Curvilinear Definition and 87 Threads

Why are the coordinates seemingly used when the symmetry is around ##z## axis? Any particular reason why not ##x## or ##y##. In transforming from Cartesian to cylindrical form; I can see that ##z## is not considered when determining ##r##. Can we also use ##x## and ##z## assuming that the...

Hi, I was trying to gain an understanding of a proof of the divergence theorem in curvilinear coordinates. I have found these online notes here and am looking at the proof on pages 4-5. The method intuitively makes sense to me as opposed to other proofs which fiddle around with vector...

How I would have guessed you were supposed to solve it: What you are supposed to do is just take the gradients of all the u:s and divide by the absolute value of the gradient? But what formula is that why is the way I did not the correct way to do it? Thanks in advance!

The solution states that there's no rotational motion when ##C## is cut (the motion is curvilinear), so we can take torques with respect to the centre of mass of the plate. But, isn't it rotating? I think of it as a pendulum, which describes a circular motion. What's the difference? Wouldn't the...

Hi PF. I'm over ten years out from graduate school in physics, and I still enjoy re-reading my textbooks. I came across the word curvilinear, and thought how strange a word it is; a juxtaposition of curved and linear, which are at times understood to be opposites. The textbook was describing...

Hello, the physical domain in the (y, z) space is mapped to a rectangular computational region in the (ŋ,Ƹ)-space, where (ŋ,Ƹ) are the new coordinates. This technique frees the computational simulation from geometry restriction. after transforming the governing equations ( PDEs) to the...

I'm watching this lecture that gives an introduction to tensors. If we have a coordinate system that's an affine transformation of the Cartesian coordinate system, then the projection of a vector ##v## (onto a particular axis) is defined as ##v_m = v.e_m## or the dot product of the vector with...

Homework Statement A wedge with face inclined at an angle θ to the horizontal is fixed to a rotating turntable. A block of mass m rests on the inclined plane and the coefficient of static friction between the block and the wedge is µ. The block is to remain at position R from the centre of...

Homework Statement A weight is suspended from a spring 50 cm long and stretches it by 1 cm. Take the other end of the spring in your hand and rotate the weight in a horizontal plane so that the spring is stretched by 10 cm. What is the velocity of the weight? (The force with which the stretched...

I am trying to solve problems where I calculate work do to force along paths in cylindrical and spherical coordinates. I can do almost by rote the problems in Cartesian: given a force ##\vec{F} = f(x,y,z)\hat{x} + g(x,y,z)\hat{y}+ h(x,y,z)\hat{z}## I can parametricize my some curve ##\gamma...

I am beginning to study the mathematics of curvilinear coordinates and all textbooks and web sites do not have realistic examples of non-othogonal systems. What are some examples of non-orthoganal curvilinear coordinates so that I can practice on actual systems rather than generalized examples...

Homework Statement I’m studying orthogonal curvilinear coordinates and practice calculating differential operators. However, I’ve run across an exercise where the coordinate system is only in 2D and I’m confused about how to proceed with the calculations. Homework Equations A point in the...

1) Firstly, in the context of a dot product with Einstein notation : $$\text{d}(\vec{V}\cdot\vec{n} )=\text{d}(v_{i}\dfrac{\text{d}y^{i}}{\text{d}s})$$ with ##\vec{n}## representing the cosine directions vectors, ##v_{i}## the covariant components of ##\vec{V}## vector, ##y^{i}## the...

Hello everyone, In the COMSOL v5.1 doc i haven't found the mathematical description on how does the automatic geometry analysis or the curvilinear coordinates adaptive method (it is mentioned that they are similar) works. It would be convenient to have an idea about how does the Ecoil vector...

Homework Statement The mine skip is being hauled to the surface over the curved track by the cable wound around the 38-in. drum, which turns at the constant clockwise speed of 96 rev/min. The shape of the track is designed so that y = x2/28, where x and y are in feet. Calculate the magnitude of...

Homework Statement Is there a more intuitive way of thinking or calculating the transformation between coordinates of a field or any given vector? The E&M book I'm using right now likes to use the vector field ## \vec F\ = \frac {\vec x} {r^3} ## where r is the magnitude of ## \vec x...

In Weinberg's book, it is said that a given metric ##g_{\mu \nu}## could be describing a true gravitational field or can be just the metric ##\eta_{\alpha \beta}## of special relativity written in curvilinear coordinates. Then it is said that in the latter case, there will be a set of...

