Curl Definition and 359 Threads

  1. M

    Rules for curl test applicability

    trying to remember rules for curl test applicability. is it just simple closed curve? is F=-ysin(x)i+cos(x)j able to use the curl test?
  2. K

    "Showing E&B Obey Wave Equation w/ Maxwell's Curl

    Homework Statement This question is closely related to physics but it's in a maths assignment paper i have so here it is: By taking curls of the following equations: \nabla \times \bf{E} = -\frac{1}{c}\frac{\partial\bf{B}}{\partial t} \nabla \times \bf{B} =...
  3. F

    How Does Stokes' Theorem Apply to a Triangular Contour in Vector Calculus?

    Homework Statement Assume the vector function A = ax(3x^{2}2y^{2})-ax(x^{3}y^{2}) a) Find \ointA\cdotdl around the triangular contour shown in Fig. 2-36 [it is a triangle with base and height of one on the x and y axis. the curl travels so that the normal vector is in the -z direction] b)...
  4. M

    Find \nabla x curl E: Solve Using Properties of Vector Calculus

    given curl E = -1/c*(\partialH/\partialt) div E = 0 div H = 0 curl H = 1/c*(\partialE/\partialt), find \nabla x (\nabla x E) how do i take \nabla x curl E? i tried to do it by determinants, but I'm not sure which values correspond to the i, j, and k. so my next assumption is that there...
  5. L

    Calculate Div & Curl from V=Kyi-Kxj

    Determine Div & Curl from a given vector field V=Kyi-Kxj How do I format this? It's been a while since I've done this and every divergence and curl example I look up has the format V(x,y,z)={V1(x,y,z);V2(x,y,z);V3(x,y,z)} Should I reformat my V to be V{x,y}={V1(x,y);V2(x,y)}={Ky,-Kx}...
  6. I

    Inverse of Curl Operator: A as a Function of B?

    I want to express A as a function of B in the following equation: curl{A}=B So I need the inverse of the curl operator, but I don't know if it exist. Thanks.
  7. C

    Definition of Curl. Can anyone derive the gradient operator?

    "Definition" of Curl. Can anyone derive the gradient operator? Can anyone prove why this equality is true? http://en.wikipedia.org/wiki/Curl_%28mathematics%29#Definition Wikipedia says it is defined, however that's BS since the gradient operator was already defined so this needs to be proven...
  8. M

    What's the causal model for direction of curl of magnetic field lines?

    untruncated version of question: As electrons move through a wire, is the direction of the curl of the magnetic field lines observed derivable from an underlying property? =========================== more detail (only to further clarify my question as useful): > looking for a mechanistic...
  9. H

    The curl of certain vector fields

    Given the two vector fields: \vec E and \vec B Where the first is the electric vector field and the second is the magnetic vector field, we have the following identity: curl(\vec E) = -\frac{\partial \vec B } { \partial t } and further that: curl(curl(\vec E)) =...
  10. E

    Understanding Scalar Fields: Div, Curl, RotGrad & DivGrad

    Curl div... Homework Statement f is a scalar field. What does div(f) curl(f) rotgrad(f) divgrad(f) stand for? I need to know if a scalar field can have the meanings of roration and diverge like a vector field
  11. H

    A Div, Grad, Curl and all that book for waves?

    Hello, I find that one of my biggest weakness is following along with the math of waves (Wave function, SHO, Schrödinger Equation, etc). Is there a book out there that gives treatment to wave functions and PDE's in the same way that Div, Grad, Curl does for multi var/vector calculus? I do...
  12. U

    Understanding Divergence & Curl of Vector Fields

    I know how to calculate the divergence and curl of a vector field. What I am lacking is any intuition on what these values mean. example: V= {x, y, z} ∇.V = 3 ∇xV = {0,0,0} F={-y, x, 0} ∇.F = 0 ∇xF = {0,0,2} G={0, 3y, 0} ∇.G = 3 I understand that that the divergence is a measure of how much...
  13. E

