Surface Definition and 1000 Threads

The Theia hypothesis is the current leading hypothesis to explain how our moon was created. Both Earth's mantle and the moon's surface have indistinguishable oxygen isotope ratios, which leaves the earth–moon system as more similar in O isotopes than any other two bodies in the solar system...

Homework Statement Homework EquationsThe Attempt at a Solution Since the wheel is rolling , vcm=ωr , acm = αr The wheel is in pure rotation about the point O where it touches the surface . The point P is a distance 4/3 from the bottom point . Angular acceleration of the point = 3 rad/s2...

Homework Statement I have a project to research the effect of surface roughness on wing performance. I found mostly that roughness leads to increased drag on a wing, however came across a website that briefly spoke about how recently researchers have observed how carefully selected roughness...

A torus with major radius, ##R##, and minor radius, ##r##, has a total surface area given by ##4\pi^2 Rr##. If one slices the torus on its midline (i.e. at a line on a poloidal angle of ##-\pi/2## and ##\pi/2##), I was told the inner half of the torus has a smaller surface area than the outer...

first thing first i want you to excuse me for my Grammar or spelling cause i am really bad at both !we know that what gives the thing gravity is the mass the mass warp the space-time fabric but Jupiter has a low mass than earth how does it have all this amount of gravity or the warping in the...

2 SEM images of gemstones: emerald and ruby (Electron Miscroscope with Secondary Electron detector, (which "takes picture" of surface layer (~0.5 um) both the elemental composition and relief)). Dendrites - it is clear (not me, but in general), what creates other patterns? * trace elements? -...

Homework Statement Homework EquationsThe Attempt at a Solution Using Stefan Boltzmann Law , The power emitted per unit area by the small sphere is P/A = eσT4 . The power absorbed per unit area by the surface is given as P/A = eσT04 . How should I use the distance between the two surfaces ?

Hi, I am conducting the experiments with the electroless nickel plating of the brass (CZ121). I have read a lot of the literature about this process prior to the lab tests. All brass surface cleaning procedures that I have came across involve the electroless cleaning (I understand why)...

Why do charges outside the surface contribute 0 net flux? The book I'm reading says it's because the flux entering the surface cancels out with the flux exiting the surface. But that means E dot Area must be exactly the same magnitude when entering and exiting to cancel out. But we know E-field...

Homework Statement Consider an infinitely long one dimensional conducting wire with a homeogenous charge density ##\lambda##, running along the central axis of an infinitely long cyclindrical glass casing of radius b (glass is a dielectric material). Calculate: a) The displacement vector...

Homework Statement With regards to a one dimensional conducting wire with a homogeneous charge density λ surrounded by a cylindrical glass dielectric of radius R, find: (a). The displacement vector inside the dielectric (b). The surface bound charges on the surface of the dielectric Sorry...

I run a vacuum distillation unit that is used to distill ethylene glycol. The old glycol is subjected to 25Hg of vacuum at a temp of 275 degrees F. There are burner tubes submerged in the glycol to heat it up. The vessel has a diameter of 36 inches and is 124 inches long. We fill the vessel...

Homework Statement I am currently trying to do a literature survey on my project task 'effect of wing surface roughness on wing performance'. I have been struggling to find many research papers that are of a similar experiment to mine, however i have come across many that investigate the effect...

Homework Statement Suppose we have a Electic field, E (vector) = kr2r(vector). Find the total charge contained in the sphere of radius R centered in the origin. solution- here E can also be written as kr3r∧, where r∧ is the unit vector this is the given question , so obiously the best way to...

Hello, I am given 200,000 surface points in terms of x,y and z coordinates which is supposed to represent a circular paraboloid antenna reflector surface and another 200,000 points when the antenna surface is subjected to wind loads and gravity. I am supposed to find the surface RMS error of...

Homework Statement A 10 g bullet is fired at 200 m/s into a 1 kg block after which they slide together 2 m on a horizontal surface. Determine the coefficient of kinetic friction between the block and surface. Homework Equations ##M_AV_{Ai} + M_BV_{Bi} = 0## ##WNC = ΔE## The Attempt at a...

