Vector Definition and 1000 Threads

  1. T

    I Understanding Vectors: Magnitude & Direction

    Good Morning (And apologies if this is not the right forum -- it is not a homework problem.) On the one hand, a vector is an arrow and a tail: it has magnitude and direction. It is used to describe direction, forces, acceleration, etc. However, there are more mathematical definitions: a...
  2. CaliforniaRoll88

    Multi-part question involving a vector field

    (a) ##\vec G=24xy\hat a_x+12(x^2+2)\hat a_y+18z^2\hat a_z## @ ##P(1,2-1)## ##\vec G=24(1)(2)\hat a_x+12(1^2+2)\hat a_y+18(-1)^2\hat a_z## ##\vec G=48\hat a_x+36\hat a_y+18\hat a_z## (b) I am not sure how to get this part started. Could someone point me in the right direction?
  3. chiyu

    I Vector calculus: line element dr in cylindrical coordinates

    We were taught that in cylindrical coodrinates, the position vector can be expressed as And then we can write the line element by differentiating to get . We can then use this to do a line integral with a vector field along any path. And this seems to be what is done on all questions I've...
  4. M

    Finding vectors parallel to a given vector

    For (b) of this problem, The solution is, However, I am confused why the two parallel vectors are ##(\frac{2}{\sqrt{13}}, \frac{3}{\sqrt{13}})## and ## (-\frac{2}{\sqrt{13}}, -\frac{3}{\sqrt{13}}) ## should it not be ##(2,3)## and ##(-2,-3)##. Do somebody please know why they wrote that? Also...
  5. whartung

    I Solving simultaneous vector equations

    I'm sorry, this touches so many areas, I just didn't know which pigeon hole to put it in, so I dropped it here in General. Simple summary. I have two physics equations. The problem I'm trying to solve is a follower is chasing a target that is moving at a fixed velocity. The follower is going...
  6. C

    Does each norm on vector space become discontinuous when restricted to S^1?

    Dear Everybody, I am having trouble with last part of this question. I believe the answer is no. But I have to proof the general case. Here is my work for the problem: Suppose that we have two distinct norms on the same vector space ##X## over complex numbers. Then there exists no ##K## in...
  7. entropy1

    B How to multiply matrix with row vector?

    How do I calculate a 3x3 matrix multiplication with a 3 column row vector, like below? ## \begin{bmatrix} A11 & A12 & A13\\ A21 & A22 & A23\\ A31 & A32 & A33 \end{bmatrix}\begin{bmatrix} B1 & B2 & B3 \end{bmatrix} ##
  8. M

    Vector Calculus in 1D: ± to Show Magnitude?

    [mentor's note - moved from one of the homework help forums] Homework Statement:: It's a question. Relevant Equations:: Vector calculus. Is it true to say that in one dimension I can show vector quantities using ±number instead of a vector? ± can show possible directions in one dimension and...
  9. O

    I Dot product of two vector operators in unusual coordinates

    Hi. I hope everyone is well. I'm just an old person struggling to make sense of something I've read and I would be very grateful for some assistance. This is one of my first posts and I'm not sure all the LaTeX encoding is working, sorry. Your help pages suggested I add as much detail as...
  10. sHatDowN

    Vector sample problem -- Force components on a spring mechanism

    Determine the amount and type (tensile or compressive) of the spring force so that the resulting force is a vertical force. Also get the resultant force. i find 60N (compressive) and resultant forces is 10800 is that correct?
  11. sHatDowN

    Vector problem, magnitude of the force

    Member CB of the vise shown exerts on block B a force P directed along line CB. Knowing that P must have a (1237) N horizontal component, determine (a) the magnitude of the force P, (b) its vertical component i don't get it what the "N horizontal component"
  12. sHatDowN

    Simple Addition of Vector Forces on an Eye-Hook

    The screw eye is subjected to two forces, F1 and F2. Determine the magnitude and direction of the resultant force.
  13. R

    A Converting this vector into polar form

    In the following%3A%20https://pubs.rsc.org/en/content/articlehtml/2013/sm/c3sm00140g?casa_token=3O_jwMdswQQAAAAA%3AaSRtvg3XUHSnUwFKEDo01etmudxmMm8lcU4dIUSkJ52Hzitv2c_RSQJYsoHE1Bm2ubZ3sdt6mq5S-w'] paper, the surface velocity for a moving, spherical particle is given as (eq 1)...
  14. R

    Sum of angles with x,y and z axis made by a vector

    I want to know if there is any proper relation between the angles of a vector with the three dimensional coordinate axes, if the angles are ,α , β and γ, will the sum of α, β and γ be 180 degress that is α + β + γ = 180°,m finding the same to be true in a 2 D case where α + β = 90° and γ =...
  15. G

    I 4-Current vector potential transformation under Gauge fixing

    I am given an initial vector potential let's say: \begin{equation} \vec{A} = \begin{pmatrix} g(t,x)\\ 0\\ 0\\ g(t,x)\\ \end{pmatrix} \end{equation} And I would like to know how it will transform under the Lorenz Gauge transformation. I know that the Lorenz Gauge satisfy...
  16. P

