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. Physicsterian

    Extending an aircraft landing gear that has gotten stuck

    Imagine an aircraft of which the its wing is connected to its landing gear by means of a hinge (joint), and then the gear suddenly gets stuck midway. If, subsequently, the aircraft makes a turn around its longitudinal axis (see picture), it seems to hold true that then the angle between the...
  2. Physicsterian

    B Why does the force increase when holding a bag at an angle of 45 degrees?

    Hi, If 2 people are holding a bag at an angle of 45 degrees each, and then only person is going to hold it, it is being said that the force that will have to be applied by that one person will be 1.5 times greater than when he was applying it together with the other. Can anyone explain this or...
  3. M

    Dot product and basis vectors in a Euclidean Space

    Homework Statement I am asked to write an expression for the length of a vector V in terms of its dot product in an arbitrary system in Euclidean space. Homework EquationsThe Attempt at a Solution The dot product of a vector a with itself can be given by I a I2. Does that expression only apply...
  4. ubergewehr273

    Resolution of vectors for problems related to mechanics

    Homework Statement Refer the given image. [Prob 2.9] Homework Equations F=ma The Attempt at a Solution I drew the normal vector perpendicular to the surface of the cone and resolved it as ##Nsin\theta=mg## ##Ncos\theta=\frac {mv_{0}^2} {r}## where ##v_{0}## and ##r## are the speed and radius...
  5. R

    Balancing a shaft using mrL and mr vectors

    Homework Statement Homework Equations Trigonometry equations, p=m/v, A = pi * d^2 / 4 The Attempt at a Solution i) mass calculated is 9.318kg at 150° from A ii) diameter = 0.235m I apologize for the messy working, I am just wondering if I have followed the correct procedure or not...
  6. R

    B Addition of Perpendicular Vectors in two ways

    I have a Force Vector = 100N, making an Angle = 45 degrees with x-axis. When I find their Components trigonometrically, I get 70N each; as Fx = 100xCos(45) = 70N Fy = 100xSin(45) = 70N Verifying the result, by Head-to-Tail method, I get 70N + 70N = 140N. Why is there discrepancy or where am I...
  7. Pushoam

    Show: Vectors e.g.(a,b,1) do not form vector space.

    Homework Statement Homework Equations definition of null vector, [/B] The Attempt at a Solution null vector : ## |0 \rangle = (0,0,0) ## inverse of (a,b,c) = ( - a, -b, -c) vector sum of the two vectors of the same form e.g. (c,d,1) + ( e,f,1) = ( c+e, d+f, 2) does not have the same...
  8. Prez Cannady

    I Confused by this result for the tensor product of two vectors

    Given two probability distributions ##p \in R^{m}_{+}## and ##q \in R^{n}_{+}## (the "+" subscript simply indicates non-negative elements), this paper (page 4) writes down the tensor product as $$p \otimes q := \begin{pmatrix} p(1)q(1) \\ p(1)q(2) \\ \vdots \\ p(1)q(n) \\ \vdots \\...
  9. navneet9431

    What does the direction of angular velocity indicate?

    Angular velocity is the rate of angular displacement about an axis. Its direction is determined by right hand rule. According to right hand rule, if you hold the axis with your right hand and rotate the fingers in the direction of motion of the rotating body then thumb will point the direction...
  10. baldbrain

    Parallelism of Time-varying Vectors

    Homework Statement This is a solved problem, but I haven't understood a few things. I've marked out sections of the solution in white for convenience. The markings are positioned where that particular section ends. In part (1), how did they just assume f1(0) = 2, f2(0) = 3, g1(0) = 3, g2(0)...
  11. sams

    Representing Vectors in Newton's Notation: How to Use Overdot and Arrow Symbols?

    A very simple question. How do we represent a vector with Newton's notation (writing the arrow symbol with the overdot notation)? Can we write them both above each other. First, the overdot notation and then the arrow symbol? Thank you a lot for your help...
  12. I

    Why do position vectors have an arrow on top of them?

