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. C

    Kinematics question -- Adding and subtracting vectors

    Homework Statement If vector a is added to vector b, the result is the vector c = (7.00, 3.00). If b is subtracted from a, the result is the vector d = (−4.50, 9.25). what is the magnitude of a? what is the magnitude of b? Homework EquationsThe Attempt at a Solution a + b = (7.00, 3.00)c...
  2. M

    Calculating Tension in a Horizontal Clothesline with Vectors

    For some reason I'm really struggling to get a correct answer on this problem "A horizontal clothesline is tied between 2 poles, 20 meters apart. When a mass of 3 kilograms is tied to the middle of the clothesline, it sags a distance of 4 meters. What is the magnitude of the tension on the...
  3. S

    How do you graph vectors on a graph paper using their magnitude and direction?

    Homework Statement Vector A: 1.96N at 20° Vector B: 1.71N at 65° Homework EquationsThe Attempt at a Solution I change the Newtons to cm. Vector A: 1.96cm and Vector B: 1.71cm. I multiplied it by 2 so it would look bigger on the graph paper. Vector A: 3.92cm and Vector B:3.42cm. I was able to...
  4. S

    How do I find Vector C in a non-right triangle using the Law of Cosines?

    Homework Statement Vector A: 1.96N at 20° Vector B: 1.71N at 65° There are different parts I did the graph part by hand. I am having trouble finding it analytically. We have to use cm for our triangle. Homework EquationsThe Attempt at a Solution Vector A: 1.96 cm at 20° Vector B: 1.71 cm at...
  5. W

    Methods in Calculating with Vector Components

    <Moderator's note: Moved from a technical forum and therefore no template.> Homework Statement A proton (q = 1.60 x 10-19) is in a uniform, 0.500 T magnetic field. This proton has velocity components vx = 1.50 x 105, vy = 0, and vz = 2.00 x 105 m/s. Find the force on the proton at t=0. 2...
  6. Epoch

    Calculating Reaction Forces on Cylinders Resting on an L Profile

    Homework Statement Two cylinders, each with a mass of 10kg, are lying on an L profile. Neglect the thickness and weight of the L profile. Calculate the reaction force in b and e. Homework Equations G = mg The Attempt at a Solution So I tried to make a free body diagram of the cylinders. I...
  7. E

    Vector Addition and Subtraction for Homework Help

    Homework Statement [/B] For the vectors A and B (shown in the figure attached), carefully sketch: - The vector sum C = A + B - The vector difference D = A - B - The vector E = -A - B - The vector difference F = B - A Homework Equations Please explain how to do this. The Attempt at a...
  8. F

    Exploring Vector Addition for Beginners

    Homework Statement [/B] Sketch in a third vector, C, whose magnitude and direction are such that A+B+C=0. Vectors A and B both have a magnitude of 5 and form a 30 degree angle (image attached).Homework Equations [/B] How do I go about this question? I have no idea how to start or what to...
  9. S

    I Difference between vectors and one-forms

    Hello! I am reading some introductory differential geometry and they define the vector space associated to a point of a manifold as the tangent plane at that point. Intuitively it makes sense to call these vectors (just as the speed is the tangent to the trajectory), but why are those called...
  10. C

    MHB Physics-Using vectors to find the components

    Hello Everybody, A trapper walks a 6.2 km straight-line distance from the cabin to the lake, beginning to the lake has an angle of +45 degrees. Determine the east and north components of her dispacement vector. Work: E component: $6.2\times\cos\left({45^{\circ}}\right)$ = 4.38 N...
  11. E

    Solving Vector Problems: Step-by-Step Guide

    Homework Statement :[/B] Draw the vectors: A.) 60 lbs at 25 degrees east of north. B.) 40 lbs at π/3 south of west. Homework Equations [/B] I've tried different things but keep getting the wrong answer. Can someone please explain how to solve these types of problems?The Attempt at a Solution...
  12. Y

    Two masses coalesce into one body during collision

    Homework Statement Question: A body of mass M1=m moving with a velocity V1=v in the x-direction collides with another body of the same mass m2=m moving in the y-direction with the same speed V2=v The coalesce into one body during collision Homework Equations (a) Find the magnitude of the...
  13. L

    Vector dot product and parallel vectors

    Homework Statement show that points P, Q and R are in a straight line P (1, -3, 4) Q ( 2, 2, 1) R (3, 7, -2) and find the vectors ## \vec{PQ} ## and ## \vec{QR} ## Homework EquationsThe Attempt at a SolutionIn proving that the points are in a straight line, we might be able to use dot product...
  14. A