    C/C++ Overload functions by dimension of vector

    vector<OP> negate (vector<OP> a) { a.insert(a.begin(), neg); return a; } vector<vector<OP>> negate (vector<vector<OP>> a) { for (int i=0; i<a.size(); i++) a[i] = negate(a[i]); // reference to 'negate' is ambiguous? return a; } OP is an enum here. Why can't C++...
  17. H

    Unitary vector commuting with Hamiltonian and effect on system

    Hi, I'm not sure to understand what ##| \phi_n \rangle = \sum_i \alpha_i |\psi_n^i## means exactly or how we get it. From the statement, I understand that ##[U,H] = 0## and ##H|\psi_n \rangle = E_n|\psi_n \rangle## Also, a linear combination of all states is also an solution. If U commutes...
  18. K

    How Can We Prove the Conjugate Transpose Property of Complex Matrices?

    TL;DR Summary: For every Complex matrix proove that: (Y^*) * X = complex conjugate of {(X^*) * Y} Here (Y^*) and (X^*) is equal to complex conjugate of (Y^T) and complex conjugate of (X^T) where T presents transponse of matrix I think we need to use (A*B)^T= (B^T) * (A^T) and Can you help...
  19. binbagsss

    I Using the Chain Rule for Vector Calculus: A Tutorial

    This is probably a stupid question, but I have never realised that there's an order things should be done in the chain rule , so for example ## \nabla(\bf{v}.\bf{v})=2\bf{v} (\nabla\cdot \bf{v}) ## and not ## 2 \bf{v} \cdot \nabla \bf{v} ## Is there an obvious way to see / think of this...
  20. M

    Discovering Vector Direction in Conservation of Energy Problems

    For this problem, Is the length vector into or out of the page and how do you tell? EDIT: Why must we use conservation of energy for this problem? I tried solving it like this: ##IdB\sin90 = ma ## ##IdB = ma ## ##v_f = (2aL)^{1/2} ## ##v_f = (\frac {2dIBL} {m})^{1/2} ## Which is incorrect...
  21. S

    I Can time be another basis vector under Galilean relativity?

    I refer to the video of this page, where there is a description of Galilean relativity that is meant to be an introduction to SR, making the comprehension of the latter easier as a smooth evolution from the former. All the series is in my opinion excellent, but I think that this aspect is...
  22. nataelp

    Force between 2 point charges in VECTOR format (x i + y j + z k)

    I tried using the distance between r2 and r1 and plugging them into the equation for i, j, k. >> So for the force in the x direction it was k*(4E-6*4E-6)/(4-9)^2. The answer I got was wrong according to webassign. Can someone please tell me what I am missing?
  23. chwala

    Solve the given vector problem

    This is an international past paper question- I have attached the question and the markscheme... the ms was a bit confusing for 2 marks hence my post. Question; interest is on part iii. only Mark scheme solution; My thinking; Let ##OD=λOA## Where ##λ## is a scalar. ##OD=λ...
  24. J

    Two vector operations and simple expressions

    TL;DR Summary: My problems comes to a vector expression which needs to be simplified I got an expression pi=εijksk,lul,j Here s and u are two vectors. What will be the vector expression of this vector p with curl s, curl u, and other operations?
  25. K

    I Multiplying three vector operators

    Given vector operators as $$\mathbf{A} = (A_{1}, A_{2} ,A_{3}) $$ $$\mathbf{B} = (B_{1}, B_{2} ,B_{3}) $$ $$\mathbf{C} = (C_{1}, C_{2} ,C_{3}) $$ I know that for two vector operators $$\begin{equation} \mathbf{Q} \mathbf{P} = \sum_{\alpha = 1}^{3} Q_{\alpha} P_{\alpha} \end{equation}$$...
  26. P

    I Vector Potential Multipole Expansion

    when you do a multipole expansion of the vector potential you get a monopole, dipole, quadrupole and so on terms. The monopole term for a current loop is μI/4πr*∫dl’ which goes to 0 as the integral is over a closed loop. I am kinda confused on that as evaulating the integral gives the arc length...
  27. heroslayer99

    Suvat vector versus the scalar form

    Hi I was just wondering about the suvat formulae and a question popped into my head, which I'd like someone to try and explain the reason as to why please. So I know that when we have a formula such as F=ma or v = u + at, you can evaluate the magnitude of both sides and arrive at a scalar...
  28. P

    A Vector calculus - Prove a function is not differentiable at (0,0)

    ##f\left(x\right)=\begin{cases}\sqrt{\left|xy\right|}sin\left(\frac{1}{xy}\right)&xy\ne 0\\ 0&xy=0\end{cases}## I showed it partial derivatives exist at ##(0,0)##, also it is continuous as ##(0,0)## but now I have to show if it differentiable or not at ##(0,0)##. According to answers it is not...
  29. Addez123

    Can't find potential of vector field

    1. To find the solution simply integrate the e_r section by dr. $$\nabla g = A$$ $$g = \int 3r^2sin v dr = r^3sinv + f(v)$$ Then integrate the e_v section similarly: $$g = \int r^3cosv dv = r^3sinv + f(r)$$ From these we can see that ##g = r^3sinv + C## But the answer is apparently that there...
  30. Onyx

