Static Definition and 1000 Threads

I've asked a similar question before in some way or another, I'm still troubled by it. Technically there is no such thing as a static electric field: Take for instance a parallel plate capacitor Argument #1: Electrons are always moving inside the conductor, they have a finite thermal energy...

Hi, I have a question about the static gauge in string theory, in which one sets \tau = X^0 I understand that in the usual approach for strings in a flat target space, after the gauge fixing of the worldsheet metric gamma, \gamma_{\alpha\beta} = \eta_{\alpha\beta} one...

Homework Statement What is the upward force required to make pipe start to move? There is a fixed point and a 36 inch shaft. The force would be applied 36 inches away to the point. The load is 1700lbs. The end point only needs to come up enough so that the static friction of the pipe is...

Anybody know where I can find data on normal street-tire friction coefficients on dry asphalt? I'd like both the static, and the kinetic coefficients. If not, can somebody give me a range of reasonable values? While I'm at it... What about racing slicks on asphalt? I found one source...

hi, this is the first time i am using this website and have found it very informative ao far.. so i am working on this assignment and have got stuck on this question. the query is .. why does static pressure vary on the surface of vehicles and how does it affect the aerodynamic...

Static moment VS Moment of inertia -- what's the difference? What's the difference between moment of inertia and static moment? How does it differ in calculations?

I can use Noether's theorem and the homogeneity of time to derive the conservation of energy for a static E field, but can I also use the homogeneity of space to derive the conservation of momentum?

Why doesn't static electricity cause ionic bonding,since some atoms become positively charged and others are negatively charged ?

Hi, I'm new here. This question may already have an answer but I didn't find it. Sorry if there's already one. It's a static version of the twin paradox, without travel and without twins. We have 2 circles C and C' that are superposed. C is fixed, with time t and co-ordinate x along the circle...

Homework Statement http://img849.imageshack.us/img849/3716/staticeqpulley.jpg Hopefully the image showed up. If not, here's the link: [PLAIN]http://img707.imageshack.us/img707/3716/staticeqpulley.jpg" Sorry for the low quality pictures. Hopefully it will do though. The question is: Relate...

Can someone give me an example of a case where kinetic force would be greater than static force? Thanks.

Homework Statement i tried to compute the electrostatic field of a charged ring at a point not in the center i have problem with transforming from xy to polar system what do you think about this try? Homework Equations The Attempt at a Solution

i want to design a machine which is capable of applying all three types of loads that is axial, bending and torsion. Using this application of static loads , I want to measure the stress concentration factor.

Scenario: If a human body is fully charged with positive electrons (protons/lack of electrons) and comes in contact with a pool of positive electrons such as a charged plate, the charge stays the same in the human body and the plate. Now if the human comes in contact with a source of negative...

I want to simulate this type of situation but for simplicity I'm implementing it in 2d at first.. by setting the initial velocity 0 in parallel to B. Homework Statement mass of particle is given assume anything charge magnitude of B initial velocity Homework Equations The...

Homework Statement We have triangle with sides d1,d2,l and angle \alpha between d1 and d2. Assume small change \Delta\alpha of \alpha. Homework Equations Then we can write for \Deltal equation \Deltal=(d1*d2)/(l) * sin\alpha\Delta\alpha. How can I prove that? The Attempt at a...

Homework Statement Mountaineers often use a rope to lower themselves down the face of a cliff (this is called rappelling). They do this with their body nearly horizontal and their feet pushing against the cliff (the figure ). Suppose that an 76.2 kg climber, who is 1.88 m tall and has a center...

Homework Statement A solid metal sphere of radius 'a' is concentric with a hollow metal sphere of inner radius '2a'. The space between the spheres is filled with a dielectric material of relative permittivity 'ε' carrying a uniform static charge density 'ρ0'. The charge density is zero...

Why can't a static spacetime have an ergosphere? An ergoregion is just a region outside the event horizon where k can become negative (k being a Killing vector field that is timelike near infinity). Both stationary and static spacetimes have such a KVF so surely static spacetimes could also...

Can I express "stationary spacetime" and "static spacetime" in this way? Can I express "stationary spacetime" and "static spacetime" in this way? stationary spacetime: if we arrange a set of observers locating in any places, then each of them should observe nothing change at the place where...

I have some problems using this definition, maybe because it's not valid in every coordinate system: T^{\mu\nu} = (\epsilon + p) \frac{dx^{\mu}}{ds} \frac{dx^{\nu}}{ds} -p g^{\mu\nu} since in cylindrical coordinates x^0 =t \qquad x^1 =\rho \qquad x^2 = \phi \qquad x^3 =z using weyl metric...

Hey, I have a question in how one can calculate the static dielectric constant, f, of NaCl. NaCl has density of 2170kg/m3, a lattice constant a= 5.6 A and a Young's modulus Y = 40GPa. the optical dielctric costant is 2.34. I couldn't find any formulas which connect these values together. We...

Hi, I would like to model static buildup and discharge. It will be appreciated if someone can point to me a direction. Thanks! Pei-Ying

Homework Statement During an earthquake, a floor oscillates horizontally in approximately simple harmonic motion. Assume it oscillates at a single frequency with a period of 0.84 s. After the earthquake, you are in charge of examining the video of the floor motion and discover that a box on...

Homework Statement In the figure below the charge in the middle is Q = -4.6nC. For what charge q1 will charge q2 be in static equilibrium? q1-----10cm------Q------10cm------q2 I know that the answer is supposed to be 18nC. Homework Equations F=Ke lq1llq2l/r2 The Attempt at a Solution...

Homework Statement A car is traveling at 50 mi / hr on a horizontal highway a. If the coefficient of static friction between the road and tires on a rainy day is 0.100, what is the minimum distance in which the car will stop? b. What is the stopping distance when the surface is dry and μs =...