    According to the vector definition, the vectors have both the direction and magnitude such as displacement vectors which should possesses arrows on the top of them because they have displacement so they express a direction. On the other hand, position vectors are stationary, they do not have any...
  13. Onezimo Cardoso

    Orthogonal Vectors in Rn Problem

    Homework Statement Given ##a\neq b## vectors of ##\mathbb{R}^n##. Determine ##c## which lies in the line segment ##[a,b]=\{a+t(b-a) ; t \in [0,1]\}##, such that ##c \perp (b-a)##. Conclude that for all ##x \in [a,b]##, with ##x\neq c## it is true that ##|c|<|x|##. Homework Equations The first...
  14. Muhammad Danish

    What is the proper way to present mathematical problems on online forums?

    Homework Statement Homework Equations Is my solution correct? If not then please point out the mistakes and help me solve this question in the right way. Thanks in advance. The Attempt at a Solution
  15. Kaguro

    Understanding Polar Vectors on a Circle

    Homework Statement What is the sum of position vectors of all points on a circle? Don't use Cartesian system. Homework Equations Sum vector $$\vec s = \int_{\theta=0}^{\theta=2{\pi}}\int_{r=0}^{r=R} \, \,\vec P \, dr d\theta$$ where $$\vec P$$ is the position vector. The Attempt at a...
  16. M

    I Vectors & Frames Qs: Galilean & Lorentz Transforms

    Homework Statement Imagine there exists reference two frames, a frame O which is stationary and another, O' moving relative to O. If there is a four vector A--> (A0,A1,A2,A3). Then why is Aae->a as measured by the observer O equal to Aa'e->a' as measured by the observer O'? The components are...
  17. H

    Difference between two vectors

    Homework Statement In most problems involving projections I'm given a vector and the equation of a line either in parametric form or in symmetric form (ie. parametric: <0t+3, -t-4. 3t+2> or symmetric form: x=3, (y+4)/-1, (z-2)/3). However, when asked to use these in a problem I get confused...
  18. F

    MHB Choose from the following set of vectors in R4

    Hi everybody, I have a problem with this question: Choose from the following set of vectors in R4 set of the maximum number of linearly independent vectors: 1.(1;2;3;4) 2.(2;4;6;8) 3.(0;1;-1;1) 4.(1;1;1;0) 5.(0;3;0;0) So, I can find a rank of a matrix, it's 4, but I can't understand how it...
  19. S

    Algebra of Vectors: Find Difference & Multiply

    Homework Statement [/B] Homework Equations The Attempt at a Solution [/B] I am not sure if this is the correct way of finding the difference between two vectors. I thought that if "B" was negative then it's direction would change as well as it's angle. If the angle changes then are my...
  20. Sorcerer

    I Dyad as a product of two vectors: what does ii or jj mean?

    So I'm reading through some stuff trying to learn tensors, and I wanted to stop myself to grasp this concept before I go further. Along the way it was mentioned in one of the sources I'm looking at that other than the dot product and cross product, you could multiply vectors in another way, and...
  21. D

    I Killing vectors in isotropic space-times

    I've been reading up on Killing vectors, and have got on to the topics of homogeneous, isotropic and maximally symmetric space-times. I've read that for an isotropic spacetime, one can construct a set of Killing vector fields ##K^{(i)}##, such that, at some point ##p\in M## (where ##M## is the...
  22. M

    How Is the Derivative of Basis Vectors Computed in Polar Coordinates?

    Homework Statement I am unsure as to how the partial derivative of the basis vector e_r with respect to theta is (1/r)e_theta in polar coordinates Homework EquationsThe Attempt at a Solution differentiating gives me -sin(theta)e_x+cos(theta)e_y however I'm not sure how to get 1/r.
  23. G

    MHB How to Solve a Vector Word Problem Involving Airplanes and Wind?

    An airplane is flying on a bearing of South 27degrees West at 485 mph. A 35 mph wind is blowing from a direction of South 72degrees East. What is the actual bearing of the plane and the ground speed of the plane? I've been stuck on this problem for so long and am going to ask for help
  24. MathematicalPhysicist

    I Calculating Killing vectors of Schwarzschild metric

    I am trying to understand the solution to exercise 7.10(e) on pages 175-176 of Robert Scott's student's manual to Schutz's textbook. He writes the following: I don't understand how to find ##S^x, S^z## or ##T^x,T^z## from the metric or from the cartesian representation of the rotation...
  25. C

    Kinematics: A Complete Picture of Motion Without Causes

    So, if kinematics is the study of motion without reference to its causes (which is how it seems to be defined in many places), then here is my attempt to come up with a complete picture of motion without reference to its causes. This is just a summary to help me organize my thoughts (it is NOT...
  26. H