    B Calculate Unit Normal Vector for Metric Tensor

    How do I calculate the unit normal vector for any metric tensor?
  31. Haorong Wu

    A Propagation Vector of Light in Kerr Spacetime: Reference Needed

    Hi, there. I am currently reading the paper, Gravitational Faraday rotation induced by a Kerr black hole (https://doi.org/10.1103/PhysRevD.38.472). After Eq. (2.4), it reads that The paper does not provide the derivation of the equations and no related reference is listed. Also, ##k^i## is not...
  32. K

    Normalize function - quantum chemistry

    Normalize function f(r) = Nexp{-alpha*r} Where alpha is positive const and r is a vector I was just wondering if the fact that we have a vector value in our equation changes anything about the solution
  33. L

    Solving a Celestial Mechanics Task with Velocity Vector Scattering

    Hi, the task is as follows Unfortunately, I am not getting anywhere at all with task c. I have now proceeded as follows: I assume that the calculation takes place in the reference system of the sun. In the task the following is valid, $$\vec{v}_{si}=-s\vec{v}_p$$ I have now simply assumed...
  34. A

    I Explicit non-local form for the vector potential?

    Hello everyone, I was looking at the light matter interaction Hamiltonian and I worked out a simple calculation where I was surprised to see that I had to introduce an explicitly non-local vector potential if I want to go further: $$\langle\psi|...
  35. A

    I Determining elements of Markov matrix from a known stationary vector

    Hi, For a 2 x 2 matrix ##A## representing a Markov transitional probability, we can compute the stationary vector ##x## from the relation $$Ax=x$$ But can we compute ##A## of the 2x2 matrix if we know the stationary vector ##x##? The matrix has 4 unknowns we should have 4 equations; so for a ##A...
  36. homeworkhelpls

    I What does vector subtraction for two non-perpendicular vectors look like?

    vector subtraction of ppl is simple but i cant visualise the subtraction please help
  37. josephsanders

    High Energy Literature for introduction to O(N) vector model

    TL;DR Summary: Looking for literature on O(N) vector model Hello, We have been going over the O(N) vector model in my QFT class but the notes are not very detailed and we are not using a textbook. Does anyone know of a good QFT book which goes over this material? I have a copy of Shrednicki...
  38. A

    I What are the applications of inverses of vector functions?

    As an example, consider a vector-valued function of the form ##f(x,y) = (g_1(x,y),g_2(x,y))##. I typed up one example on wolfram to see if this could be visualized https://www.wolframalpha.com/input?i=plot+f(x,y)+=+(x+y,xy) which was inspired by this question...
  39. D

    I Prove $$T_{p}M$$ is a vector space with the axioms

    Suppose M is a manifold and $$T_{p}M$$ is the tangent space at a point $$p \in M$$. How do i prove that it is indeed a vector space using the axioms: Suppose that u,v, w $$\in V$$. where u,v, w are vectors and $$\V$$ is a vector space $$u + v \in V \tag{Closure under addition}$$ $$u + v = v +...
  40. A

    B Turn one vector into another vector

    This might seem like a novice question, but let's suppose we have a vector ##x## and we want to turn it into vector ##y##. Well, what square matrix multiplied on ##x## accomplishes this? As an example, let's work with a ##2 \times2## case: ##x = \begin{bmatrix} x_1 \\ x_2 \end{bmatrix}## and...
  41. homeworkhelpls

    Question about vector coordinates

    here i found AB to be (-3, 2) and then i thought to do 2/5 multiplied by AB to find AC, however this is incorrect and instead i would have to involve the origin. Why and how can i involve the origin?
  42. homeworkhelpls

    Calculate the position vector for 3di

    for 3di i did the normal AB=BC so b-a would give either satisfy or not this phenomenon, my answer was (3a-1, -4) & (2a^2 + a - 1, 4a - 2), now how would i know from here if they're collinear or not?
  43. homeworks

    Vector questions with X and Y Components

    I know what x and y components are but this is really confusing me. And the angle I think is the inverse of tan something. part 3 is so confusing smh
  44. S

    Differential equation of vector field

    I was thinking of using the chain rule with dF/dx = 0i + (3xsin(3x) - cos(3x))j and dF/dy = 0i + 0j but dF/dy is still a vector so how can it be inverted to get dy/dF ? what are the other methods to calculate this?
  45. J

    Linear operator in 2x2 complex vector space

    Let C2x2 be the complex vector space of 2x2 matrices with complex entries. Let and let T be the linear operator onC2x2 defined by T(A) = BA. What is the rank of T? Can you describe T2? ____________________________________________________________ An ordered basis for C2x2 is: I don't...
  46. T

    A Contravariance, Covariance, stress and position vector

    Good Morning! I understand that a vector is a physical object I understand that it is the underlying basis that determines how the components transform. However, I encounter this: https://en.wikipedia.org/wiki/Covariance_and_contravariance_of_vectors The fifth paragraph has this statement A...
Back
Top