Vectors Definition and 1000 Threads

In mathematics, physics and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) is a geometric object that has magnitude (or length) and direction. Vectors can be added to other vectors according to vector algebra. A Euclidean vector is frequently represented by a ray (a directed line segment), or graphically as an arrow connecting an initial point A with a terminal point B, and denoted by






A
B






{\displaystyle {\overrightarrow {AB}}}
.A vector is what is needed to "carry" the point A to the point B; the Latin word vector means "carrier". It was first used by 18th century astronomers investigating planetary revolution around the Sun. The magnitude of the vector is the distance between the two points, and the direction refers to the direction of displacement from A to B. Many algebraic operations on real numbers such as addition, subtraction, multiplication, and negation have close analogues for vectors, operations which obey the familiar algebraic laws of commutativity, associativity, and distributivity. These operations and associated laws qualify Euclidean vectors as an example of the more generalized concept of vectors defined simply as elements of a vector space.
Vectors play an important role in physics: the velocity and acceleration of a moving object and the forces acting on it can all be described with vectors. Many other physical quantities can be usefully thought of as vectors. Although most of them do not represent distances (except, for example, position or displacement), their magnitude and direction can still be represented by the length and direction of an arrow. The mathematical representation of a physical vector depends on the coordinate system used to describe it. Other vector-like objects that describe physical quantities and transform in a similar way under changes of the coordinate system include pseudovectors and tensors.

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  1. BradC

    Deriving Massive spin 2 propagator from polarization vectors

    In A. Zee "QFT in a nutshell" in chapter I.5 Exercise 1.5.1 on page 39 for spin 2 massive propagator. I know I’m missing something very simple (self-taught beginner). I'm trying to derive equation (13) on page 35, which is G_{\mu\nu,\lambda\sigma} = G_{\mu\lambda}G_{\nu\sigma} +...
  2. J

    Quantum states as normal vectors

    Are all quantum states represented by normal vectors?
  3. A

    Given two vectors, find vector of the parallelogram height

    Homework Statement Find the coordinates of the vector of the height of the parallelogram formed by vectors a={1, 2, 1} and b={2, -1, 0} Homework Equations A=|axb|, A=|a|*h The Attempt at a Solution I can find the intensity of the vector h i.e the length of the height, but not its vector. I...
  4. upwardfalling

    Adding Vectors Using the Component Method

    Homework Statement Use the component method to add the vectors vector A and vector B shown in the figure. The length of vector B is 3.25 m and the angle θ = 28.5°. Express the resultant vector A + vector B in unit-vector notation. Homework Equations x = rcos y = rsin The Attempt at...
  5. C

    Cartesian to polar unit vectors + Linear Combination

    I've been trying to solve this question all day. If somebody could point me in the right direction I would really appreciate it! (ii) A particle’s motion is described by the following position vector r(t) = 4txˆ + (10t − t)ˆy Determine the polar coordinate unit vectors ˆr and ˆθ for r. [4]...
  6. P

    Components of vectors (polar coordinates)

    I have always been under the impression that a vector is not "fixed" in space. Given any vector, we could just move it around and it would still have the same components (in a cartesian coordinate system). What confuses me, however, is how we define the components of a vector in polar...
  7. M

    MHB Three vectors are on the same plane

    Hey! :o We want to show that if $\overrightarrow{a}, \overrightarrow{b}, \overrightarrow{c}$ are on the same plane, then there are $A, B, C$ not all $0$ such that $A \vec a+B \vec b+C \vec c=\vec 0$. The solution is the following: If $\overrightarrow{a}, \overrightarrow{b}...
  8. Feodalherren

    MATLAB: Plot vectors from a function

    Homework Statement So I have a function that allows me to input two vectors and it will calculate the resultant vector. The code works fine. I need to call on this function and plot the two input vectors and the resultant; it's easier to explain if you look at the code. Homework EquationsThe...
  9. C

    Curves and tangent vectors in a manifold setting

    Consider the following definition: (##M## denotes a manifold structure, ##U## are subsets of the manifold and ##\phi## the transition functions) Def: A smooth curve in ##M## is a map ##\gamma: I \rightarrow M,## where ##I \subset \mathbb{R}## is an open interval, such that for any chart...
  10. V

    Velocity and acceleration vectors

    Question #7. It says: The (constant) acceleration points in the direction of the difference of the velocities (final minus initial). Note how initial vector is subtracted from the final one (head to tail). But in this video, average acceleration (change in velocity) is found by adding velocity...
  11. entropy1

    Why do ket vectors not have magnitudes?

