Normal Definition and 1000 Threads

Suppose I have already found the surface normal vectors to a set of points (x,y), how do I compute the surface height z(x,y)? Basically what I have are the normal vectors at each point (x,y) on a square grid. Then I calculate the vectors u = (x+1,y,z(x+1,y)) - (x,y,z(x,y)) and v =...

I recently learned that with (local) gauge invariance, functional quantization needs to factor out volume factor(Faddeev-Popov procedure). Why does this has to be done?Just to remove infinity? As far as I am concerned, ##\phi^4## theory contains invariance(for example ##\phi\to\phi\cdot e^{i...

Homework Statement I've not been able to do this question for years so I'd really appreciate some help. Light is normaly incident from a medium 1 with impedance Z1 through a layer of medium 2 of thickness L and impedance Z2 into medium 3 of impedance Z3. Obtain an expression for the total...

Homework Statement Due to the pollution from the industry around an apple farm, the apples grown there may be contaminated by heavy metals. It is believed that the amount of heavy metals in an apple of the farm follows the Normal distribution. N(16,16) which has a mean μ = 16 units and σ = √16...

I took a practice Ap Physics test today and did well, but there was a basic problem that hung me up: there are two boxes on the ground on top of each other. the top box's mass is 2m, and the bottom's is 1m. question: just looking at the bottoms box's normal force, does it equal the 2m box on...

Does anyone know the proof of joint moment generating functions for bivariate normal distributions? M_x,y (s,t)= E(e^(xs+yt))

The way I understand it, they both have rectangular forms which are easy for addition/subtraction. Now I realize that the polar form of a complex vector can be simplified into an exponential, which is ideal for multiplication/division. But this is what confuses me; vectors don't multiply/divide...

I can't convince myself whether the following functional derivative is trivial or not: ##\frac \delta {\delta \psi(x)} \big[ \partial_x \psi(x)\big],## where ##\partial_x## is a standard derivative with respect to ##x##. One could argue that ## \partial_x \psi(x) = \int dx' [\partial_{x'}...

Homework Statement The system is conformed by two blocks with masses m (on the left) and M (on the right), and two springs on the left/right has the spring constant of k. The middle spring has a spring constant of 4k. Friction and air resistance can be ignored. All springs are massless. Find...

Homework Statement [/B] This problem is from Jon Rogawski's Calculus-Early Transcendentals At a certain moment, a moving particle has velocity v={2,2,-1} and a={0,4,3}. Find T, N and the decomposition of a into tangential and normal components.Homework Equations ANYTHING IN [ ] REPRESENTS A...

why does light refract toward the normal when passing through glass?

I was just curious as why, when drawing a free-body diagram of a board about a pivot with weight on either side of the pivot, we do not consider the corresponding normal forces to those weights(using torque considerations). This question was already asked in another post but was asked a little...

Ok I know this is simple resolving but I'm a bit confused. If we resolve forces in the vertical y direction (as in the attached image), we obtain Rcos(theta)-W=0 and hence Rcos(theta) = W meaning R = W/cos(theta) [where theta = 18 degrees] However, if we resolve forces along the direction of...

Homework Statement "There is a pulley with 2 blocks on the table.Force "F" is acting on it ,as it can be seen here A=10 kg and B=20 kg F=294 N Now,my exact problem is my teacher says "there is no contact force between A and the table.." Why block A is not pushing against table while block B...

Homework Statement During an extreme stunt, a 45 kg cheerleader stands on the shoulders of a 55 kg cheerleader, while riding in a transparent elevator with an upward acceleration of 2 m/s2. Find the normal force between the cheerleaders and between the elevator and the bottom cheerleader...

Are all quantum states represented by normal vectors?

I have a small problem with this question. In this problem, the cone exerts a normal force. This force, should be perpendicular to the inside surface of the cone. In equating the vertical forces, I need the vertical component of this normal force. I would draw this force perpendicular to the...

Homework Statement Suppose that diastolic blood pressures (DBPs) for men aged 35-44 are normally distributed with a mean of 80 (mm Hg) and a standard deviation of 10. What's the probability that in a random sample of 5 subjects, 4 or more have DBPs more than 90? Homework EquationsThe Attempt...

