charge Q is located at the (x,y) origin. q is a distance r in the +x direction from Q. 2q is a distance 2r in the +x direction from Q. Which of q or 2q is at a higher potential? q, 2q, or same. The Attempt at a Solution I am thinking that it would depend on Q. Q=0, then...
  27. Q

    What is the Velocity of Point P in a Multiple Pulleys System?

    Homework Statement The block B moves to the right with a constant velocity of 30 cm/s. Given this, which of the following is correct: 1. Speed of block A is 15 cm/s 2. Speed of point P is 60 cm/s 3. Speed of point P is 30 cm/s 4. Speed of block A is 40 cm/s Homework...
  28. M

    Engineering Circuit network with multiple ports

    Find V2/V1 for the network below: What I did was try to solve by reducing to thevenin equivalents for V1 and V2 separately For V1: I got Vth = V1 Zth1 = 41/15 V1 = I1*(41/15) For V2: I got Vth = V2 ...but I am having trouble trying to find the Zeq2: I know once I find that V2 = I2*Zeq2 and...
  29. B

    Limits of multiple variables along y=mx

    This is an assignment problem I have. Can't seem to figure it out. It has two parts, one to prove that the function approaches 0 where y=mx and and one where the function approaches 0 from y=kx2... f(x,y) = (x3y)/(2x6+y2) I've attempted both parts and get stuck on what seems like the same...
  30. E

    Multiple Pullys and determing Tension

    Multiple Pulleys and determing Tension Dynamics So i started out with the the equation for the tension of the block-pulley system on the far left in the y direction being: 2T-2g = 2*a1 the equation for the middle block-pulley system is: 2T-2g = 3*a2 the equation for the block on the ramp is...
  31. R

    Multiple variable correlation - drowning in stats formulas,

    Hello everyone, My boss has asked me to find if there is any correlation between various sample parameters in a water quality study. We took around 150 samples, and for each one measured around 50 parameters e.g. iron content, free residual chlorine, level of coliforms, pH, etc etc. I...
  32. F

    Multiple Pulley/Friction system

    Multiple Pulley/Friction system Please Help! Homework Statement In the given figure, the coefficient of kinetic friction between the two blocks shown is 0.30 a) Assume that the surface of the table and the pulleys are frictionless. Determine the acceleration of each block and the tension...
  33. V

    Kinematics with multiple objects

    Homework Statement Mike is standing below a tower. His friend on top of the tower which is 580 m drops a balloon at him. At the instant mike fires a potato from a cannon moving at an initial velocity of 95 m/s. How long does it take for the balloon and potato to collide? Homework...
  34. V

    Kinematics with multiple objects

    Homework Statement Mike is standing below a tower. His friend on top of the tower which is 580 m drops a balloon at him. At the instant mike fires a potato from a cannon moving at an initial velocity of 95 m/s. How long does it take for the balloon and potato to collide? Homework...
  35. B

    Multiple integral change of variables

    Let R denote the region inside x^2 + y^2 = 1 but outside x^2 + y^2 = 2y with x=>0 and y=>0. Let u=x^2 + y^2 and v=x^2 + y^2 -2y. Compute the integral of x*e^y over the region D in the uv-plane which corresponds to R under the specified change of coordinates. I'm having trouble with this one...
  36. R

    Effective Focal Length of Multiple Lenses

    In my Optics book (Hecht, 4th edition) the author discusses how, when dealing with a multiple lens system (say, with n many lenses), one can think of the system as a single lens system, with an effective focal length given by: 1/f(effective) = 1/f1 + 1/f2 + ... + 1/fn My question is this...
  37. M

    Multiple choice question involving conservation of energy on inclined planes

    Homework Statement You have a pair of inclined planes such that a block that slides down one can slide up the other without losing any energy in the transition. The inclined planes are both at an angle θ from the horizontal, as shown in the diagram. The inclined plane on the left is...
  38. J

    Gravitational forces and multiple bodies problem

    Homework Statement Four 335 kg spherical masses are placed on the corners of a square at coordinates (0, 0), (0, 1.50), (1.50, 0) and (1.50, 1.50) where all coordinates are in meters. What is the net gravitational force on the mass at (0, 0) due to the other three masses? Express your answer...
  39. S

