Solid Definition and 1000 Threads

Homework Statement Hello, I am to find the volume of the solid given by x2 + (y-1)2=1 rotated about the y-axis. I may use either shells or cylindrical method. I attempted shell method, but am just learning this, still foggy and this is the one question that isn't coming out right. Homework...

Forgive me for asking this question if the answer is obvious. The truth is I have a BENG in electrical engineering and want to know the differences between the two. From an engineer's perspective its about knowing what you can do with the devices in a useful way and design, analyze and build the...

Hi All, I'm trying to create something which has a solid, cylindrical, non-reflective core (assume the core is made out of a black rubber similar to that of a car tyre for instance and 20m in length, but only 1cm in diameter), which has a translucent or transparent plastic layer (or several...

I am interested in ultrafast optical spectroscopy of solid state materials. The unique measurements and especially the process of developing new measurement tools for the optical measurement of quantities that are hard to measure in other ways, and the learning of transferrable skills, make this...

Homework Statement The electric field at a distance of 0.143m from the surface of a solid insulating sphere with radius 0.381m is 1630N/C . a) Assuming the sphere's charge is uniformly distributed, what is the charge density inside it? b) Calculate the electric field inside the sphere...

How long before our magnetic field disappeared and how long after that would we be dead due to radiation?

Homework Statement Use the shell method to find the volume of the solid generated by revolving the region bounded by the line y=2x+15 and the parabola y=x2 about the following lines: a) The line x=5 b) The line x= -3 c) The x-axis d) The line y=25 Note: leave answer in terms...

When light passes in glass, water etc then velocity is reduced and direction changes HOW?

I am an undergrad and for the most part I am looking for a good physics class to take. I am considering taking solid state physics at the level of Kittel as its one of the only physics classes offered at the undergrad level this semester that I haven't taken. I haven't taken quantum mechanics...

For some systems, discrete intermediate compounds rather than solid solutions may be found on the phase diagram, and these compounds have distinct chemical formulas; for metal–metal systems, they are called intermetallic compounds. e.g. Mg2Pb has 33 at% Pb For binary isomorphous system like...

If so, what about smells coming from solid matter, like wood?

I want to know the derivation of solid angle. I have found on net. But the derivation is to long, is there any short method?

Hi Everyone, I was curious as to what the most current model in solid state physics is. I've studied the Einstein and Debye Models in Stat Mech, as well as free electron and tight binding models in an intro solid state class, but these models are rather old(which does not imply they are...

Looks like it is time for round two... So for any of you who were following my other post (https://www.physicsforums.com/showthread.php?t=762560) about whether or not to glue my model or make a solid piece for a modal analysis, you know that I was having a lot of trouble deciding. It turns out...

Learing about matter and what it is composed of, I'm spending a lot of time trying to wrap my brain around the idea that most of our mass is empty space, that the mass of our atoms is calculated and expressed in energy. How is this possible? Are the recreations moving so fast they almost create...

Homework Statement "A solid sphere rolls down an incline plane without slipping. If the center of mass of the sphere has a linear acceleration of 1.21 m/s2, what is the angle of the incline to the horizontal?" Homework Equations a = g * sin(θ) The Attempt at a Solution I got home...

I m considering to design a solid axle ATV for rear wheel drive without differential...so I want to know about what design considerations I have to consider while its designing.(like track width...suspension linkage position)

I am performing Modal analysis on a fairly simple structure (a square aluminum rod with some pillars attached to the top of it) and need to get some basic modal analysis results. Making a solid aluminum piece would be rather expensive and time consuming to design and then mill out, so the...

Homework Statement A solid disk is spinning around it center with an angular velocity of 35.0 rad/s. The disk has a mass of 3.6kg and a radius of .50m. You drop a thin ring with the same radius and a mass on the disk along the same center of rotation. What is the angular velocity of the...

I am somewhat confused about the connection between divergence and solid angle for a beam. I know individually what each term means... but I'm confused as to how (or even if) one can calculate the solid angle of a beam, given the divergence. I have some notes from a previous lecture series I...

