Surface Definition and 1000 Threads

I really have no idea how to approach this question, I was thinking write ##F=mg## but I am not sure if I can write that even though

Do you thing swift birds(most aerodynamics birds; 10months in the air without landing,fastest birds in horizontal flapping flight -169km/h) have some benefits of overlaping feathers which gives rough surface? Can planes benefits from...

Please help to see whether it's correct to do in this way

I am not clearly understand what the question requests for, is it okay to continue doing like this ? Kindly advise, thanks

I was looking for on the internet for a while without a success. If I know that the surface tension of pure oil is ##\gamma_o=A## and I know that the surface tension of pure water is ##\gamma_w=B## so if I have a mixture of water and oil with surface tension ##\gamma_m=C## am I able to know...

A water drop of radius ##10^{-2}## m is broken into 1000 equal droplets. Calculate the gain in surface energy. Surface Tension of water is ##0.075 ~N/m##. So, for the solution of the above problem we need to know how much surface area (combining all 1000 droplets) have increased from the...

I came across this diagram, the ##\gamma##'s are supposedly forces per unit length of the respective interfaces: It's not clear what these forces are acting on. ##\gamma_{SL}## and ##\gamma_{LG}## look like they could be acting on a small bit of water right at the end, but I have no idea what...

Suppose we have placed a cube in field which varies linearly with z axis so electric field magnitude on coordinates of face ABCD is clearly more than face EFGH and we know area of both faces are equal, So if we calculate flux then it would be non zero but it contradicts with the fact that...

Hi all, I hope this is the correct place to post this. Below is a section of a pipe. The pipe has a radius of 0.848 m. For this example, assume the pipe is buried below ground but a section of it remains exposed. The centre of the pipe is buried 0.590 mbelow the ground. If we assume the pipe...

I've learned that the surfaces of places like the moon and the surfaces on Mars corresponding to the Noachian period signify relatively old surfaces because weathering and erosion tend to make those cratered surfaces smooth. However, I heard a professor mention that this is also true for icy...

When 2 conductors/dielectrics touch, will surface charges move away from their original conductor/dielectric to the other?

Hi to everyone, do you know the "One World Trade Center"? Well, I've to calculate two things about it: -The volume, according to its particular shape -The surface of the glass plates which cover the whole structure Searching on internet i found two dimensions: 1) Total height without...

In Stokes' theorem, the closed line integral of f=the surface integral of curl f on ANY surface bounded by the same curve. But in Gauss' theorem, the surface integral of f on a surface=the volume integral of div f on a unique volume bounded by the surface. A surface can only enclose 1 volume...

This should maybe go in the Beyond The Standard Model forum but since it's a paper about quantum cosmology I'll put it here. Feel free to move it if it's too speculative but that's exactly my question. That is: if it is... Perusing "The Area of a Rough Black Hole" - -...

Summary:: For finding the electric field at P in the photo below, may I select a gaussian surface circular? [Mentor Note -- thread moved to the schoolwork forums, so no Homework Template is shown]

Hi, I have a problem with inclined planes. The idea is to calculate the stress in an inclined plane of a bar under tension for which you need the surface. I have no idea how this surface is derived, though. In the attached file, you can see what I mean. For a rectangular cross-section, it's...

I read in couple of articles, like this one: https://link.springer.com/content/pdf/10.1007/BF00324203.pdf that regions of fused silica surface can be ablated by laser... I have two questions: 1- Why does the ablation occur? 2- does the ablation happens when the laser waist point is under the...

View from above of fused silica chip. In the image is fused silica and the black line is burned fused silica caused by laser, when I cast droplet that contains molecules, never mind which kind of aggregation I tried different kinds of molecules, the aggregation is more preferably on the burned...

Purcell says that taking the surface integral of the magnetic field ##\textbf{B}## over the surfaces ##S_{1}, S_{2}, S_{3},...## below is a good way of finding the average of the volume integral of ##\textbf{B}## in the neighborhood of these surfaces. More specifically, he says in page...

I found out the time when rotation ceases to be 4 ##v_0## /5*mew*g, where mew=coefficent of friction of surface but I am unable to plot the graph post that time

Gauss' law dictates that charge will only appear on the outer surface of a conductor. But if there's charge in a conducting cavity, the inner surface of the conductor will accumulate induced charge. So what's outer or inner should be redefined?

1. Can I use the surface charge equation: $$Q = \frac{Vk\epsilon_0A}{d}$$ Where V = Voltage, k = dielectric constant, ϵ0 = permittivity of free space , A = Area of plate and d = distance between plates. For a conductive plate within an electric field? My thinking is that if the plate is...

Hi all, I'm trying to understand when surface terms go to zero. I'm not really getting a connection other than many textbooks just saying surface terms go to zero. I have added a photo of Liboff's Kinetic Theory page 3 on Lagrange's equations. Before equation 1.7, he says the surface terms go...

I’m currently studying Fluid Mechanics, during an analysis I came across this We now consider an example that combines centrifugal force and gravity: a liquid in a drum (centrifuge) rotates with constant angular velocity ##\omega## about a vertical axis. The centrifugal force per unit of...

hello there, I am wondering if my attempt at a solution for this particular problem correct?? I mean I know that the blocks won't move and the total friction force is 38.95N (at least lesser than that, since that is the maximum static friction). I saw someone attempted the solution but it is...

Some of us may use coffee coaster for our drinks. I was always wondering about that phenomenon and failed to find something on the net yet.