Homework Statement I made a two-dimensional array program, but now I need some help to alter the program in the print zone. The Attempt at a Solution import sys students = [] grades = [] while True: student = input ("Enter a name: ").replace(" ","") if...

My teacher says In case (A) there would be normal contact force between the blocks.But in case (B)There will not be any normal contact force between the blocks. I am really not getting this.I think The normal force is the support force exerted upon an object that is in contact with another...

Homework Statement Problem: In an acid-base titration, a base or acid is gradually added to the other until they have completely neutralized each other. Let X and Y denote the milliliters of acid and base needed for equivalence, respectively. Assume X and Y have a bivariate normal...

Homework Statement A horizontal uniform bar of mass 260 kg and length L = 3.0 m is placed on two supports, labeled A and B, located as shown in the diagram. A block of mass 60 kg is placed on the right end of the bar. Find the normal forces FA and FB exerted on the bar by the supports. Enter...

Hi comunity! I need to make a code o a normal distribution of velocities, starting whit a random secuence uniformly distributed between [0,1]. I am using FNT95, with Plato. I want to obtain a ''for'' bucle with I=1,N for the velocities. It is importan for the distribution to have sigma defined...

I heated epsom salts in the oven at 450F to make some make-shift desiccants and it went from white (some even clearish) crystals to solid white powder (caked together) with the edges turning a light shade of brown and a deeper brown at the 4 corners of the pan. Can this damage the MgSO4, is...

Hello So I've done some calculations, I'd like to see if my stuff is right. Thanks :) Please view attached http://i.imgur.com/AfMZyr0.jpg area = (pi)(9^2) = 254.46 Cos53.13=15/CG CG=25kN Normal stress = 25000/254.46 =98.25

Homework Statement Homework EquationsThe Attempt at a Solution I can understand it intuitively, but can't prove mathematically...Can you help me??

Given five data points (minimum, 25th percentile, 50th percentile, 75th percentile, maximum), do I have enough information to be able to construct what a normal (Gaussian) distribution would look like? I have no data on any other statistical information (population size, mean, median, mode...

Homework Statement Find P(X>130) where P(X > 130) = 1 − Φ( (130 − µ)/σ ) Homework Equations Φ is the normal distribution density function: http://en.wikipedia.org/wiki/Normal_distribution The Attempt at a Solution This is pretty simple to use in R if one knew how to. I get a ghastly incorrect...

Homework Statement Homework EquationsThe Attempt at a Solution I know that the solution involves setting the normal force to zero and equating the radial component of gravity to centripetal force. But why is it not possible for the normal force to decrease at a sufficiently low rate such...

Homework Statement I have to prove that ## \int e^{\frac{x^2}{-2}}dx ## from +∞ to -∞ = ##\sqrt{2\pi} ## Homework Equations N/A The Attempt at a Solution My GSI went from 1) ## \int e^{\frac{x^2}{-2}}dx ## from +∞ to -∞ = ##\sqrt{2\pi} ## to 2) ## (\int e^{\frac{x^2}{-2}}dx)(\int...

Homework Statement Find a normal subgroup H of Zmn of order m where m and n are positive integers. Show that H is isomorphic to Zm. Homework EquationsThe Attempt at a Solution I am honestly not even sure where to start. My initial thoughts were if Zmn was isomorphic to Zm x Zn then I could...

Suppose we have a block on an inclined plane. If we choose the x-y axis to be parallel and perpendicular to the inclined plane, then we have Fy = N - mgcos30 = 0 But if we choose our trivial x-y coordinate system, where y is parallel to the force of gravity, then we get: Fy = Ncos30 - mg =...

Hi, everyone. I am learning fluid mechanics. One book says that for a infinitesimal fluid cell, surface force includes 1) the pressure, which is imposed by the outside fluids surrounding the concerned fluid cell 2) the shear and normal stress, which result in shear deformation and volume...

Alright, so I know there will be a normal force pointing perpendicular to the surface and gravitational force, right? Gravitational force = mg But since normal force acts in "opposite direction to the gravitational force". Wouldn't normal force then cancel out the gravitational force? If it's...