    Gradient and curl of an oil spill be?

    could someone please help me? what would the divergence, gradient and curl of an oil spill be? I'm a bit confused. Thank you
  14. C

    Integrals with curl dot products

    Homework Statement 1. Evaluate \int_{S}\int curl F \cdot N dS where S is the closed surface of the solid bounded by the graphs of x = 4, z = 9 - y^2, and the coordinate planes. F(x,y,z) = (4xy + z^2)i + (2x^2 + 6y)j + 2xzk 2. Use Stokes's Theorem to evaluate \int_{C}F\cdot T dS...
  15. J

    Can Curl V Determine V? A Method for Finding Vector Fields

    Say V is a vector field. Is there a way (or rather a reasonable algorithm) to find V, given Curl V? Thanks
  16. G

    Solving a Cylindrical Curl Integral Question

    Homework Statement Question Attached Homework Equations The Attempt at a Solution So here I'm attempting b), I know \nabla \times \vec F\ is the curl, which in this case is defined by the matrix \left[ \begin {array}{ccc} x&y&z\\ \noalign{\medskip}{\frac {d}{{\it dx}}}&{\frac {d}{{\it...
  17. N

    Flux integral of a curl = zero

    Does Stokes's theorem imply that the flux integral of a curl of a vector field over a closed surface is always zero? (because then there is no boundary curve and thus the line integral over the boundary curve is zero) Is there an insightful way to see why this is always true? Maybe a...
  18. T

    Is There a Relationship Between a Vector Field's Divergence and Its Curl?

    Is this a theorem, that for a vector field B satisfying div B = 0 everywhere then there is a vector field A such that B = curl A? If so, is it hard to prove? Of course, the converse is obviously true.
  19. L

    What Do Divergence and Curl Reveal About Vector Functions in Electromagnetism?

    What do Divergence and Curl of a vector function actually mean? They are nice to understand as mathematical operators and then we can work on with them, but what do they mean physically and why are they so important in our study of electromagnetism?
  20. J

    Calculate curl of rotating bucket of water

    Homework Statement A bucket of water is rotated slowly with angular velocity w about its vertical axis..When a steady state has been reached the water rotates with a velocity field v(r) as if it were a rigid body. Calculate div(v) and interpret the result. Calculate curl (v). Can the flow be...
  21. U

    How do we define and calculate divergence in vector fields?

    I have some conceptual problems with divergence... 1.divergence is supposed to be the flux per unit volume at a particular point...again,I saw on wikipedia,that they define divergence as "the derivative of net flow of of the vector field across surface of a small region relative to the volume...
  22. S

    Can You Determine a Vector if Its Curl is Given?

    Is it possible to find the vector when its curl is known?
  23. L

    Is Curl a Measure of Circulation Tendency?

    When studying the curl, one often finds the explanation that the curl is a measure of the tendency of a vector field to circulate around a given point. But this doesn't make much sense to me, since there's no clear way to measure "tendency"? What are the units of "tendency"? Wouldn't you agree...
  24. Z

    Finding A for B Using Gradient and Curl

    Hello everyone! Having a field \bf B = \nabla \times \bf A , how is it possible to get \bf A ? For constant fields, the answer is easy, but is there a general approach to find A ? Some algorithm to do it numerically would help me immensly, too. If anyone knows some book or reference...
  25. G

    Answer "Find Divergence & Curl of Vector Field A

    Homework Statement find the divergence and curl of the vector field A = (x/(\sqrt{x^2 + y^2 + z^2}))i + (y/(\sqrt{x^2 + y^2 + z^2}))j + (z/(\sqrt{x^2 + y^2 + z^2}))k Homework Statement The Attempt at a Solution Im not going to go through the whole lot but i have done the whole...
  26. T