    Find the ratio of two line segments in a triangle

    1. The problem statement, all variables, and given/known data Triangle ABC has a point D on the line segment AB which cuts the segment in ratio AD : DB = 2 : 1. Another point E is on the line segment BC, cutting it in ratio BE : EC = 1 : 4. Point F is the intersection of the line segments AE and...
  15. R

    Weird question in "Vectors" chapter

    Homework Statement Two aircraft approaching an aircraft carrier are detected by radar. The first aircraft is at a horizontal distance of 34.3 km in the direction 42 deg north of east. and has altitude 2.4 km The second aircraft, at altitude 1.2 km, is at horizontal distance of 42.6 km in the...
  16. karush

    MHB T12.3.11 Find the angle between vectors

    ok don't know the book answer but think this is ok suggestions welcome:cool: $\tiny{t12.3.11}\\$ $\textsf{Find the angle between vectors}$ \begin{align*}\displaystyle u&=\sqrt{3i}-7j\\ v&=\sqrt{3i}+j-2k\\ u \cdot v&=(\sqrt{3})(\sqrt{3}) + (-7)(1)+(0)(-2)\\ &=3-7+0\\ &=-4 \end{align*}...
  17. A

    Darryl drives his load of tomatoes.... (Velocity vectors pic)

    Homework Statement Homework Equations a^2+b^2=c^2 c^2=a^2+b^2-2abCos(theta)The Attempt at a Solution I'm having trouble trying to draw out the vectors. This is my attempt. I feel like it is wrong. Can someone help out please? Also, I'm not sure where to go from here... If I used...
  18. karush

    MHB Hcc8.12 Find the sum of vectors

    $\tiny{hcc8.12}$ $\textsf{Find the sum of vectors $(10, \, 45^o)$ and $(7, \, 150^o)$}\\$$\begin{align*}\displaystyle \textsf{magnitude} &=\sqrt{(10\cos45^o - 7\cos150^o)^2 + (10\sin45^o - 7\sin150^o)^2} \approx 12.114 \end{align*}$ ok an online vector sum calculator returned 10.619 so...
  19. F

    I Timelike Killing vectors & defining a vacuum state

    I've read that if a given spacetime possesses a timelike Killing vector, then it is possible to define a unique vacuum state by constructing positive and negative frequency modes with respect to this timelike Killing vector. My question is, what does this mean? Explicitly, how does one use a...
  20. Philosophaie

    A Calculating Compound Angle b/w Planet & Earth-Sun Vectors

    A certain planet has a vector (Recl, L, B). The Earth and Sun vector exists on ecliptic. I need to know how to calculate the compound angle between the planet vector and the Earth-Sun vector.
  21. L

    MHB Find XYZ for Tip of Vector Given Info on 2 Other Vectors w/ Tails at Same Point

    I have posted this in University linear algebra, but it is possible there is a simple answer for this and the the problem belongs in some other forum. I apologize if that is the case. I am starting with 3 points in 3 space, along with the centroid of the full data set. The data is in principle...
  22. Pushoam

    Kinematics 5 -- Vectors to two particles that are going to collide....

    Homework Statement Homework EquationsThe Attempt at a Solution The two particles are supposed to move along the same line. And the two radius vector could be anything. Is this correct?
  23. chopnhack

    Understanding the Direction of Electric Field Vectors

    I saw this thread "https://www.physicsforums.com/threads/electric-fields-magnitude-and-direction.765309/" If i understand this concept better now: E1 is facing opposite its source at +3 nC because it is a positive charge and the field flows out from the charge whereas -5 nC's vector points...
  24. B

    Help (: adding vectors components.... angles, drawing.

    Homework Statement A ship traveling 55 degrees [W of N] is 65km farther north after 3.0h. What is the ship's velocity. Homework Equations sin, cos, tan? The Attempt at a Solution I know that Vground= Vair + Vwind, and that Vground = Vboat + Vcurrent, but I'm not sure if that is even relevant...
  25. davidge

    I Finding Killing Vectors for $$ds^2 = dr^2 + r^2d\theta^2$$

    I have tried to find the three Killing vectors for the metric $$ds^2 = dr^2 + r^2d \theta^2$$ that is, the Euclidean metric of ##\mathbb{R}^2## written in polar coordinates. I found these to be $$\bigg(\text{first}\bigg) \ \ \xi_r = \text{Cos} \theta \\ \xi_\theta = -\text{rSin} \theta \\...
  26. Z

    Dot Product of Streaming vectors

    Hi all, Suppose we have vectors coming in order as A, B and then C (but A must be deleted before C comes in). Then how to get the dot product between A and C? It is allowed to store some calculations of A before deleting elements of A, for example, we could store norm of A, dot(A, B) and etc...
  27. Jamison Lahman

    What is the correct angle between two vectors?

