What is Vectors: Definition and 1000 Discussions

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. C

    I need some clarification for a high school vectors question (accelerating bird)

    Homework Statement A bird flying in the air accelerates 2.82 m/s2 north for 4.11 seconds. the final velocity of the bird is 9.09 m/s [east]. What was the initial velocity of the bird? Homework Equations vf=v0+a*t v(average)=(v0+vf)/2 v=d/t d=v0t +½at2 tanθ=opp/adj The Attempt at a Solution...
  2. P

    I Confusion about index notation and operations of GR

    Hello, I am an undergrad currently trying to understand General Relativity. I am reading Sean Carroll's Spacetime and Geometry and I understand the physics (to a certain degree) but I am having trouble understanding the notation used as well as the ideas for tensors, dual vectors and the...
  3. T

    MHB Are the Vectors S and T in the column of (ABC)

    I have no clue how to decode this question or do it but I was given the vectors S=[1 1 0] and T=[-1 0 1] and asked to determine whether or not they are in the column space of ABC when A, B and C are 3x3 matrices. My prof hinted to "think of rank and nullity", can someone please point me in the...
  4. P

    How Do Dot Products Reflect Vector Projections?

    I know that a dot product of 2, 2 dimension vectors a, b = (ax * bx) + (ay * by) but it also is equal to a*bCos(θ) because of "projections". That we are multiplying a vector by the 'scalar' property of the other vector which confuses me because that projection is in the direction of the...
  5. Boltzman Oscillation

    I Vector math (small angle approximation)

    Given the following vectors: how can i determine that Θ = Δp/p ? I can understand that p + Δp = p' but nothing arrives from this. Any help is welcome!
  6. JuanC97

    I Is my reasoning about commutators of vectors right?

    Hello guys, I have a question regarding commutators of vector fields and its pushforwards. Let me define a clockwise rotation in the plane \,\phi:\mathbb{R}^2\rightarrow\mathbb{R}^2 \,.\; [\,\partial_x\,,\,\partial_y\,]=0 \,, \;(\phi_{*}\partial_x) = \partial_r and \,(\phi_{*}\partial_y) =...
  7. bardia sepehrnia

    Calculating a force on a member (Statics)

    I isolated the member ABC and drew the free body diagram: α is then calculated using inverse tan: Tan-1=(6.25+15)/50=23.03 Then force of member BD on the joint can be found by sum of all moments around point A. Then Ax is calculated which is equal to BD×Cos(α)=235.2×Cos(23.03) Ax=216.48...
  8. wafelosek

    A Killing vectors corresponding to the Lorentz transformations

    Hi everyone! I have a problem with one thing. Let's consider the Lorentz group and the vicinity of the unit matrix. For each ##\hat{L}## from such vicinity one can prove that there exists only one matrix ##\hat{\epsilon}## such that ##\hat{L}=exp[\hat{\epsilon}]##. If we take ##\epsilon^{μν}##...
  9. hnnhcmmngs

    But, as I said, you don't actually need the coordinates at all.

    Homework Statement Calculate |u+v+w|, knowing that u, v, and w are vectors in space such that |u|=√2, |v|=√3, u is perpendicular to v, w=u×v. Homework Equations |w|=|u×v|=|u|*|v|*sinΘ The Attempt at a Solution [/B] Θ=90° |w|=(√2)*(√3)*sin(90°)=√(6) Then I tried to use u={√2,0,0}...
  10. hnnhcmmngs

    Vectors and scalar projections

    Homework Statement Let a and b be non-zero vectors in space. Determine comp a (a × b). Homework Equations comp a (b) = (a ⋅ b)/|a| The Attempt at a Solution [/B] comp a (a × b) = a ⋅ (a × b)/|a| = (a × a) ⋅b/|a| = 0 ⋅ b/|a| = 0 Is this the answer? Or is there more to it?
  11. karush

    MHB Set of vectors form a vector space

    this is what is given so by addition $$\begin{bmatrix}x_1\\y_1\\5z_1\end{bmatrix} \oplus \begin{bmatrix} x_2\\y_2\\5z_2 \end{bmatrix} = \begin{bmatrix} x_1+x_2\\y_1+y_2\\5z_1+5z_2 \end{bmatrix} = \begin{bmatrix} X\\Y\\10Z \end{bmatrix}$$ uhmmmm really?
  12. Charge

