What is Unit: Definition and 1000 Discussions

UNIT is a fictional military organisation from the British science fiction television series Doctor Who and its spin-off series Torchwood and The Sarah Jane Adventures. Operating under the auspices of the United Nations and initially led by Brigadier Lethbridge-Stewart, its purpose is to investigate and combat paranormal and extraterrestrial threats to Earth. Several UNIT personnel (such as the Brigadier, Sergeant Benton and Mike Yates) played a major role in the original Doctor Who series, and it was a regular feature from The Invasion (1968) until The Seeds of Doom (1976).
Originally referred to as the United Nations Intelligence Taskforce, executive producer Russell T Davies said in 2005 that the UN was no longer happy to be associated with the fictional organisation and the UN's full name could now no longer be used. However, the "UNIT" and "UN" abbreviations could be used as long as it was not explained what the letters stood for. In 2008, he announced that the organisation's name had been changed to the Unified Intelligence Taskforce. This new name was first mentioned on-screen in "The Sontaran Stratagem", also in 2008, in which it was indicated in a line of dialogue that the United Nations still supports UNIT with funding.

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  1. R

    How to Correctly Convolve x[n] with a Unit Step Function?

    Homework Statement Find convolution of x[n] (graph in attachment) and h[n] where h[n] = u[n] Homework EquationsThe Attempt at a Solution - flipped the h[n] to have h[-n] - moved to the left once (h[-1-n]) to align - multiplied h and x and it gives me all zeros Is this correct or I'm missing...
  2. J

    MHB Attributing Difference in Unit Margins to Regions

    There are three regions: East, West, and Central. Each region has dollars, gallons, and dollars per gallon. There are forecasted numbers as well as actual numbers. East - Forecast - USD50,000; 1,200 gal; USD41.67/gal West - Forecast - USD75,000; 1,700 gal; USD44.12/gal Central - Forecast -...
  3. J

    Resolving vectors into a unit vector

    Homework Statement electric field polarization for a given antenna is expressed as: E_i = (a_x + a_y) E (r, theta, phi) The unit vector along the antenna polarization is found as u_a = 1/Sqrt(2) (a_x + a_y)2. Question Where/how is the 1/Sqrt(2) found to resolve those other 2 vectors into a...
  4. M

    How many liters of shot does Ben need to carry out his demonstration?

    Homework Statement During the Cold War the US and the former Soviet Union built up enormous arsenals of nuclear weapons. Although the exact amounts are not known, particularly for the USSR, the stockpile of the US arsenal alone is knowledgeably estimated to have a total destructive power of...
  5. R

    A vector F=Fz, where z is unit vector, expressed in sphereical coord.

    Homework Statement So the full problem reads: A vector F has the same magnitude and direction at all points in space. Choose the z-axis parallel to F. Then , in Cartesian coordinates, \vec{F}=F\hat{z}, where \hat{z} is the unit vector in the z direction. Express \vec{F} in spherical...
  6. deedsy

    Deriving sin(a-b) trig identity using Cross Product of Unit Vectors

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  7. K

    Can somebody figure out which unit this should be?

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  8. C

    Answer Checking: Unit 1 Waves Chapter 1

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  9. T

    Define boundary conditions of a polygon in a unit square cell

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  10. L

    Is There a Connection Between Inequality and the Unit Disc?

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  11. H

    Determination of atomic bases in unit cell using Wien2k

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  12. M

    Riemann curvature of a unit sphere

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  13. ZetaOfThree

    Second derivative of a unit vector from The Feynman Lectures

    In the Feynman Lectures on Physics chapter 28, Feynman explains the radiation equation $$\vec{E}=\frac{-q}{4\pi\epsilon_0 c^2}\, \frac{d^2\hat{e}_{r'}}{dt^2}$$ The fact that the transverse component varies as ##\frac{1}{r}## seems fairly obvious to me since what matters is just the angle...
  14. S

    Derivative of a rotating unit vector

    I think this is a textbook-style question, if I am wrong, please redirect me to the forum section where I should have posted this. This is my first time here, so I am sorry if I am messing it up. Homework Statement We have an n-dimensional vector \vec{r} with a constant length \|\vec{r}\|=1...
  15. M

    Time and matter, is there a smallest unit?