A friend mine of gave me a problem : Calculate the Emf b/w the axis and surface of a long current carrying wire of radius ##r## and current density ##J##. I am not able to understand why there would be a potential difference between the axis and surface but i think that either of these could...

I'm a bit confused as to how to imagine a negative sensible heat flux near the Earth's surface. Negative means that sensible heat is moving towards the surface. My book states that that would mainly occur at nighttime. During day there is a positive sensible heat flux and sensible heat moves...

The problem is, find the surface area of the volume of revolution generated by rotating the curve y=e2x between x=0 and x=2 about the x-axis. Here's what I have so far... SA=∫y√(1+y2)dx =∫e2x√(1+4e4x)dx and from here I'm not really sure what to do. Any help would be appreciated.

Hello, I'm accidentaly confused when my mate ask me "what actually happen when touch a surface of mass, ie: table, chair, etc). Which we are know that 99,999999999% of atom is space" Is we really touch atom? Help me please

Given is the function f: R2 -> R, with f(x,y)=x2+y2-6xy+8y. The level surface f(x,y)=1 contains infinitely much points (x,y) where x and y are integer. How can I prove this? I see that it is true with some examples, but how can I prove this. Do I need to use the gradient? Or tangent planes? Or...

Homework Statement A uniform charge density of 700 nC/m3 is distributed throughout a spherical volume of radius 6.00 cm. Consider a cubical Gaussian surface with its center at the center of the sphere. [reference picture] What is the electric flux through this cubical surface if its edge...

Okay... I have a question about "effect of surface area on loudness".I am going to upload a diagram along this post.It shows two scenarios. The "red thing" is a barrier, which allows absolutely no air contact between the speaker and the listener. So the only way the sound can travel outside is...

Hello How the surface tension is measured for molten metals? I have heard about the sessile drop, but it seems to be a very inaccurate method... Thank you for your time. Regards.

What is the surface area ("surface volume") of a 3-sphere having a radius of 2 Planck lengths? Is the product of the Planck's constant, Einstein's proportionality constant and Planck time also equal to this volume? Does this equivalence signify anything? What does it signify?

Hi, I've been trying to figure out how to get Cauchy Stress Tensor components (~9) from a surface force for a while now. My background in this subject is not too deep, but I'm trying to build a renderer simulation in my free time. I can get surface traction from a Stress Tensor: t =...

Hello everyone, I just had a question for you all. I am trying to use a laser to scan a particular surface. What software or data retrieval tool would I need in order to view the surface in question after scanning it with a laser? Also, what wavelength and wattage would you suggest for getting...

I want to demonstrate to flat earthers that water does indeed stick to a ball. If we want to do a scale model of the earth, at which radius will gravity overcome the surface tension?

This may sounds like a stupid question but... If you were to use a subsea lifting bag filled with O2 it would rise to the surface. Would the same happen with CO2? I assume the density of CO2 is different so the amount required would be more or less than O2, but it is still less dense than...

Homework Statement Cylinder : x^2 + y^2 = 1 Plane that intersects above cylinder: y + z = 2 What is the surface area of the sides of this cylinder? Homework Equations dS= R1 d@ dz @ is from 0 to 2 pi z is from 0 to 2 - y dS=(Zx^2 + Zy^2 + 1)^.5 dA Where Z = 2 - yThe Attempt at a Solution I...

Let's say we have a rolling without slipping (e.g. mentioned ball) on flat surface. Does it mean that the ball will accelerate to infinity ?

Hi. I'm trying to self-study vector calculus and I have to admit I struggle with it. As regards finding normals to a surface I know 2 ways - one involves writing the surface equation as f(x.y.z) = 0 and taking the gradient. The other method involves writing the surface in terms of 2 parameters...

Head psa(suction surface pressure) = 2.31xP/specific gravity This is one of the factors to calc NPSH. Shows how much head is pushing liquid through the pump. What does the specific gravity have to do with surface pressure of a liquid before it goes into the pump? Isn't it just involving the...