    Adding Vectors to Find Velocity

    Problem: Dr. L and his cat Kepler are coming home from fishing. They ended their trip on the south bank of a river, directly across a 1200 m wide river, from where Caroline was going to pick them up on the north bank. They are in identical boats that can travel at 4 m/s (Vb). The river is...
  13. F

    I Polar coordinates and unit vectors

    Hello, I get that both polar unit vectors, ##\hat{r}## and ##\hat{\theta}##, are unit vectors whose directions varies from point to point in the plane. In polar coordinates, the location of an arbitrary point ##P## on the plane is solely given in terms of one of the unit vector, the vector...
  14. Mason Smith

    Cylindrical coordinates: unit vectors and time derivatives

    Homework Statement Homework EquationsThe Attempt at a Solution I have found expressions for the unit vectors for cylindrical coordinates in terms of unit vectors in rectangular coordinates. I have also found the time derivatives of the unit vectors in cylindrical coordinates. However, I am...
  15. ashhlyn

    Finding the expression for the x-component of velocity (vectors?)

    Homework Statement a particle's position is the vector r=(ct^2-2dt^3)i+(4ct^2-dt^3)j where c and d are positive constants. find the expression for the x-component of the velocity (for time t>0) when the particle is moving in the x-direction. you should express your answer in terms of variables...
  16. CrosisBH

    Finding an area of a triangle formed by three points

    Homework Statement P(3, 0, 3), Q(−2, 1, 5), R(6, 2, 7) (a) Find a nonzero vector orthogonal to the plane through the points P, Q, and R. (b) Find the area of the triangle PQR Homework Equations A = \frac{1}{2}|\vec{AB}\times\vec{AC}| Source...
  17. K

    Can somone help me with vectors?

    Homework Statement A tent with no bottom stands in a terrain. The tent has three rods that are gathered in T = (1,1,4). The tent bars stands in the points A = (0,0,0), B = (3,1,1) and C = (- 1,3,2). The tent must be supported by an additional rod which is in a point D and attached to T. The rod...
  18. George Keeling

    I Why are scalars and dual vectors 0- and 1-forms?

    I am told: "A differential p-form is a completely antisymmetric (0,p) tensor. Thus scalars are automatically 0-forms and dual vectors (one downstairs index) are one-forms." Since an antisymmetric tensor is one where if one swaps any pair of indices the value of the component changes sign and 1)...
  19. Prez Cannady

    I Representing nonlinear functions involving vectors

    I'm having trouble finding textbook material on nonlinear functions on vectors. Just as I could define a function ##f## such that: $$f(x) = cos(x)$$ I'd like to write something like: $$f(\vec{x}) = \begin{pmatrix} f_1(x_1) \\ f_2(x_2) \\ ... \\ f_n(x_n) \end{pmatrix} $$ where ##f_i## is...
  20. Specter

    Why does the cross product of two direction vectors....

    Homework Statement [/B] Hopefully this is in the correct section I looked around for others but this seemed like the right one. Find the scalar, vector, and parametric equations of the plane that passes through the points P(1,0,4), Q(3,1,-6), and R(-2,3,5). Homework EquationsThe Attempt at a...
  21. E

    MHB Find the angle between 2 vectors w=i+3j, vector v=<5, 2>

    I know how to find the cos(theta) between two vectors but I do not know how to find the sin(theta). vector w=i+3j vector v=<5, 2>
  22. B

    MHB Left or Right Angles ( + or - ) of adjoining vectors

    Hi there, I have another one for you (Blush) How can I efficiently determine if the angle between 2 vectors is positive or negative... Take a look at this example drawing: Known are the xy coordinates of 2 adjoining vectors, (I also have calcullated the 360 deg angle relative to the x-axis...
  23. E

    MHB Find the sin angle between two 2d vectors

    Tomorrow is my math test and I'm going over the study guide: I have vector U=<1, 3> and vector V=<5, 2> It says let theta be the missing angle between the two vectors. What is the cos(theta) and sin(theta)? I already know how to find the missing angle for cos(theta) but we never covered how...
  24. astroman707

    Courses Is it okay to not understand the calculus in intro physics?