    MATLAB Matlab m file function with multiple variables

    Hi, I have a MATLAB function m file and I want to integrate the function. function y = myfun(t,a,b) y = (1/(2*pi)).*(1./t)*(1i*(a+b)); endThen when I call the integration in MATLAB I don't know how to specify a and b whilst integrating over t. I need to be able to set a and b outside of the...
  40. S

    Multiple events and using bayes theorem

    I am not sure if I am doing this correctly, so please check my attempt: I have four discrete random variables: G, H, J, L Say, I want to find P(H|J, G, L). Then can I write as P(H|J, G, L) = P(J, G, L|H)*P(H) = P(J|G, L, H)*P(G|L, H)*P(L|H)*P(H) Are those equivalent? I can't find an...
  41. B

    Does Palladium and Sulfur Demonstrate the Law of Multiple Proportions?

    Homework Statement The Problem goes as follows: Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below: Compound Grams S per Gram Pd A 0.603 B 0.301 C 0.151 Show that these...
  42. N

    MATLAB How to plot multiple iterations of a while loop on one plot? [MATLAB]

    If I want to plot multiple iterations of a while loop on one plot, how can I do that? Every time I use "hold on", it just distorts the original line after every iteration instead of drawing independent lines. Please help
  43. J

    How to Find the Variance of O hat1 in a Multiple Regression Model?

    Consider the multiple regression model containing three independent variables y = B0 + B1x1 + B 2x2 + B 3x3 + u You are interested in estimating the sum of the parameters on x1 and x2; call this O1 = B1 + B 2 a) Show that O hat1 = B hat 1 + B hat 2 is an unbiased estimator of O1. b)...
  44. J

    Multiple regression analysis, econometrics, and statistics

    I am sooo lost in this class, please help. 1. Let the true (population) model be y = B0+B1x1+B2x2+u where u is an unobserved error term with u (conditional) x1, x2 and N(0, sigma^2). Hence, u is normally distributed with mean 0 and variance sigma^2 (i.e., E[u (conditional) x1, x2] = 0 and V...
  45. P

    How retrieve multiple information by a single number?

    I was wondering how they did come up with the way of setting permissions using the linux program chmod by just using numbers. For example: 1 is for execute 2 is for write 4 is for read Any sum of those give a unique permission to a file: 2+4=6 Let's you write and read it. 1+4=5 Let's you...
  46. T

    Fortran [FORTRAN] Writing to same file from multiple processors?

    I am working in FORTRAN I need to avoid writing to the same file at the same time while working in a parallel environment. I have a program (that I have not written and cannot edit) that calls a subroutine (that I have written and can edit). The subroutine is called over and over again by...
  47. M

    Probability in a multiple choice test

    Two students are taking a 10 question test. Each question has 4 different answers. How many ways can each student answer the test? What is the probability that these two students get the same answers? I know that to get the number of ways to answer, the number of students is irrelevant. nk...
  48. O

    Comparing mass ratios and 'proving the law of multiple proportions holds true'

    Compare the mass ratios of N2O3 and N2O5 and prove the law of multiple proportions holds true. I'm having trouble understanding what the question is asking for. So far, I've done this: N2O3: N: 14g * 2 = 28g O: 16g * 3 = 48g N2O5: N: 14g * 2 = 28g O: 16g * 5 = 80g...
  49. D

    Time constant of a thermal model with multiple masses and units

    Hi, i have modeled a thermal system in simscape: the unit includes a polymer casing inside which there is a heater, heat spreader and a fluid sample in that order. i wish to validate this model by hand calculations such as finding the time constant. However i do not know how to find the time...
  50. F

    Understanding Multiple Delta Function in 1D and Multidimensional Spaces

    Hi everyone, I have trouble understanding the multiple delta function. For one dimensional delta function, we have δ(\varphi(x))=\sum_{i=1}^{N}δ(x−xi)|\varphi′(xi)| where xi's (for i = 1 to N) are simple zeros of f(x) and it is known that f(x) has no zeros of multiplicitiy > 1 but...
Back
Top