Homework Statement A room has two opposing walls which are tiled. The remaining walls, floors, and ceiling are lined with sound-absorbent material. The lowest frequency for which the room is acoustically resonant is 50Hz. (a) Complex noise occurs in the room which excites only the lowest two...

Homework Statement You purchase a chainsaw, and can buy one of two types of batteries to power it, namely Duxcell and Infinitycell. Batteries of each type have lifetimes before recharge that can be assumed independent and Normally distributed. The mean and standard deviation of the lifetimes...

Hello, I have two jobs,Normal distribution with mean of 4.5 minutes and standard deviation of 1.5 minutes for type 1 and uniformly distributed between 1 and 3 minutes for type 2

I'm attempting to work out when to use the different formulas and how everything fits together, can you confirm if the following is correct? 1) If we had the problem: There are 250 dogs at a dog show who weigh an average of 12 pounds, with a standard deviation of 8 pounds. If 1 dog is chosen at...

I'd like to ask a couple of questions. As a solid object gets bigger, the molecular orbital (combinations of all single atom orbitals) has greater size too? For a one inch square object (of closely packed molecules like crystals), what is its molecular orbital size compared to a one foot square...

Homework Statement In an amusement park ride called The Roundup, passengers stand inside a 19.0m -diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane, as shown in the figure 1. Suppose the ring rotates once every 5.50s . If a rider's mass is...

In the picture, at point 2 (the bottom of the ramp) the normal force of the object has a greater magnitude than weight. I understand that the normal force has to be greater than the weight since the acceleration points towards the center of the circle and the net force is in the same direction...

Homework Statement [/B] Find the coordinates of the point P on the surface of the paraboloid z=6x2+6y2-(35/6) where the normal line to the surface passes through the point (25/6, (25√22)/6, -4). Note that a graphing calculator may be used to solve the resulting cubic equation. Homework...

Let X be random variable and X~N(u,σ^2) Thus, normal distribution of x is f(x) = (1/σ*sqrt(2π))(e^(-(x-u)^2)/(2σ^2))) If we want to standardize x, we let z=(x-u)/σ Then the normal distribution of z becomes z(x) = (1/σ*sqrt(2π))(e^(-(x^2)/(2)) and we usually write Z~N(0,1) But as you can see...

It is a fact that all inertial observers would measure the same area normal to a beam of light rays in relativity. You can prove this by considering the displacement vector connecting a light ray to its neighbouring light rays. But I wondered if there were some intuitive explanation of why this...

Homework Statement [/B] A horizontal force, ##F##, is applied to a cylinder of mass ##M## and radius ##R## (the line of action of ##F## goes through the center) in order for the cylinder to climb over a step of height ##R/2##. 1) Find the torque around ##A## and find force ##F## as a...

Homework Statement http://www.sumoware.com/images/temp/xzmbharheaqshjjf.png A homogeneous stick with mass M is placed in a well with smooth surface (see picture). θ is the angle between the stick and the floor. Determine the force the well gives to the stick. Homework Equations ΣF = 0 Στ =...

A bead of mass m is threaded on a metal hoop of radius R. There is a coefficient of kinetic friction µk between the bead and the hoop. It is given a push to start it sliding around the hoop with initial speed v0 . The hoop is located on the space station, so you can ignore gravity Find the...

Homework Statement [/B] A belt moves over three pulleys at a constant speed v0 [ft/s]. Knowing that the normal component of the acceleration of the portion of the belt in contact with pulley B is aB,n=90 [ft/s2 ]. Determine: (a) speed of the belt, v0 [ft/s], and (b) normal component of the...

1. Problem: Consider the composed system of two particles of spin ##s=1## where their angular momenta is ##l=0##. What values can the total spin take if they identical? What changes when they are distinguishable? The Attempt at a Solution : The problem I have here is incorporating the fact...

Homework Statement The walls are smooth, calculate the reactions. the cylinder weighs 100[N]. Now the 600 wall is rough with a friction coefficient 0.4. what are the reactions Homework Equations Friction: F=μN The Attempt at a Solution I made the first step and it was good: N1=287.9, N2=253.2...