    Homework Statement From Analytical Mechanics by Grant R. Fowles & George L. Cassiday. Only problem I am having is with part d. Homework Equations ##A\cdot B = A_xB_x+A_yB_y+A_zB_z## ##sin(\theta) = \frac{|A\times B|}{AB}## The Attempt at a Solution I did it by hand but also ran the following...
  28. donaldparida

    Find the angle between this vector and the coordinate axes

    Homework Statement : [/B] r vector = 3t i + (4t-5t2)j. Find the angle made by the vector with respect to the x-axis and the y-axis. 2. Homework Equations : A.B=AxBx+AyBy 3. The Attempt at a Solution : I tried to take the dot product of the unit vector along x-axis and r. I did the same...
  29. aatari

    Vector Addition: Components with Given Directions and Magnitudes

    Homework Statement Hi, can you guys please see if my solution is correct. Any feedback would be awesome. Using components determine the sum of a + b if a = 3 m [N 30° W] and b = 2 m [N 10° E]. Homework Equations N/A The Attempt at a Solution
  30. aatari

    Adding Vectors: Understanding Direction and Length

    Homework Statement Hi Guys, I am a bit unclear regarding adding vectors and hoping someone can clear up the confusion for me. In the image below, we are adding two vectors and we used the vector components to find find x and y. Finally we then used x and y to get the resultant and the angle...
  31. C

    MHB What is the method for solving vector problems with component form and addition?

    Hi everyone, I am taking my finals next week and I am really excited. But I forgot how to solve problems like these I know I'm supposed to separate them and solve for x and y seperately but its still not ringing any bells. Vector L is 303m long in a 205* direction. Vector M is 5552 m long in a...
  32. Adhil

    MHB Finding Coordinates of Point B - Positional Vectors

    I need help finding the coordinates of point B. I have the answer from the textbook but I have no clue how they got it. I also cannot go any further until I solve it. Note: I am studying at home so I have no lectures to go to for help. Questions is 3.4...
  33. N

    Calculating tensions in ropes suspending an onject

    Homework Statement A mass of 20 kg is suspended from a ceiling by two lengths of rope that make angles of 30° and 45° with the ceiling . Determine the tension in each of the strings. 2.Relevant equations Fg= mg The Attempt at a Solution Fg= 20 x 9.8 = 196 N ∑F= fnet=ma Fg-FTtotal= 0 196=...
  34. W

    Basics of Vectors -- Parallel versus Co-Planar

    Homework Statement Ex. 2. Express each of the following by an equation: (a) Two vectors A and B are parallel. (b) Three vectors A, B and C are co-planar. Homework Equations C = A + B 3. The Attempt at a Solution I understand (a) the answer being B = (alpha)*A because that is a scalar...
  35. Diksha17

    I Vector Parity: +1 or -1? Scalar Difference Explained

    Why is a vector's parity +1 and pseudo vector's parity -1 ? While it is the opposite case for scalars.
  36. L

    MHB Vectors in Planes: Solving for m & n, Finding Orthogonal Plane

    Hiya, I have a question in high school math, vectors to be precise: The point K(3.5,-0.5,-2) is the intersection point of the plane S1: mx-7my+5z+3=0 with the line l1: (n,1,-2)+t(-1,1,0) a) find the parameters n and m b) find the equation of the plane that contains the line l1 and is...
  37. donaldparida

    Finding the resultant of three vectors

    Homework Statement : [/B]Determine the resultant of three vectors of magnitude 1, 2 and 3 whose directions are those of sides of an equilateral triangle taken in order.Homework Equations : [/B] R2 = A2 + B2 + 2 A B cos θ tan α = B sin θ/(A+B cos θ) The Attempt at a Solution :[/B]...
  38. Bunny-chan