    dear friends, I have always wonder: is there a smallest unit for time and matter? or in other words, can we continuesly divide time and matter into smaller pieces non-stop? ive had this question since young when I imagined myself cutting a piece of cheese. I just can't help stop cutting it and...
  16. steve_h

    Silicon carbide polytypes (large unit cells)

    Hello everyone. I am a Hungarian born Australian theoretical/applied physicist. This is my first post on the forums. I am aware that silicon carbide crystal occurs in many different crystalline forms. I was wondering if someone here could please point me to a source that catalogs the...
  17. S

    How to measure angular velocity and what is the unit of angular veloci

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  18. hagobarcos

    Unit Vector Problem: Find Point of Intersection

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  19. Ackbach

    LaTeX Best Unit Vectors in LaTeX for TeX.SE Interaction

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  20. hagobarcos

    Simple Unit Vector Problem Part 2

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  21. hagobarcos

    Simple Unit Vector Problem: Finding Parallel and Perpendicular Vectors

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  22. D

    Converting MPa·mm1/2 to MPa.m1/2: A Scientific Approach

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  23. F

    Potential Energy Stored in Hydrostatic Test Unit

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  24. K

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  25. G

    Discretization in cylindrical coordinates, unit thickness for azimuth?

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  26. T

    EMU sensitivity unit for SQUID magnetometers

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  27. powerof

    Help with matrix form of the imaginary unit, i

    While investigating more about complex numbers today I ran across the 2x2 matrix representation of a complex number, and I was really fascinated. You can read what I read here. As I understand it, you write z in its binomial form but instead of "1" you use the identity matrix, I, and for i...
  28. M

    Relation between unit tangent/normal vectors, curvature, and Lin. Alg.

    Hey there, This isn't a homework question, it's for deeper understanding. So I'm learning about unit normal/tangent vectors and the curvature of a curve. I have a few questions/points. 1) So my book states that we can express acceleration as a linear combination of the acceleration in the...
  29. L

    Automorphisms of the unit disc is less than 1

    I want to show that the modulus of the automorphism \frac{a-z}{1-\overline{a}z} is strictly bounded by 1 in the unit disc. Applying Schwarz lemma gives the result immediately. But I am looking for a straight forward proof for that. Thanks in advance
  30. A

    How to manage a protection unit under a power plamt

    As an Electrical Engineer, I am employed in a Power company. In this company, they want to create a unit for Protection which cover for both the Generation Department and the Transmission & Distribution Deparment. This is my 3rd month in the company. I was advised to make a plan on how to...
  31. G

    Confusion of the electrical conductivity unit in CGS.

    Hello. Electrical conductivity is written as \frac{n_{e}e^{2}}{m_{e}\nu_{ei}} where n_{e}, e, m_{e} and \nu_{ei} are for electron density, charge, mass and electron-ion collision frequency. According to Wikipedea, http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity Unit...
  32. G

    Unit conversion problem for the electron thermal conductivity

    Hello. In CGS unit electron thermal conductivity for plasma is expressed as \frac{n_{e}T_{e}}{m_{e}\upsilon_{e}}\Gamma_{1} [1] where \Gamma_{1} is the dimensionless transport coefficient. [2] You can also find similar expression in...
  33. J

    Is There a Formula for Unit Eigenvectors?

    I never see before a formula for a eigenvector, however, given a generic matrix (http://www.wolframalpha.com/input/?i={{A%2C+B}%2C+{C%2C+D}}) the wolfram is able of find the eigenvectors... So, exist a formula for the unit eigenvectors?
  34. U

    Simple Calculation of Astronomical Unit Problem

    Homework Statement The period of Mars is 1.881 years. When Mars is opposite the Sun in the sky, its position with respect to the background of fixed stars is measured at sunset and again at sunrise. The effective baseline between the two positions is 11,700 km and the change in position on the...
  35. W

    How to estimate 2 points on the unit circle

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  36. C

    First order unit step response

    I think I mostly understand how this works, and it makes intuitive sense. However, I'm a little bit confused by one step in the proving of this. On the second page of the attached PDF, there is this statement: x' + kx = (r/k + c2)δ(t) ... (followed by the cases of t<0 and t>0 What comes...
  37. J

    Bel is unit for what physical quantity?