Hi, I am taking (ordinary) differential equations as a summer course and we are studying from a horrid textbook, in my opinion. Just curious if anyone might be able to suggest what is considered to be the "standard" introductory text on ODE. While I'm certainly interested in PDE, I don't...

Okay, so, we have y=2/x, y=0, x=1, x=3 and it's rotating around y=-1 As I understand it... This means (2/x +1)^2-(0+1)^2 (4/x^2 + 4/x) The integral of that is -4/x + 4ln(x) Am I right so far? Plug in the 3, and then the 1 -4/3 + 4ln(3) - -4+4ln(1) Then the result of that is multiplied...

Homework Statement A solid cylinder of radius R is spun and then placed on an incline having coefficient of friction μ=tanθ (θ is the angle of the incline). The solid cylinder continues to spin without falling for time: (A)Rωo/3gsinθ (B)Rωo/2gsinθ (C)Rωo/gsinθ (D)2Rωo/gsinθ The Attempt at a...

If it’s true that every atom has negatively charged electrons on its outer shells, and if it’s true that all matter is made of such electrons, be it our finger or a mountain or a planet, (meaning that all ‘things’ are negatively charged) and if it’s further true that what appears is not...

1.find tthe volume solid generated by revolving the region bounded y=sqrt x and the ;lines y=1, x=4 about the line y=1 2. using simpson rule witj n=4 to aproximate int from 0 to 1 1 over 1-x power 2 dx

Homework Statement The titleHomework Equations NahThe Attempt at a Solution It has no free moving ions or electrons Then, my teacher saw the electrons and gave 0 marks to the question(It was on the test paper) He said that if he didn't see electrons there, he would have given a mark. Why? I...

I was not sure exactly where to put this but it involves images so I thought it was no too inappropriate here. I was reading the Feynman Lectures Vol.1 and he says that Helium, although not solid at absolute zero normally, can be so in high pressures. I then googled this for images but none...

Homework Statement A small solid sphere of mass M0, of radius R0, and of uniform density ρ0 is placed in a large bowl containing water. It floats and the level of the water in the dish is L. Given the information below, determine the possible effects on the water level L, (R-Rises, F-Falls...

Hi, I am studying fluid mechanics and I am trying to get to grips with slip and no-slip boundaries. I know that: Slip ---> Occurs when fluid is inviscid so no viscous stress at boundary. No-slip ---> Viscous effects mean the the tangential velocity must be zero, relative to the boundary...

So, the igbt bridge system i have going is a 600 volt 300 amp full bridge of cm300 igbt's and i was wondering if a .660uf tank capacitor is too big for my system. The mmc is made out of 2000 volt 1uf capacitors, 2 strings of 3 in series. Thank you.

Hey guys, I would just like some confirmation that I got this question correct. Homework Statement For the stress block shown in Figure 3a, using the stress equations; a) Calculate the stresses sigmax' sigmay' and taux'y' on a stress block rotated 15° clockwise from the x-y axes...

Homework Statement Hey guys, I have a test coming up soon, and our lecturer gave us a sample test. I am working through it, but we have not been given any answers to confirm if what we are doing is correct. The Question: "For the simply supported beam (with upstand) shown in...

hello everyone, i am looking for a comprehensive link for the topic above as i want to do some research on various applications of x-rays in solid state physics. its a personal research but i have some materials but i still feel i need a whole lot more. Any form of help would be appreciated...

I am doing a project in Chemistry and I need to use Hess' Law to cancel two equations and if in one equation the NH4NO3 is solid and in the second one the NH4NO3 is aqueous. The equations are: 1: NH4NO3 (s) + HCl (aq) --> HNO3 (aq) + NH4Cl (aq) 2: NH4OH (s) + HNO3 (aq) --> H2O (l) + NH4NO3...

A solid has a circular base of radius 3. If every plane cross section perpendicular to the x-axis is an equilateral triangle, then it's volume is I keep on getting 18 root 3. But the answer is 36 root 3. Could I get some help? Thanks.