For my research I am trying to study the temperature change of a warm fluid (air) flowing over a cold surface, but I have not studied fluid mechanics. Does anyone know of an equation that can be used to analyze this problem? To give some reference, the hot air is 49 Celsius and the cold air is...

I'm confused as to how this expression E= (δ/εo) can't be used to calculate the electric field of a perfectly flat part of a surface even farther from just above the surface.If you just extend the same cylindrical Gaussian surface used for this proof, wouldn't the field stay the same no matter...

For example, the curvature due to a mass; does that curvature continue passing from within to outside the mass's light cone? If so, is the mass subject to the external curvature? If not, does the curvature have a discontinuity at the light cone surface?

Homework Statement A city with 30,000 residents lies next a lake which is their only source of water. The average family of four in this city uses 1100 liters of water per day. Neglecting rain and evaporation, how much depth would the lake lose per year if it covered 40 square kilometers...

Homework Statement A small sphere of radius R held against the inner surface of a smooth spherical shell of radius 6R as shown in figure. The masses of the shell and small sphere are 4m and m respectively. This arrangement is placed on a smooth horizontal table. The small sphere is now...

From my drawings it seems to be half of hemisphere. Am I right? How can I solve this task? Determine the flux of the vector field $$ f=(x,(z+y)e^x,-xz^2)^T$$ through the surface $Q(u,w)$, which is defined in the follwoing way: 1) the two boundaries are given by $$\delta...

Homework Statement In a configuration having axial symmetry about the z axis, a line current I flows in the −z direction along the z axis. This current is returned at the radii a and b, where there are uniform surface current densities Kza and Kzb , respectively. The current density is zero in...

Homework Statement Hey all, another problem. There is a 1 meter wooden panel that is on a frictionless surface. A puck is placed on one end of the panel and is pushed towards the other side. The mass of the panel is 10 times that of the puck. Also, there is a friction coefficient of uk=0.15...

Homework Statement Homework EquationsThe Attempt at a Solution If I consider an arc shaped element of the liquid, then the physical forces acting on it are 4 different tensions , normal force and gravitational force on it. Two of the tensions would be acting along tangential direction...

I googled a lot on proof of Gauss theorem and nearly every other proof (on web and so on books) state that solid angle of closed surface is 4pi but I can't find the proof of this nowhere ! I tried setting up the integral but don't know how to proceed furthur : Ω=∫(cosθ/r^2)*dA Also The one...

What is actually the unit normal vector of a surface? Is it this? Or this one? I see that those are opposite in direction. But, I want the correct one, which means that it should point outward. So, which one is correct?

Hello, Using surface energy dependence on surface orientation it is possible to predict equilibrium crystal shape by applying Wulff construction. But I faced the problem when the surface energy depends not only on the surface orientation but also on the surface depth or surface termination and...

I don't understand, when calculating the force to change the surface area of the film, how the length obtained in the diagram below is "l" (lowercase L). I understand that there are two surfaces to overcome, hence the factor of 2, but why is the length perpedicular to the force used and not...

Homework Statement A cone has half angle θ0 and lateral surface area S0 in the frame in which the cone is at rest. If someone moves at relative speed β=v/c along the cones symmetry axis, what surface area will they see for the cone? Homework Equations I believe the lateral surface area of a...

so df/dy' is yy'/ √(1+y'^2) then we are supposed to do y' . [ yy'/ √(1+y'^2) ] - y√(1+y'^2) how does this bring equation 2 in the image ?

At one point I read there was the concern that a black hole could lose bits of information. Then a theory arose that showed that all the bits in a black hole were to be found on the surface of the black hole. Thus if there were let's say 1000 particles in a black hole each of which could be...

Homework Statement There are n isolated condutoctors in space: Sum of charge of all conductors is positive. Show that surface density is postivie everywhere on at least one of conductors Homework Equations Using induction The Attempt at a Solution -It's clear that if we have one conductor...