Homework Statement The system shown is initially at rest when the bent bar starts to rotate about the vertical axis AB with constant angular acceleration a 0 = 3 rad/ s2 . The coefficient of static friction between the collar of mass m = 2 kg and the bent bar is f.Ls = 0.35, and the collar is...

Hi guys, i can not understand something about curvilnear coordinates...from a "geometric" point of view what dose the componentes of the vector mean? in a non-curvilinear coordinates the components are the "projections" on along the bases but in a curvilinear coordinates the directions of the...

Hi, In an article on theoretical fluid dynamics I recently came across the following equation: $$M_i = \sqrt{g} \rho v_i$$ where ##M_i## denotes momentum density, ##v_i## velocity, ##\rho## the mass density and g is the determinant of the metric tensor. It is probably quite obvious, but I do...

The acceleration function of an object doing curvilinear motion is a = {(-0.2t)i+2j+1.5k} m/s^2, where t is in s. If its initial velocity v0 = 8i m/s, and initial position is at the origin, determine the magnitude of its velocity when t=3 s. Badly need your help guys. Thanks! All I see is ax...

Homework Statement Please refer to both figures. One has a picture and the other is the actual problem. Ignore the pencil writing on the figure as it was for a separate problem. Homework Equations aB+aA/B=aA vB+vA/B=vA an=v2rThe Attempt at a Solution I am actually really at a lost at the...

hi, I really wonder what the difference between curvilinear coordinates in a Euclidean space and embedding a curved space into Euclidean space is ? They resemble to each other for me, so Could you explain or spell out the difference? Thanks in advance...

1. Homework Statement Calculate the curvilinear integral ∫C (x2 + y2)ds where C is the line segment [0,0] → [3,4]. Then calculate the maximum M of x2 + y2 along the segment and verify that the inequality ∫C (x2 + y2)ds ≤ M*length(C) holds. Homework Equations ds = (x'(t)2 + y'(t)2)½dt ∇f(x,y)...

Homework Statement Homework EquationsThe Attempt at a Solution I have stared at this for hours and don't know where to start. I think I need to get r in terms of t but I don't really know how with the information given. I just need a good hint to get started.

Homework Statement Show that ##\nabla u_i \cdot \frac{\partial \vec r}{\partial u_i} = \delta_{ij}##. (##u_i## is assumed to be a generalized coordinate.) Homework Equations Gradient in curvilinear coordinates ##\nabla \phi = \sum_{i=1}^3 \vec e_i \frac{1}{h_i} \frac{\partial \phi}{\partial...

Homework Statement At the instant shown, the driver of the truck has just pressed the accelerator pedal down and the truck has suddenly acquired a tangential acceleration of 2.2m/s^2. Coefficient of static friction between crate and tray = 0.4 Coefficient of kinetic friction between crate and...

https://www.particleincell.com/2012/curvilinear-coordinates/ http://www.jfoadi.me.uk/documents/lecture_mathphys2_05.pdf Hi, I have a question about the curvilineare coordinate system. I wonder why is normal to the isosurfaces?isnt ei a tangent vector to the surface ui since "With these...

Same with problem https://www.physicsforums.com/threads/trigonometric-problem.76696/ . My problems here is I cannot came up with the same answers in the book. I didn't solve using vectors. Homework Equations I would like to know the equation on the 4th hint although I have different solution...

This problem is same as the problem on this link https://www.physicsforums.com/threads/trigonometric-problem.76696/ . I would like to ask the number 4 hint which is "4) We therefore have, for example the equality: " the equations can't be seen on my pc as it will only outputs this...

Homework Statement Show that the uvw-system is orthogonal. r, \theta, \varphi are spherical coordinates. $$u=r(1-\cos\theta)$$ $$v=r(1+\cos\theta)$$ $$w=\varphi$$ The Attempt at a Solution So basically I want to show that the scalar products between \frac{\partial \vec{r}}{\partial u}...

I have just been asked why we use curvilinear coordinate systems in general relativity. I replied that, from a heuristic point of view, space and time are relative, such that the way in which you measure them is dependent on the reference frame that you observe them in. This implies that...

Homework Statement Need to prove that: ,b means partial differentation with respect to b, G is the metric tensor and Γ is Christoffel symbol. I think I could proceed with this quite well if I could understand the hint given, that I should lower the index j. Homework Equations am=Gmjaj...

Hello, can you suggest a good book reference to find this: I have a 3D coordinate system where the axis are: 1) locally tangential to a spiral in the equatorial plane; 2) perpendicular to 1 in the equatorial plane; 3) colatitude. The direction of axes 1 and 2 changes with position. I need to...