    Curl of the transpose of a gradient of a vector: demonstration of an identity

    I would like to demonstrate an identity with the [SIZE="4"]INDICIAL NOTATION. I have attached my attempt. Please let me know where I made mistakes. Any suggestion? I am trying to understand tensors all by myself because they are the keys in continuum mechanics Thanks
  27. I

    Curl of an electric dipole field

    Is the field of an electric dipole conservative? Initially I thought it would be, for no particular reason but that's just what my high school intuition thought. (haha I thought everything would be conservative apart from friction) But I was reading up on some vector calculus and...
  28. Y

    About the curl of B using Biot-Savart Law

    I am reading the Griffiths about finding the curl of B using Biot-Savart Law. I do not understanding the step between equation (5.52) and (5.53) which finding the x components of the following: (\boldsymbol{J}\cdot\nabla^{\prime})\dfrac{\hat{\xi}}{\xi^{2}} where...
  29. P

    Generalizing: Curl of a Function

    Hello. I have tried to search all day for the answer to my question but could not find anything. Is there a way to generalize the curl of a vector field to dimensions greater than three? It seems pretty straightforward to find the gradient and divergence of higher dimensional vector fields...
  30. R

    Curl Problem Homework: Solution & Tips

    Homework Statement Homework Equations The Attempt at a Solution I think for solving this problem I should write \vec{r}=(x,y,z) and \vec{m}=(m_{x},m_{y},m_{z}) and then do a lot of algerbra to work it out. Is it correct? Is there a better/another solution?
  31. J

    Calculating Forces and Potential Energy Changes: Integrals, Curl, and Work

    Homework Statement U(x,y) = 3x2 - 7y A) Calculate the force at the coordinate point (3,3) B) Determine if the following forces are conservative and find the change in potential energy correspoinding to each for an interval 0 to x i) Fx = ax + bs2 a and b are constants ii) Fx =...
  32. B

    Question regarding Curl and Cross Product

    I'm studying vector calculus, and have a question about the curl and its relation to a cross product of the del operator and a vector. When doing a standard cross product as the formula I have i(det1) - j(det2) + k(det3), where det1, 2 3 are the appropriate 2x2 determinants. However for the...
  33. A

    Evaluate the divergence and curl of the following vector

    Homework Statement Evaluate the divergence and curl of the following vectors. A(r) is everywhere parallel to the y-axis with a magnitude A = cx + A0 , where c and A0 are constants. Homework Equations The Attempt at a Solution I can evaluate the div and curl, but i don't know...
  34. V

    How Do You Compute the Curl and Vectorial Laplacian of a Radial Function?

    Homework Statement I want to calculate \nabla\times[\vec{F}(r)] and \nabla^2[\vec{F}(r)] where F if a function that depends of r, and r = \sqrt{x^2+y^2+z^2} Homework Equations 1)\nabla \times \vec A = \left|\begin{matrix} \mathbf{\hat{i}} & \mathbf{\hat{j}} & \mathbf{\hat{k}} \\ \\...
  35. S

    Question concerning curl for finding a conservative force field

    Hello all, I understand the fact that the principles LaTeX Code: F= \\nabla \\phi . LaTeX Code: \\nabla \\times F = 0 . must apply in order for a force field to be conservative however what i don't get is why showing: LaTeX Code: f_y= g_x, f_z= h_x, g_z= h_y where subscripts are what you...
  36. A

    Curl of E for Charged Particle: Possibility?

    like the divergence of a charged particle (whether + or -) Is there any possibility of presence of curl of elctric field of that particle?
  37. J

    Curl of - \frac{1}{\rho} \vec \nabla p

    I'm trying do derive the vorticity equation \begin{align}\frac{D\vec\omega}{Dt} &= \frac{\partial \vec \omega}{\partial t} + (\vec V \cdot \vec \nabla) \vec \omega \\ &= (\vec \omega \cdot \vec \nabla) \vec V - \vec \omega (\vec \nabla \cdot \vec V) + \frac{1}{\rho^2}\vec \nabla \rho \times...
  38. N

    Is a Magnetic Field B with Curl B = 0 Possible?