This video has been popping up in my feeds over the last day or so, as I'm sure others here have also seen it by now. Looks like it has been taken with one of these super zoom cameras. After watching it carefully several times, it doesn't appear to be done with creative video editing, which I...

why isn't Surface tension reliant on the composion of the atm? For an instance; If you place a glass of water in a room with regular atmosphere or you place it in a room filled with other gasses. The coefficient of surface tension of the fluid will change? Maybe? why isn't viscoty of a fluid...

If i want to calculate the volume of a cone i can integrate infinitesimal disks on the height h of the cone. I was told that if i want to calculate the surface of the cone, this approximation is not correct and i have to take the slanting into account, this means that instead of...

Hi, I've been stuck for a long time with this exercise. I am not able to calculate the potential vector, since I do not know very well how to pose the itegral, or how to decompose the disk to facilitate the resolution of the problem. I know that because the potential vector must be parallel to...

I can find the area of the triangles but can't solve the squares for some reason

I was thinking of a standard, high school level discussion of the displacement current. The need for introducing this quantity is demonstrated by considering a circuit with a charging capacitor, and (for the sake of simplicity) a circular loop whose axis is along the (straight) wire carrying the...

Hello, I'm looking for the governing equations for the laser radiation on a surface. I understand there are several types and methods. I was wondering if there is an equation to show all the parameters in calculating a surface temperature after laser radiation for a specific time. Some of the...

I do not understand how can I parameterize the surface and area and line differentials.

Is there an equation that a surface dweller could developedto globally describe his or her surface? Let us say a sphere? If we determine that curvature is everywhere constant what would be an equation that would describe that surface ? (simply that curvature is everywhere constant?) And if...

I know that I am supposed to use the equation I wrote, but how do I find the maximum force of static friction and coeffcient of static friction if none of them are given beforehand? I can't have to unknowns in an equation. We then did the same thing, the only difference was then to measure the...

V at surface = k Q / r = 9 x 109 x (1 x 109 x (-1.6 x 10-19) / (1 x 10-2) = - 144 V V at a point far away = 0 V From the sentence "electric potential difference between the surface of this sphere and a point far away" means that the question asks about V at surface minus V at far away so the...

Given ##F (x, y, z) = (0, z, y)## and the surface ## \Sigma = (x,y,z)∈R^3 : x=2 y^2 z^2, 0≤y≤2, 0≤z≤1## i have parametrised as follows ##\begin{cases} x=2u^2v^2\\ y=u\\ z=v\\ \end{cases}## now I find the normal vector in the following way ##\begin{vmatrix} i & j & k \\ \frac {\partial x}...

Hi all, I know qualitatively that charges tend to concentrate on sharp edges of conducting surfaces. I have tried searching online for a mathematical treatment of such a phenomenon, but I cannot find anything that's quite rigorous. I'd appreciate it if someone could guide me towards such...

Full article: https://www.aura-astronomy.org/news/nsfs-newest-solar-telescope-produces-first-images/

Is there any mistake in the following answer because I m always getting the result of 10362 mm 2 ? A piece of steel tube, has an external diameter of 140mm and an internal diameter of 80mm. What is the area of the surface at one end of the steel? Answer (13424 mm2)

From what I read on the internet I found that increase in surface area that is in contact is offset by the reduction in pressure. What exactly does it mean? This is what I understood from the it (but my understanding might be absurd :-p): does reduction in pressure mean that the "hills" or...

I tried to solve this question using conservation of momentum. The momentum of the system is mc(vc)=mcvc'+mbvf'. But after that I have no idea I want to use the conservation of kinetic energy but the question doesn't say it's elastic collision, I need to find the velocity of the mb after the...

I'd like to understand the movement of a particle along the surface of a three dimensional graph. For example, if there is a flat two dimensional plane (z=2 for all x and y), and a unit vector describes its initial direction of movement (<sqrt(2)/2i+sqrt(2)/2j> for example), then the vector...

Hello, I am trying to solve a problem at work that at first I thought was easy but has proven trickier than I originally thought: If I have a strip of material traveling in a straight line and it is tangent to a roll turning below it, the roll would need to turn at the surface speed of the...

Hello; What equations on mechanics can I use or study in order to measure the maximum force in Newtons the surface of the metal Steel box can hold. Details: Watch the image below, we have a metal box made of let's say steel, this box have a shape of rectangle of a thickness of for example 1cm...

Why does the force due to surface tension act parallel to the surface here? I know that surface tension is a result of absence of cohesive force above the surface and thus the water molecules below pulls the surface down and keeps it like a stretched membrane. If the surface is pressed as...

Note that the solution is 5625 V/m in z direction which is found easier using Gauss' law, but I want to find the same result using Coulombs law for confirmation. Lets give the radius 0.04 the variable a = 0.04m. ##\rho## is the charge distribution distributed evenly on the surface of the...

To find ##\sigma_b## I can use a Gaussian surface of a cylinder of length ##L## and radius ##c>r>b##. Since that is inside of the outer conductor, I know the electric field is zero, so I have from Gauss' Law, $$0=2 \pi L\left(b\sigma_b+a\sigma\right)$$ and easily solve for ##\sigma_b##. For...

When calculating force due to surface tension across a hemispherical drop, we look at only the circumference and multiply it by the value of surface tension. When we know that it is the surface tension which is responsible for the curved surface of the liquid drop, why don't we calculate the...