    Why does the magnitude of a ket vector not matter? The motivation appears to be that a state vector only can decribe a particle, or no particle. But why shouldn't the magnitude of ket vectors not be used to represent the density of the particles, the average number of particles? I'm am fairly...
  12. P

    Best vectors for gene mapping (FISH)?

    If you were to have clones of genes you wished to use for FISH in the form of a plasmid, cosmid, BAC and YAC, which would be best for gene mapping? I'm unsure as to what the distinction would be between these types particularly for use in FISH. Which is most commonly used and why? Thanks
  13. D

    Why are vectors defined in terms of curves on manifolds

    What is the motivation for defining vectors in terms of equivalence classes of curves? Is it just that the definition is coordinate independent and that the differential operators arising from such a definition satisfy the axioms of a vector space and thus are suitable candidates for forming...
  14. J

    Discover Solutions for Vectors Cross Product Homework | AM x BC = AM x AC

    Homework Statement Find the set of points of M such that: AM x BC=AM x AC (Vectors) The Attempt at a Solution [/b] AM x (BM+MC) =AMx(AM+MC) AMxBM+AMxMC=AMxAM +AM x MC Then AMxBM=0 MA X MB=0 I am new to this lesson and this is my first time i solve such a question and i had no idea...
  15. D

    Tangent vectors as directional derivatives

    I have a few conceptual questions that I'd like to clear up if possible. The first is about directional derivatives in general. If one has a function f defined in some region and one wishes to know the rate of change of that function (i.e. its derivative) along a particular direction in that...
  16. A

    Does scalar multiplication affect the cross product of vectors?

    Mod note: Member warned about posting with no effort. 1. Homework Statement Expand to the general case to explore how the cross product behaves under scalar multiplication k (a x b) = (ka) x b = a x (kb). The Attempt at a Solution would this be the right general case to portray the situation?
  17. A

    Vectors Math Help (solution check)

    Homework Statement Use three specific vectors in 3 space to show that ⃗ a ×(b⃗ ×c⃗ ) ≠ (a⃗ ×b⃗ )×c⃗ solution is in pdf... Homework EquationsThe Attempt at a Solution
  18. A

    Using 3 Vectors to Show Vector Multiplication is Not Commutative

    Homework Statement That is, use three specific vectors in 3-space to show that...
  19. A

    What is the cross product of two vectors whose result is the zero vector?

    Homework Statement Verify (https://ucdsb.elearningontario.ca/content/enforced/4850117-BL_1415Sem2__MAT_MCV4UU-948314_1_ELO/MCV4UPU01/MCV4UPU01A06/images/vec-a.gif?_&d2lSessionVal=Y3hirJUTSYjH76OEZwqHIBATE&ou=4850117 +...
  20. B

    Proof of Distributive Property of Vectors

    Homework Statement Let u, and v be vectors in Rn, and let c be a scalar. c(u+v)=cu+cv The Attempt at a Solution Proof: Let u, v ERn, that is u=(ui)ni=1, and v=(vi)ni=1. Therefore c(ui+vi)ni=1 At this point can I distribute the "c" into the parenthesis? For example: =(cui+cvi)ni=1...
  21. M

    MHB How do vectors play a role in ship navigation?

    Hey! :o We suppose that a ship, that is at the position $(1, 0)$ of a nautical map (with the North at the positive direction $y$) and it "sees" a rock at the position $(2, 4)$, is directed to North and is traveling $4$ knots in the relation to the water. There is a current of 1 knot that is...
  22. H

    Find Magnitude of V1 X V2 When Vectors are Perpendicular

    Homework Statement V1 and V2 are different vectors with lengths V1 and V2 respectively. Find |V1 X V2| if V1 and V2 are perpendicular. Homework Equations V1 X V2 = |V1|*|V2|sin(Θ) The Attempt at a Solution Since sin(90) = 1, V1 X V2 = |V1|*|V2|. When I input this answer it says its incorrect...
  23. M

    MHB Plane that is constructed by vectors

    Hello! :o I found the following in my notes: The plane that is constructed by two non-parallel vectors $\overrightarrow{v}$ and $\overrightarrow{w}$ consists of all the points of the form $a \overrightarrow{v}+b\overrightarrow{w}$, $a, b \in \mathbb{R}$. The plane that is defined by...
  24. Calpalned

    Area of a triangle using vectors

    ## 1. Homework Statement Let P = (1,1,1), Q = (0, 3, 1) and R = (0, 1, 4). Find the area of triangle PQR Homework Equations ## \frac {|PQ × PR|}{2} ## = area (The crossproduct divided by two) The Attempt at a Solution I lost my answer key, so I want to check if my final answer of ## \frac...
  25. G