I have a system of forces which I have reduced to a force-couple system. I am trying to predict the motion of the force and couple. This is hard because the force changes direction as the moment turns the particle. I imagine this should be turned into some sort of tangential-normal components...

This paper is about momentum operator in curvilinear coordinates. The author says that using \vec p=\frac{\hbar}{i} \vec \nabla is wrong and this form is only limited to Cartesian coordinates. Then he tries to find expressions for momentum operator in curvilinear coordinates. He's starting...

Homework Statement As a part of my self study I am trying to find the covariant basis vectors in the spherical polar coordinates. Since I have never done anything like this before I would appreciate if someone could tell me whether I am on the rigth track. Homework Equations...

The position vector ##\vec{r}## in cartesian coordinates is: ##\vec{r} = x \hat{x} + y \hat{y}##, in polar coordinates is: ##\vec{r} = r \hat{r}##. But, given a curve s in somewhere of plane, with tangent unit vector ##\hat{t}## and normal unit vector ##\hat{n}## along of s, exist a definition...

Hellow everybody! If ##d\vec{r}## can be written in terms of curvilinear coordinates as ##d\vec{r} = h_1 dq_1 \hat{q_1} + h_2 dq_2 \hat{q_2} + h_2 dq_2 \hat{q_2}## so, how is the vectors ##d^2\vec{r}## and ##\vec{r}## in terms of curvilinear coordinates? Thanks!

Hello, if we consider a diffeomorphism f:M-->N between two manifolds, we can easily obtain a basis for the tangent space of N at p from the differential of f. I was wondering, why should we always express tangent vectors as linear combinations of tangent basis vectors? Could it be useful in...

Homework Statement a) Prove that m (d^2s/dt^2) = Ftang, the tangential component of the net force on the bead. [hint] one way to do this is to take the time derivative of the equation v^2=v(dot)v. The left side should lead you to (d^2s/dt^2), and the right side should lead to Ftang. b)...

Hello, let's assume we have an admissible change of coordinates \phi:U\rightarrow \mathbb{R}^n. I would like to know how the inner product on ℝn changes under this transformation. In other words, what is \left\langle \phi (u), \phi (v) \right\rangle for some u,v \in U ? I thought that...

To specify a vector in cartesian coordinate systems,we assume its tail to be at the origin and give the cartesian coordinates of its head.What about other coordinate systems? For example,in spherical coordinates,is the following correct? a \hat{x}+b \hat{y}+c \hat{z}=\sqrt{a^2+b^2+c^2}...

Homework Statement What is the magnitude of the velocity at t=4.00s? I would like to see if my approach and answer is correct. Homework Equations Position: r = {-30cos(\frac{\pi}{10}t) i + 30sin(\frac{\pi}{10}t) j - (7t) k} ft The Attempt at a Solution I took the first...

Homework Statement A pin is constrained to move in a circular slot of radius 39mm. At the same time a slotted bar also constrains the pin to move down with constant velocity 8mm/s. (as shown in attached diagram). What is the magnitude of the acceleration of the pin for the position...

Hello, let's suppose I have the following system of curvilinear coordinates in ℝ2: x(u,v) = u y(u,v) = v + e^u where one arbitrary coordinate line C_\lambda(u)=u \mathbf{e_1} + (\lambda+e^u) \mathbf{e_2} represents the orbit of some point in ℝ2 under the action of a Lie group. Now I consider...

How to express electromagnetic field tensor in curvilinear coordinates, that is given a curvilinear coordinates (t,\alpha,\beta,\gamma) with metric tensor as follows: n_{\mu \nu }= \left[ \begin{array}{cccc}h_0^2& 0 & 0 & 0 \\ 0 & -h_1^2 & 0 & 0 \\ 0 & 0 & -h_2^2 & 0 \\ 0 & 0 & 0 & -h_3^2...

HI there. Some days ago, whyle studying vector mechanics I came across with a rather dazzling doubt. Why isn't there angular velocity and accelaration in a curvilinear translation? Imagine, a small planet in a perfect circular orbit around a star. Let's say, the planet has no form of...

Wikipedia gives the relationship between a cartesian and curvlinear coordinate system as gi=(partial)x1/(partial)zi +(partial)x2/(partial)zi http://en.wikipedia.org/wiki/Curvilinear_coordinates Where gi is the i'th basis in the curvlinear coordinate system, x1 and x2 are the cartesian...

Homework Statement The car passes point A with a speed of 25 m/s after which its speed is defined by V = (25-0.15s)m/s. Determine the magnitude of the car's acceleration when it reaches point B, where S = 51.5 m. (the max height of the hill is 16 m, and the function of the hill the car is...