Homework Statement Use a double integral to find the volume of the indicated solid. Homework Equations The Attempt at a Solution I can't find what I did wrong, it seems like a simple problem... $$\int_0^2 \int_0^x (4-y^{2})dydx=\int_0^2 4x-\frac{x^{3}}{3}dx$$...

I bought a Stainless Steel soap bar and it works, it just does. It was from China and hollow inside and I would like to know if that's either a cost cutting measure or how the bar works? What would happen if it were solid? Another thing would be if it had a magnetic core, or made from a metal...

Homework Statement The figure shows a 200 g uniform rod pivoted at one end. The other end is attached to a horizontal spring. The spring is neither stretched nor compressed when the rod hangs straight down. What is the rod’s oscillation period? You can assume that the rod’s angle from vertical...

Homework Statement In Kittel's 'Introduction to solid state physics' (8th ed.), on page 167, it says "The wave functions at the Brillouin zone boundary ##k=\pi/a## are ##\sqrt{2} cos (\pi x/a)## and ##\sqrt{2} sin(\pi x/a)##, normalized over unit length of line." Here I cannot understand...

Homework Statement How to derive equation (22) on page 31 of Kittel's Intro to Solid State Physics 8th edition. The equation is: 2\vec{k}\cdot\vec{G}+G^2=0 Homework Equations The diffraction condition is given by \Delta\vec{k}=\vec{G} which from what I can surmise is the starting...

Homework Statement I'll provide picture for clearer understanding. The solid cylinder of mass ##m## and radius ##r## revolves about its geometric axis at an angular rate ##p## rad/s. Simultaneously, the bracket and shaft revolve about x-axis at the rate ##\omega## rad/s. Determine the angular...

Is it possible to create a solid whose sides are all quadrilaterals, and whose vertices are all bringing together four edges? I've been playing around in autocad and haven't been able to come up with a way to do this. I'm trying to make a checkerboard type of solid where no touching faces have...

Homework Statement 5. The nuclei of atoms in a certain crystalline solid have spin one. Each nucleus can be in anyone of three quantum states labeled by the quantum number m, where m = −1,0,1. This quant number measures the projection of the nuclear spin along a crystal axis of the solid. Due...

Homework Statement A horizontal 845.0 N merry-go-round with a radius of 4.3 m is started from rest by a constant horizontal force of 74.0 N applied tangentially to the merry-go-round. Find the kinetic energy of the merry-go-round after 2.2 s. Assume it is a solid cylinder. The...

I'm having some trouble with this problem: Find the volume of the solid of revolution, or state that it does not exist. The region bounded by f(x)= 6(4-x)^(-1/3) and the x-axis on the interval [0,4) is revolved avout the y-axis. How would I be able to tell whether to use the shell, disk, or...

Find the volume of the solid of revolution, or state that it does not exist. The region bounded by f(x)= the square root of ((x+3)/(x^3)) and the x-axis on the interval [1,infinity) is revolved around the x-axis. I tried using the disk method: pi* (sqrt(((x+3)/(x^3)))^2 Then I think I have to...

Homework Statement Silver has a density of 10.5E3 kg/m3 and a resistivity of 1.6E-8 Ω*m at room temperature. On the basis of the classical free electron gas model, and assuming that each silver atom contributes one electron to the electron gas, calculate the average time, Tau, between...

Why do atoms just have a general vicinity of which they rest in a solid?

Homework Statement Find the volume of the solid generated by rotating the region enclosed by y=\frac{1}{1+x^2} , x=-1,x=1 and y=0 about the line y=2 Homework Equations pi(outer radius)^2-pi(inner radius)^2 The Attempt at a Solution Since i am rotating around a horizontal line i figured...

hi guys! i was wondering if the solid magnet part of a brushed dc motor needs to be strong in order to make a strong motor? I'm designing a motor from scratch and wondering if i should use an existing ferrite magnet that is somewhat strong or should I design a electromagnet that is stronger...