    Distance between point coordinates in a straight line

    Homework Statement Let A = (1,2,5) and B = (0,1,0). Determine a point P of the line AB such that ||\vec{PB}|| = 3||\vec{PA}||. Homework EquationsThe Attempt at a Solution Initially, writing the line in parametric form\vec{AB} = B - A = (0-1,1-2,0-5) = (-1,-1,-5)\\ \\ \Rightarrow \vec{v} =...
  39. P

    Solving Car Collision: Velocity Impact of 40cm Rear End Impact

    Hi all, I am currently self teaching physics and have come across something i don't know how to do. There are 2 cars, Cars 1 and 2, traveling at a velocity of 60km/h (16.67m/s) in the eastern direction with a gap of 5 metres between each other. Car 2 is in front of Car 1. Car 2 decelerates to...
  40. N

    MATLAB Why 2 vectors are not the same in matlab?

    I have 2 vectors: a = 1.0e-04*[0.110000000000000 0.140000000000000 0.140000000000000 0.140000000000000]; b = [0.000011000000000 0.000014000000000 0.000014000000000 0.000014000000000]; by look at by eyes, it seems similar; but when I use this command: a == b then I got...
  41. Mr Davis 97

    I Distinction between coordinates and vectors

    I am a little confused about the difference between between coordinates and vectors. For example, when first studying vector calculus, you learn about vector fields, which formally are maps ##f: \mathbb{R}^n \to \mathbb{R}^n##, and we say that the function associates to every point in space a...
  42. Bunny-chan

    Understanding a book example about centripetal force

    Homework Statement If the centripetal force is at the left side of the equation; that means if we move it over to the other side, it'll have a negative sign, which means it is opposite in sense in relation to N and mg. But how is that possible, considering that the centripetal force always...
  43. Arman777

    I Whats the meaning of Parallel in Vectors

    Lets suppose we have a two vectors where ##\vec u=c\vec r## where c is just a reel constant number.Can we say ##\vec u## and ##\vec r## is parallel. How can we define ""parallel" vectors ? Like in most general way. I know that when c is positive real number they are definately...
  44. Bunny-chan

    Dynamics problem about two-dimensional tug-of-war

    Homework Statement In a two-dimensional tug-of-war, Alex, Betty, and Charles pull horizontally on an automobile tire at the angles shown in the picture. The tire remains stationary in spite of the three pulls. Alex pulls with force \vec{F_A} of magnitude 220~N, and Charles pulls with force...
  45. Vitani11

    Representation of vectors in a new basis using Dirac notation?

    Homework Statement I have a vector V with components v1, v2in some basis and I want to switch to a new (orthonormal) basis a,b whose components in the old basis are given. I want to find the representation of vector V in the new orthonormal basis i.e. find the components va,vb such that |v⟩ =...
  46. H

    I What is the purpose of cross multiplication in vector multiplication?

    Hi, what does it mean to cross multiply two vectors? I couldn't imagine them in real life. eg Force vector. Multiplying Force vector to a scalar value means you multiple the 'Strength' of the force, Dot multiplication of Force with displacement to get work, means you get the work in...
  47. Deadawake

    Calculate Change in Speed Using Unit Vectors: Easy Physics Solution

    Actually that's very easy question but I have some difficult to understand the logic behind . So-"The initial velocity of an object (m/s) is Vi=1i+5j+2k. And the final velocity is Vf=3i+5j+7k. What was the change in speed of the object?"X Solution - |Vf|-|Vi| = √(32+52+72)-√(12+52+22) = 3.63...
  48. A

    Find the equation of the plane given point and line (3D)

    ∴1. Homework Statement Find an equation for the plane that contains the point (1,-1,2) and the line x=t, y=t+1, z=-3+2t? 2. Homework Equations The Attempt at a Solution I don't know what I am doing wrong but everytime I try to do these plane questions my amswer is always the opposite sign of...
  49. maistral

    I Differentiating Vectors: Solve the Problem Now!

    Hi. I have this problem with differentiating vectors. Primarily because I have no experience at all (or whatsoever) about differentiating vectors. I am at a total loss here. I even have no idea regarding the difficulty of this (thus the [ I ] prefix). Please help me. How did the two equations...
  50. C

    Velocity Vectors and Navigation Across A River

    Homework Statement Sandra needs to deliver 20 cases of celery to the farmers' market directly east across the river, which is 32 meters wide. Her boat can move at 2.5 km/h in still water. The river has a current of 1.2 km/h flowing downstream, which happens to be moving in a southerly...
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