    Problem using vectors and relative motion

    Homework Statement A river of width 4 km flows at 5 km/h. A swimmer whose speed relative to water is 4 km/h, starts swimming from a point A on a bank. What minimum distance will the swimmer have to walk on the other bank to reach point B directly opposite to A? [/B]Homework Equations Vba = Vb...
  27. WhiteWolf98

    Vectors/ Calculus with i and j components

    Homework Statement I don't understand how to form an equation using the knowledge that, 'When ##t=4##, ##P## is moving parallel to the vector ##\mathbf {j}##'. I've seen the solution, and not a single part of it makes sense. I haven't attempted any question like this before, so I have no idea...
  28. J

    MHB Help Needed: Vectors - Calculate Plane Velocity & Direction

    Please can anyone help with: a plane has speed in still air (no wind) of 40kmh-1 and is traveling in a direction of 65 degrees bearing but there is a wind blowing at a speed of 20kmh-1 from the south east. If I is east and J is north, express the velocity p for the plane in no wind and velocity...
  29. H

    Find the angle between 2 vectors

    Homework Statement |a| = 2 |b| = ## \sqrt3## |a - 2b| = 2 Angle between a and bHomework EquationsThe Attempt at a Solution ##\theta## is angle between a and b So angle between a and -2b is 180-##\theta## [/B] ##|a-2b|^2## = |a|^2 + |2b|^2 -2|a||2b|cos(180-##\theta##) ##2^2## = 2^2 +...
  30. J

    I Which Vectors Can Legitimately be Broken into Components?

    I ran across the explanation below of a car on a banked turn (no friction) on a High School teacher's website. I'm assuming this is incorrect, because how can the normal force in this situation equal mg/cos when an object on an inclined plane has a normal force equal to mg * cos? The high...
  31. T

    MHB Find position vector using midpoint of two other vectors

    Hi, I've got this problem I'm trying to work out. The problem seems simple, but I don't think I have a good way to construct a way to solve it. This is the problem. Let P and Q be two points with position vectors p and q and let R be a point midway between these two. Find an expression for the...
  32. K

    I Basis Vectors & Inner Product: A No-Nonsense Introduction

    I read from this page https://properphysics.wordpress.com/2014/06/09/a-no-nonsense-introduction-to-special-relativity-part-6/ that the basis vectors are the canonical basis vectors in any coordinate system. This seems to be wrong, because if that was the case the metric would be the identity...
  33. K

    What does î(o) represent in vectors?

    This problem is fairly objective (though quite stupid) What does î(o) represent? Does it refer to a vector making angle 0 degrees with the x axis? I searched but couldn't find the answer anywhere. Please help. Moderator note: post edited and moved from hoemwork
  34. A

    I State Vectors vs. Wavefunctions

    Hi physicsforums, I am an undergrad currently taking an upper-division course in Quantum Mechanics and we have begun studying L^2 space, state vectors, bra-ket notation, and operators, etc. I have a few questions about the relationship between L^2, the space of square-integrable complex-valued...
  35. lc99

    Is there a trick to finding these 3D vectors in Cartesian coordinates?

    Homework Statement Homework EquationsThe Attempt at a Solution I am having a bit of trouble visualizing the vectors for these type of problems. The angles they give are very ambiguous and so I am not sure why they are there. For the 45 degree angle, how do i know that this is used for finding...
  36. Sandro Romualdez

    Vectors: Proving the value of a•(b x c)

    Homework Statement Given that vector a = (1, 2, -5), b = (-12, 41, 75) and c = a + 2b, explain why (without doing any calculations whatsoever) the value of a•(b x c) = 0 Homework Equations No specific equations, as the question asks for the value without making any calculations. This problem...
  37. Physics345

    Creating a question with vectors in 3-space (perpendicular)

    Homework Statement Describe how the dot product can be used to determine whether two vectors are perpendicular. Create a question with vectors in 3-space to illustrate this property. Solve the question as well. Homework EquationsThe Attempt at a Solution Did I do this right? I did something...
  38. Physics345

    Find the Coordinates/Magnitude of projection of two vectors

    Homework Statement Given two vectors u→=(16,5,2) and v→=(3,−2,−2) find the following: The coordinates of the projection of u→ on v→The magnitude of the projection of u→ on v→ . Homework EquationsThe Attempt at a Solution I have never done a question like this before, I was curious did I do...
  39. F

    B Representing Vectors: Calculating Force & Angle

    I recently had a test question where I had to calculate a force on a charged particles from two other charges particles. The answer ended up having an x and a y component. I realized I wasn’t quite sure how to represent that vector. Should I just have written it as something like 5Nx^ + 6Ny^...
  40. K

    How Do You Solve for t When Point E Lies on Line CD?