    I don't understand a good portion of the non-algebraic math behind much of the physics in my first semester college class. I understand everything with algebra, and can solve all problems, but I don't understand the relationships with vector cross/dot products, calculus derivations, DE, etc...
  25. Math Amateur

    MHB Tangent Vectors in R^n as Derivations ....

    I am reading Loring W.Tu's book: "An Introduction to Manifolds" (Second Edition) ... I need help in order to fully understand Tu's section on tangent vectors in \mathbb{R}^n as derivations... In his section on tangent vectors in \mathbb{R}^n as derivations, Tu writes the following: In the above...
  26. F

    Maximizing Vector Sum with Constant Magnitudes

    <Moderator's note: Moved from a technical forum and thus no template.> Let there be two vectors, u and v. Whose magnitudes are constant u = [a, b] v = [x, y] Define c = ||u|| and k = ||v|| Now sum the vectors: w = u + v = [a, b] +[x, y] = [a+x, b+y] Now find ||w|| ||w|| =√(a+x)2+(b+y)2...
  27. A

    What do surface tension vectors mean in this quote?

    I was reading Fundamentals of Inket Printing and it said the following: "The surface tension in a liquid causes a force to act in the plane of the free surface perpendicularly to a free edge in that surface." Can someone explain to me what this means? What's the direction of the force? I have...
  28. M

    MHB Vectors in a coordinate system

    Hey! :o We have the basis $B=\left \{\begin{pmatrix}1 \\ 1 \\ 1\end{pmatrix},\begin{pmatrix}2 \\ 1 \\ 0\end{pmatrix}, \begin{pmatrix}1 \\ 2 \\ 1\end{pmatrix} \right \}$ of $\mathbb{R}^3$ and the vector $v$ can we written as a linear combination of the elements of the basis as follows...
  29. PainterGuy

    The components of force and velocity vectors in circular motion

    Hi! I was trying to understand circular motion and came across two problems. I would really appreciate if you could help me with those. Question 1: In the picture below let's assume that the angle θ is 1 radian, i.e. 57.3°, radius is 1 m. It would mean that the length of arc AB is also 1 m...
  30. G

    Confusion about the direction of the vectors: motional EMF

    Homework Statement I'm working through an example with motional EMF and I'm having trouble understanding the directions of vectors so that I can apply induction law. The magnetic circuit seems complex because the circuit is used to analyze other situations but the air gap 3, the coil 3 and the...
  31. D

    I Transforming Contra & Covariant Vectors

    Hi. The book I am using gives the following equations for the the Lorentz transformations of contravariant and covariant vectors x/μ = Λμν xν ( 1 ) xμ/ = Λμν xv ( 2 ) where the 2 Lorentz transformation matrices are the inverses of each other. I am trying to get equation 2...
  32. M

    X and Y components of velocity and acceleration vectors

    Homework Statement (Translating from a Polish high school textbook, so if anything is unclear please let me know). An object moves on a trajectory described by the parabola ##y=\frac{1}{2\lambda}x^2## such that the ##x## component of its velocity is constant and equal to ##v_0##. The...
  33. M

    Vectors: How to prove the BAC-CAB identity w/o components?

    Homework Statement Prove that $$\bf{ a \times ( b \times c ) = \phi [ b(a \bullet c) - c(a \bullet b) ]} $$ for some constant phi Homework EquationsThe Attempt at a Solution So I have used the unit vectors i, j, and k and found out that phi = 1. With the main part of the proof, we are not...
  34. Zeynel

    B The definition of “vector” in math and physics

    I'm learning APL and this is how a vector is defined https://tryapl.org: All data resides in arrays. An array is a rectangular collection of numbers, characters and arrays, arranged along zero or more axes. We can use more specific terms for some arrays, like a single number is a scalar, a list...
  35. DuckAmuck

    I Can any matrix be expressed as the product of two vectors?