    Hi, Is it possible to have a magnetic field B which has curl B = 0 in all space? intuitivly such a field will be in a constant direction (like the electric field of an infinite charged plate ) and magnetic field "don't behave" like that, they make circles around currents, but this is not...
  39. F

    What are some examples of fields with equal divergences and different curls?

    Find a pair of fields having equal and divergences in some region, having the same values on the boundary of that region, and yet having different curls. I really have no idea on where to start for this. Would making up 2 arbitrary fields in spherical co-ordinates work? a(theta) + b\phi +...
  40. R

    Div Curl: Black Hole Edge Explored

    What is the divergence and curl at the edge of a black hole?
  41. J

    Definition of Curl - Explaining Nabla x V = -k Partial Phi/Partial t a_n

    Homework Statement Can someone explain the following to me, \nabla x \vec{V} = -k \frac{\partial{\Phi}}{\partial{t}} \hat{a}_n where \vec{V}, \Phi are the wind velocity and pressure respectively.Homework Equations Take the cross product- thus in the matrix we have the unit vectors in the first...
  42. R

    Does Zero Volume Indicate Zero Curl in Vector Fields?

    Regarding the equation for curl: Nable E literally means the sum of the differences of certain rates of change with respect to certain coordinates i hat, j hat, k hat. Since Nabla Cross E also is interpreted as the volume of a paralleliped in 3D space... 1. when the volume is zero, does...
  43. H

    Gauss' Theorum and curl of a vector field

    Two problems one that I have some idea about solving, the other I have no idea at all about where to start. 1. Find the surface integral of E . dS where E is a vector field given; E = yi - xj + 1/3 z3 and S is the surface x2 + z2 < r2 and 0 < y < b Well Gauss' theorum would be the place...
  44. D

    Finding the curl and divergence

    Homework Statement \vec{F}(x,y,z) = x^2y\vec{i} + y^2z^3\vec{j} + xyz\vec{k} Homework Equations The Attempt at a Solution I got: Curl: (xz - 3y^2z^2)\vec{i} + (-yz)\vec{j} + (-x^2)\vec{k} Div: 2xy + 2yz^3 + xy Are these right?
  45. C

    Divergence and Curl of Unit Vectors?

    Homework Statement http://img4.imageshack.us/img4/4218/divergenceandcurl.jpg The Attempt at a Solution Totally confused on what the question's asking. Wouldn't the divergence of say x_hat be the partial of x_hat over x which is just 0? So every answer would just be 0 or something? Same...
  46. E

    Finding the Curl of a Vector Field

    Homework Statement http://img5.imageshack.us/img5/8295/capturewmw.th.jpg Homework Equations The Attempt at a Solution I tried to find the curl first and what i got is y - 3 and then I multiply that by the area of the circle which is 4pi.. am I doing something wrong?
  47. A

    Understanding Curl: How to Evaluate Line Integrals and Taylor Expansions

    Hello All .. How are you ? I hope you fine Our professor taught as about the meaning of curl , but I was totally confused about it , especially when he used Taylor expansion of two variables and line integrals It’s like this Sorry for the very bad diagram in attachments , where delta...
  48. S

    Can I derive an equation for a vector field's divergence from its curl equation?

    Given an equation describing the curl of a vector field, is it possible to derive an equation for the originating vector field? The divergence of the field is known to be zero at all points
  49. S

    Maxwell's Equations: Find Magnetic Field from Curl

    I'm working with Maxwell's equations, and I have found the curl of a magnetic field at all points. How can I figure out what the magnetic field is at those points?
  50. L

    Determining Field from Div & Curl: Examples & Techniques

    My notes say that if we know the divergence and curl of a field then that uniquely determines the field. Can somebody give me an example of how, given only the div and curl of a field, we can deduce the field? I considered the electric field where we have, \nabla \cdot...
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