Homework Statement My problem is getting the SOLVE() function to work correctly. I have used it plenty of times in the past, but when I put in these 4 equations to solve simultaneously, it gives me the wrong answers. My Professor said that TI-89's sometimes have problems when having to solve...

A crate is in a pickup truck traveling horizontally at 15.0 m/s. The trucks apply the brakes for 28.7 m while stopping with uniform acceleration. What is the coefficient of static friction between the crate and the truck bed if the crate does not slide? I know how to solve for the...

Homework Statement http://img848.imageshack.us/img848/5884/screenshot20110425at121.png Uploaded with ImageShack.us Homework Equations Sum Horizontal forces = 0 Sum vertical forces = 0 Sum moments = 0 Sum Horizontal Forces=0 The Attempt at a Solution Dx-Ax+Bx+Cx=0 Dx-Ax+Bx+981 Sum Vertical...

Homework Statement It's not possible for me to solve this problem. Maybe work/energy relations is required ? Homework Equations I've ended up with polynomiums of 3. and 4. degree, trying to find the roots. But finding the...

Q: "If a curve with a radius of 85m is properly banked for a car traveling 65km/h, what must be the coefficient of static friction for a car not to skid when traveling at 95km/h?" [PLAIN]http://a4.sphotos.ak.fbcdn.net/hphotos-ak-ash4/215513_1974874979462_1470693940_32310002_1293630_n.jpg...

Hello I do not understand the answer given, i may be thinking too hard? Q: "What is the maximum acceleration a car can undergo if the coefficient of static friction between the tires and the road is 0.90?" A:"The static frictional force is the accelerating force, and so F(friction) =...

Homework Statement how can i show the universe is static and not expanding, how it really is. Homework Equations \OmegaM=... \Omega\Lambda=... The Attempt at a Solution "The expansion history of the universe depends on the amount of matter (gravity), quantified by \OmegaM...

static and total pressure ! hello :) i'm new here and it is the 1st time i post a thread here ... now please correct me if I'm wrong... 1-static pressure is equal to the total pressure if the gas is static (V=0) 2- total pressure is always equal or bigger than the static pressure 3-as...

I'm doing a lab for my technical dynamics class and that lab is to determine the coefficient of static friction between a metal washer and both metal and rubber surfaces. I did the experiment using 3 washers set at different distances from the center of the turntable as instructed, and...

A static magnetic field in a homogeneous, linear, medium with permeability μ0 is given in cartesian coordinates by: B(x, y, z) = B0 tanh (x/L) z where L is a constant. a) Sketch Bz as a function of x/L. b) What current density, j(x,y,z) produced this magnetic field? c) Sketch any...

Homework Statement I have been given two forces and have to calculate the magnitude and direction of the third force that will result in equilibrium. The two forces I have been given are: F1 = 2.156N at 48 degrees F2 = 4.508N at 203 degreesHomework Equations I used both the cosine law (c^2...

Homework Statement A bridge truss extends x = 214 m across a river (Fig. P12.68) where θ = 35°. The structure is free to slide horizontally to permit thermal expansion. The structural components are connected by pin joints, and the masses of the bars are small compared with the mass of a 1270...

I was left bewildered by a question our teacher left us to think about over the next week. He asked us how we can demonstrate static friction doing positive work, using a pen and a sheet of paper. Can anyone tell me how I can do this, and why this is so?

Homework Statement A nonuniform fire escape ladder is 6.0 long when extended to the icy alley below. It is held at the top by a frictionless pivot, and there is negligible frictional force from the icy surface at the bottom. The ladder weighs 250 , and its center of gravity is 2.0 along the...

Homework Statement a) If the co efficent of static friction between a table and a uniform massive rope is Us, what fraction of the rope can hang over the edge of the table without the rope sliding? Homework Equations F=mg The Attempt at a Solution The largest fraction of the...

I think I remember reading somewhere that almost every moment of our lives we are surrounded by thousands of volts of ambient static electricity caused by the movement of air and clouds, it's just that we don't notice it. I may have mixed up my information so I'm just asking for clarification...

Homework Statement A car is traveling at 30m/s around a bend of radius 70m. What coefficient of static friction between the tires and the road is required to ensure the car will not slip? Homework Equations The Attempt at a Solution I know that the centripetal acceleration is...

Homework Statement A 5.0 kg mass is held against a wall with which it has a coefficient of static friction of 0.85. What is the minimum horizontal force required to hold the mass against the wall ? The teacher said answer is 58 N .. i can't get to that answer.. Homework Equations...

Homework Statement The uniform rod in the figure is supported by two strings. The string attached to the wall is horizontal, and the string attached to the ceiling makes an angle of ϕ with respect to the vertical. The rod itself is tilted from the vertical by an angle θ. If ϕ = 29.9°...

http://www.nuenergy.org/pdf/static-electricity-converter.pdf

Sorry this isn't for a particular question, just wondering if anyone knows how to determine degree of static indeterminacy (or degrees of freedom) in an arbritary frame? Any help greatlly appreciated thanks.

when a material becomes charged due to static electricity how come it does not stay charged or how come the atoms of the material do not become ions

When Einstein conceived GR he added the cosmological constant in an attempt to create a static universe model. The problem with this was that it was unstable. I've recently read about static spacetime (static spacetime admits a global, non-vanishing, timelike Killing vector field K which is...

Homework Statement If the coefficient of static friction between an table and a uniform massive rope is [tex]\mu[s] what fraction of the rope can hang over the edge of the table without the rope sliding? b]2. Homework Equations [/b] The Attempt at a Solution Frictional force...