    For example, does this always hold true? M_ab = v_a × w_b If not, where does it break down?
  36. M

    Prove that the standard basis vectors span R^2

    Homework Statement I know how to approach this problem; however, I'm just confused as to why we consider that R^2 is a vector space over the field R, and not Q or any other field for this question? Standard basis vectors: e_1, e_2 or i,j
  37. S

    How much time for this person to drive across time zones? (vectors)

    Homework Statement A man drives a car starting 5.00 km due West from the line marking the Eastern time zone. He travels at 30 m/s along a straight road that runs in a direction E 30° N. How much time does it take the man to get to the Eastern time zone? (The man must travel along the road: no...
  38. E

    Vectors and Two Dimensional Motion

    Homework Statement The velocity of an airplane is 425 km/h, in a direction of 40 degrees north of east. The wind is blowing at a velocity of 75 km/h northward. A. What is the resultant velocity of the plane? B. How long does it take for the plane to make a displacement of 2000 km? Homework...
  39. T

    Number of indie vectors ##\leq ## cardinality of spanning set

    Homework Statement In a finite-dimensional vector space, the length of every linearly independent list of vectors is less than or equal to the length of every spanning list. It's quite long :nb), hope you guys read through it. Thanks! :smile: Homework Equations N/A The Attempt at a Solution...
  40. olgerm

    I How are basis vectors defined?

    hi. if I know how to convert coordinates from a system to cartesian system, then how can I find basevectors of that coordinatesystem? Is it possible that basevectors are different in different points(with different coordinates)? What is most general definition of basevectors? I tought it would...
  41. J

    Find Vector Representation of |ψi> in |ei> basis

    Homework Statement Consider the following ket: |ψi> = c1|e1> + c2|e2>, where ci are some complex coefficients. Find the column-vector representation of |ψi> in the |ei> basis. Find the row-vector representation of <ψ| in the <ei| basis. Homework Equations |ψi> = c1|e1> + c2|e2> The Attempt at...
  42. TytoAlba95

    How are pUC vectors designed for efficient sequencing of insert DNA?

    'The MCSs of many vectors such as the pUC series are flanked by sequences complementary to a universal series of primers, the M13 forward and reverse primers. These priming sites are oriented such that extension of the primers annealed to these sites allows sequencing of both ends of an insert...
  43. P

    How do you find the acceleration needed to clear a jump?

    Homework Statement Homework Equations The Attempt at a Solution I used Pythagorean theorem to find the length of the ramp (25^2+18^2 = √949) and found the angle of elevation using tangent (Tanθ=18/25) but then got stuck on what formula to use.
  44. sams

    I A Question about Unit Vectors of Cylindrical Coordinates

    I wrote the equations of the Nabla, the divergence, the curl, and the Laplacian operators in cylindrical coordinates ##(ρ,φ,z)##. I was wondering how to define the direction of the unit vector ##\hat{φ}##. Can we obtain ##\hat{φ}## by evaluating the cross-product of ##\hat{ρ}## and ##\hat{z}##...
  45. alexi_b

    Map question involving vectors (find the angle)

    Homework Statement Instructions for finding a buried treasure include the following: Go 66.0 paces at 256deg, turn to 140deg and walk 125 paces, then travel 100 paces at 169deg. The angles are measured counterclockwise from an axis pointing to the east, the +x direction. Determine the resultant...
  46. alexi_b

    Vector Addition Question: find angle (A+B & A-B)

    Homework Statement Two vectors A and B have precisely equal magnitudes. For the magnitude of A + B to be 65 times greater than the magnitude of A - B, what must be the angle between them? Homework EquationsThe Attempt at a Solution I tried using the dot product and solving for the angle but i...
  47. B

    B Direction of Vectors: North vs Northeast

    What's the difference between saying that a vector's direction is north of east and north east?
  48. Pouyan

    Finding state vectors for pure states

    Homework Statement Is the following matrix a state operator ? and if it is a state operator is it a pure state ? and if it is so then find the state vectors for the pure state. If you don't see image here is the matrix which is 2X2 in MATLAB code: [9/25 12/25; 12/25 16/25] Homework...
  49. S

    Orthogonal projection onto a plane spanned by two vectors

    Homework Statement x = <0, 10, 0> v1 = <4, 3, 0> v2 = <0, 0, 1> Project x onto plane spanned by v1 and v2 Homework Equations Projection equation The Attempt at a Solution I took the cross product k = v1xv2 = <3, -4, 0> I projected x onto v1xv2 [(x*k)/(k*k)]*k = <-4.8, 6.4, 0 = p I finished...
  50. Physicsterian

    Defining which cyclist profits the most from slipstream

    Homework Statement - Question: Which cyclist (A, B or C) profits the most from cyclist slipstream (also called “aerodynamic drafting”)? - Given: the direction of the wind, the positions of each cyclist; an illustration representing this - NOTE that I am expected to solve this question...
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