    Homework Statement A(-4,-4), B(4,-2) and D(-2,2) a) Determine AB and AD vector My answer: AB=[8,2] and AD=[2,6] b) A point C is determined by DC being parallel to AB and the angle ABC = 90. Calculate the coordinates of C. I found out that C=(46/17, 54/17) c) Another point E has the...
  41. F

    B Vector Math: Adding, Subtracting & Division

    As far as I know, vectors can only be added, subtracted, or “multiplied” by dot or cross product. Does this mean that you couldn’t divide f-> by a-> to get m using the vector form of Newton’s second law? This would require dividing a vector by a vector, which seems to not be allowed.
  42. F

    I Operators and vectors in infinite dimensional vector spaces

    Hello Everyone. I am searching for some clarity on this points. Thanks for your help: Based on Schrodinger wave mechanics formulation of quantum mechanics, the states of a system are represented by wavefunctions (normalizable or not) and operators (the observables) by instructions i.e...
  43. M

    Show that a set of vectors spans a subspace

    Homework Statement Show that {(1, 2, 3), (3, 4, 5), (4, 5, 6)} does not span R3. Show that it spans the subspace of R3 consisting of all vectors lying in the plane with the equation x - 2y + z = 0. Homework EquationsThe Attempt at a Solution I made a matrix of: A = [ 1 3 4 ; 2 4 5; 3 5 6] and...
  44. SirChris93

    How to find vectors and bisectors of an electric field

    <Moderator's note: User has been warned not to remove the template, and upload images instead of linking to an external site.> I'm very lost here, I don't know where to begin. My instructor is little help, the notes he gives are not even useful, and I cannot find anything in the book.We were...
  45. L

    Finding magnitude of vector without direction (kite problem)

    Homework Statement A child is flying a large kite of mass 6.8 kg on a windy day. At the moment shown the tension from the string on the kite has a magnitude of 17.0 N and makes an angle of = 32.6° from the vertical, and the acceleration of the kite has a magnitude of ak = 7.72 m/s2 and makes...
  46. V

    Minimum and maximum resultant of three vectors.

    Homework Statement In order to solve a question, I need to find the minimum and maximum resultant of three vectors, their magnitudes are given to me. Homework Equations Magnitude of vector A = 1 Magnitude of vector B = 3 Magnitude of vector A = 5 The Attempt at a Solution The maximum part was...
  47. Phantoful

    How do I solve for the angle, as a function?

    Homework Statement Homework Equations [/B] The two equations in the image, as well as (maybe) standard vector operations like dot product, cross product. The Attempt at a Solution [/B] So, I've tried to do what my instructor suggested and put everything in terms of Earth (Using RE and TE...
  48. J

    Linearly Independent Eigen Vectors

    Solved (sorry i tried again and realized my E-values were wrong) 1. Homework Statement Homework Equations Find Eigen Values and then what? The Attempt at a Solution I got eigen values as 3 and -3. Now how to proceed? I got Eigen Vector as: 1, 1 for eigen value of 3 and eigen vector as 8, 2...
  49. Meeeessttteeehh

    Verification for Net Force and Vectors?

    Hello everyone! I was given the following three questions in my homework, and I had a lot of trouble with them, so I was hoping someone could look them over! If you could just check out my pictures and say "yeah its awesome!" or "nope... [insert helpful answer here]" that would be GREAT. Thanks...
  50. Richie Smash

    Find the speed of the batsman and direction he takes (vectors)

    Homework Statement Hello, I havre problem here relevant to an image I will attach. ''A cricket ball hit by a batsman moves with a speed of 6m/s along a straight line path PQRS, as shown in the diagram. When the ball is at R, a fieldsman starts to run in a straight line from T with a speed of...
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