    Confused about vectors and transformations (linear)

    when we are talking about a linear transformation the argument of the function is a coordinate vector...is this true? another question...when i see a column vector...these are the coordinates of the vector with respect of a basis...is this true? for example if i see... (({{1},{3}}))^T with...
  26. J

    Velocity vectors in different directions for momentum

    Homework Statement I'm stuck on this problem, and I don't really know how to approach it. Homework Equations Pretty much just p=mv And the conservation of linear momentum: total initial mv = total final mv The Attempt at a Solution I tried just plugging in the variables into the...
  27. LiHJ

    Exploring Vectors and Similar Triangles: A Homework Challenge

    Homework Statement Dear Mentors and PF Helpers, Here's the question: Homework EquationsThe Attempt at a Solution Here's my solutions: Please let me know whether I'm right. Thank you [/B]
  28. D

    A question on defining vectors as equivalence classes

    I understand that a tangent vector, tangent to some point p on some n-dimensional manifold \mathcal{M} can defined in terms of an equivalence class of curves [\gamma] (where the curves are defined as \gamma: (a,b)\rightarrow U\subset\mathcal{M}, passing through said point, such that \gamma (0)=...
  29. D

    Direct Product of Two Spin-Up Vectors: What Is It?

    Hi I have just started looking at direct products and came across the following which i don't understand : the direct product of two spin -up vectors = | 1 > which is in a bigger vector space I don't understand how the direct product is | 1 > ? and in this case is it always a bigger vector...
  30. S

    Subscripts and superscripts in four vectors

    Homework Statement I'm having trouble with understanding four vectors in particle physics. I'm reading this wikipedia page,http://en.wikipedia.org/wiki/Einstein_notation, and its telling me that ## v^\mu= \begin{pmatrix} \mu_0 \\ \mu_1 \\ \mu_2 \\ \mu_3 \end{pmatrix} ## and ## v_\mu=...
  31. L

    Find Magnitude & Direction for acceleration

    Homework Statement Block B has acceleration of 4 m/s2... Relative acceleration of block A w/ respect to B is 4 m/s2. Find magnitude & direction of accel for A? Homework Equations a_A = a_B + a_A/B x_A = x_B + x_A/B y_A = y_B + y_A/B The Attempt at a Solution x & y components: -4cos(20) =...
  32. B

    Use vectors and the dot product to prove the midpoint

    Homework Statement [/B] Use vectors and the dot product to prove that the midpoint of the hypotenuse of a right triangle is equidistant to all three vertices. Homework Equations [/B] I know the dot product is A⋅B = |A||B|cosΘ ... or ... A1B1 + A2B2 + A3B3 ... + AnBn I know the...
  33. G

    Linking Fourier Transform, Vectors and Complex Numbers

    Homework Statement Homework EquationsThe Attempt at a Solution I tried to attempt the question but I am not sure how to start it, at least for part (i). My biggest question, I think, is how does the multiplication of a random complex number to a Fourier-Transformed signal (V(f)) have an...
  34. E

    Integration of an acceleration formula involving vectors

    Homework Statement Suppose a constant force F acts on a particle of mass m initially at rest. (a) Integrate the formula for acceleration \vec{a} = \frac{\vec F}{\gamma m} - \frac{\vec v}{\gamma mc^2}(\vec F \cdot \vec v) where \gamma = \frac{1}{\sqrt{1-\frac{v^2}{c^2}}} to show that the speed...
  35. V

    Adding & Subtracting Vectors: How to Determine the Final Vector Result

    Hello All, I'm taking a university physics course and while dealing with the introduction to vectors I believe I'm having more trouble at drawing diagrams than with the calculations (trigonometry) and therefore not having a clear diagram is causing some confusion. The problem is as follows...
  36. binbagsss

    Killing Vectors conserved quantity along geodesic proof

    I am trying to follow a proof that given a Kiling vector ##V^{u}##, the quantity ##V_{u}U^{u} ## is conserved along a geodesic. I am given the Killiing Equation: ## \bigtriangledown_{(v}U_{u)}=0 ## [1] Below ## U^{u} ## is tangent vector ## U^{u} = \frac{dx^{u}}{d\lambda} ## The proof...
  37. 7

    Determine if all vectors of form (a,0,0) are subspace of R3

    I have the feeling that it is, but I am not really sure how to start the proof. I know I have to prove both closure axioms; u,v ∈ W, u+v ∈ W and k∈ℝ and u∈W then ku ∈ W. Do I just pick a vector arbitrarily say a vector v = (x,y,z) and go from there?
  38. A

    Rotation matrix multiplied by matrix of column vectors?