    If Newton is unit for measure force, meter is unit for measure length and radian is unit for measure angle, so, bel is unit for measure which physical(/mathematical) quantity?
  38. G

    Can equilibrium rate constant has unit of [time^-1]?

    Hi all, I am having a homework problem that is statement really bothers me and I think it might be a typo. It goes in the following: Homework Statement A is a short life unstable state and it is in equilibrium with B and C. A\LeftrightarrowB A\LeftrightarrowC The equilibrium rate constants...
  39. T

    How do I identify the unit from the question?

    EXAMPLE QUESTION: Calculate the mass per unit length of the wire, μ, given by μ = g /(2fG)^2 where g = 9.81 N kg–1 and f = 50 Hz. For example here is it mass per unit length and so would it be kg/m? It kg/m the same as kgm^-1. But then how do I identify the units like kgm^-2 like how...
  40. L

    Understanding MEMS Accelerometers: Converting and Integrating Data

    I am bit confused on the units when you convert acceleration to displacement. The accelerometer data is in bits. I can convert this to gs or milli gs. When integrating, this will get multiplied by millisecs. What will the displacement unit be in?
  41. M

    Example about tangential and normal unit vectors

    Here is a example 1.3 from analytical dynamics of Haim Baruh. a particle moves on a path on the xy plane defined by the curve y=3*x^2 , where x varies with the relation x= sin(a). find the radius of curvature of the path and unit vectors in the normal and tangential directions when a=pi/6...
  42. J

    Unit Conversion W➝J: Break-Even in 50 Years?

    Homework Statement Effective Power generation of the plant is 5.43*10^{7}W but it will required 9*10^{16}J to be created. Essentially the break-even will after solving equation Energy required/Power Generated however I get results of almost 50 years. Would this be correct...
  43. R

    How to get the volume per atom when given the unit cell size?

    1. estimate the fermi energy for lithium... the crystal structure of lithium is a bcc with a unit cell size of 3.5*10^-10 m [b]i need n, which equals N / V. if i divide by per atom, then i get (N/atom) / (V/atom) = valance / (V/atom). my question is how to get the volume per atom...
  44. E

    Dot Product of a Unit Vector with the Negative of itself

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  45. N

    Why does the unit vector r-hat always point away from a charge?

    In my textbook, it states that given q1 and q2 where both charges are positive and of equal magnitude, the unit vector r-hat always points away from q1. Why is this so? What if both charges are of opposite charge? Does r-hat still points away?
  46. F

    Integration including unit vectors

    I have an integral of aΘ cos(Θ) dΘ a is the unit vector for Θ. I'm not sure what to do with it in the integration. I know the unit vector equals a/abs(a) but that would give a mess of an integral cause of the abs(a).
  47. nomadreid

    States are or aren't unit vectors?

    I am a little confused by an elementary point. Something must be wrong with the following: On one hand, a Hermitian operator (which is not necessarily unitary) takes one state to another state. Hence a state need not be represented as a unit vector; its norm can be greater (or less than)...
  48. S

    Integrate complex function over unit circle

    Homework Statement Calculate ##\int _Kz^2exp(\frac{2}{z})dz## where ##K## is unit circle.Homework Equations The Attempt at a Solution Hmmm, I am having some troubles here. Here is how I tried: In general ##\int _\gamma f(z)dz=2\pi i\sum_{k=1}^{n}I(\gamma,a_k)Res(f,a_k)## where in my case...
  49. D

    Last edited by a moderator: May 6, 2017

    Hello Homework Statement Show that for an ideal gas: n(E)dE=2πn/(kπT)3/2 *E1/2 exp(-E/kT) dE where n(E) is the number of particles for each element of volume whose energy is between E and E+dE Homework Equations The Attempt at a Solution Really don't know where to start...
  50. JasonHathaway

    Unit vectors in different coordinates

    Hi everyone, I've some points I want to make sure of. 1- When converting a "POINT" from a coordinate system to another, I'll just use the derived equation to convert (e.g. (1,2,3) from cartestian to cylindrical: \rho=\sqrt{x^{2}+y^{2}}, \phi=tan^{-1}\frac{y}{x}, z=z 2- When converting an...
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