    Hey, let's say that in 2D space we have a 2x2 rotation matrix R. Normally you could multiply this rotation matrix by a 2x1 column matrix / vector X. In that case it would be XR to get the vector rotated in the way described by R. Now what I'm wondering is, what if I had 3 column vectors that I...
  39. physicsquestion

    I need to figure this out: (A×B)⋅C

    Homework Statement Calculate (A×B)⋅C for the three vectors A with magnitude A = 5.00 and angle θA = 25.1∘ measured in the sense from the +x - axis toward the +y - axis, B with B = 4.18 and θB = 62.0∘, and C with magnitude C = 5.82 and in the +z - direction. Vectors A and B are in the xy-plane...
  40. J

    Vector Addition Problem - Statics

    Homework Statement Find the magnitude and direction of the resultant force Fr=F1+F2+F3 by first finding F'=F1+F2 then Fr=F'+F3 known values are in the link Homework Equations Basic vector addition. Law of cosines. Law of sines. The Attempt at a Solution Here's my attempt. I'm not convinced by...
  41. D

    Vectors in Tangent Space to a Manifold Independent of Coordinate Chart

    In Nakahara's book, "Geometry, Topology and Physics" he states that it is, by construction, clear from the definition of a vector as a differential operator [itex] X[\itex] acting on some function [itex]f:M\rightarrow\mathbb{R}[\itex] at a point [itex]p\in M[\itex] (where [itex]M[\itex] is an...
  42. I

    Choosing unit vectors for harmonic motion problems

    Consider a vertical pendulum affected by gravity (See the pdf file i included). Now i can choose two different opposite directions for my unit vectors which give me different equations. \downarrow : m\ddot x = mg-kx \uparrow : m\ddot x = kx-mg Which of course makes perfect sense, changing...
  43. Bassa

    The Line of Intersection of Two Planes

    Homework Statement Find a set of parametric equations for the line of intersection of the planes. 6x-3y+z=5 and -x+y+5z=5[/B]Homework Equations The cross product formula The formula for the parametric equations of a line in three dimensional space: x=x1+at, y=y1+bt, z=z1+ct Knowing the fact...
  44. M

    How Do You Determine Maximum Angular Separation in Vector Problems?

    So I was given this on a recent physics problem. http://prntscr.com/5s8u0u I understand vectors completely, I just don't know where to start. Specifically where it mentions maximum angular separation am I confused. Any type of hints/assistance is appreciated.
  45. binbagsss

    Vectors as a differential op and covectors as differenential

    Hey, I'm new to this , and I understand the derivation of the transition laws for overlapping regions of a manifold for covectors and vectors starting from thinking of them as a differential and a differential operator respectively, but I don't really have a clue where this comes from... Any...
  46. micromass

    Help with Vectors & Friction: Beginner's Guide (French)

    So this is a bit embarassing. But I enrolled in community college. I really can't wrap my head around vectors or friction. What books useful eh? I'm French btw
  47. Ganesh Ujwal

    MHB Proving Parallelism of Vectors with Perpendicularity Constraints

    I have to prove $\vec x \perp \vec z$ and $\vec y \perp \vec z$ imply $\vec x || \vec y$ where $\vec x,\vec y,\vec z \in \mathbb{R}^2$ and $z$ nonzero. I know $x \perp z \Leftrightarrow x_1z_1+x_2z_2=0$ and $y \perp z \Leftrightarrow y_1z_1+y_2z_2=0$. If two vectors are parallel, I can write...
  48. B

    MHB Vectors in $R^3$: Is $\begin{bmatrix}4\\3\\0\end{bmatrix}$ Valid?

    Is $\begin{bmatrix} 4 \\ 3 \\ 0 \end{bmatrix}$ in $R^3$?
  49. T

    About writing vectors in physics.

    I am confused as to how equations like F = mA would be solved. would you have to write the two Vector quantities in component form? And if not, how would a physicist turn the vector quantity in component form into a regular number for easy use?
  50. K

    Question based on using vectors

    Homework Statement Bjarne, Leif and Sammy are towing their vessel. The forces that they exert are directed along the tow lines, as indicated in Figure 15, which also provides the magnitudes of their forces. ( Note that in Figure 15, the force vectors are not drawn to scale.) What is the...
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