Normal Definition and 1000 Threads

1. The homogeneous square body is positioned as shown. If the coefficient of static friction at B is 0.40, determine the critical value of the angle theta below which slipping will occur. Neglect friction at A. The image: 2. NA is the Normal force at A, which is perpindicular to the...

Hi all, I need help regarding the following expression: E(x1|X>K) where: x1 is a one dimension normal rv X is multivariate normal rv with n components: x1, x2,..., x_n K is a n dimension constant vector with n components: k1,k2,...,k_n X>K <==> x1>k1,x2>k2,...,x_n>k_n I know there is...

Homework Statement A tennis player slices the ball to spin and deviate from its normal parabolic path. What is an explanation for this phenomenon? I am having trouble visualizing the phenomena that is occurring with the slice and as well as the explanation give by the book. How is the...

let x a point on complex manifold X, z_j a coordinate system at x , E a holomorphic bundle and let h_α be a holomorphic frame of E. After replacing h_α by suitable linear combinations with constant coefficients we may assume that h_ α is an orthonormal basis of E_{x}. Then an inner product <h_α...

Here is an example in which the normal force would not be counted as an action-reaction pair. A 100g block is sitting at rest on a horizontal table. According to Newton's third law, which of the following indicates the correct action-reaction pair of the two forces? So I was stuck between C. The...

Homework Statement The 2000 mm long composite bar shown in Fig. 1 consists of an aluminum bar having a modulus of elasticity EAl = 70 GPa and length LAl = 500 mm, which is securely fastened to a steel bar having modulus of elasticity ESt = 210 GPa and length LSt = 1500 mm. After the force P...

Hi there, I have performed a multiple regression analysis and I am checking the assumptions. The normal probability plot is not exactly a straight line, but is it okay? If you were looking at the plot would you be satisfied hat the normality assumption is valid...

Hi all, I've been working on a little side project, but I've hit a road block on the maths for this one. Basically if you imagine a sealed pack of 10 cards, there is a 20% chance that the pack contains one foil (more valuable) card. The mass distribution of the foil cards are (heavier and)...

Hello, My question stems from a research project of mine involving taking the normal modes of clusters of molecules from a potential. I was curious of the interpretation that can be made of normal mode vectors at a non-equilibrium structure, i.e something following a MD trajectory beginning at...

Hello, My question stems from a research project of mine involving taking the normal modes of clusters of molecules from a potential. I was curious of the interpretation that can be made of normal mode vectors at a non-equilibrium structure, i.e something following a MD trajectory beginning at...

I'm programming a process that runs in iterations with a probability of stopping at every iteration. As it gets closer to the desired run-time, this probability should increase so that if the process is run many times over, the runtimes will form a normal distribution, with most of them having...

Hi, I have a rather basic question: most 'cosmic rays' have an energy of about 109 eV, but there are also 'Ultra-high-energy cosmic rays' with an energy of around 1019 eV to 1020 eV, so I was wondering if they couldn't be the result of collisions of two 'normal' cosmic rays that hit each...

Homework Statement I've attached the question. Homework Equations μ=np and σ=√(np(1-p)) Im using the normal distribution function on my calculator to avoid using z tables The Attempt at a Solution The mean I calculated it to be 160/4 = 40. standard deviation...

Hi, I am doing research and I am stuck at this point I need help to convolute iid non central chi-square with normal distribution.

Hello everyone. I've been looking into joining my university's honors calculus course. I graduated high school with Calc 1, and Calc 2 completed, but I didn't do too well because, I didn't apply myself as much as I should have (senioritis). I received a 3.0 in Calc 1, and a 2.4 in Calc 2. Do you...

Homework Statement Given position vectors: OA ( i + 2j - k) ; OB ( -i + 2j +3k); OC ( 2i + j + 4k) Given that OA is perpendicular to OB. The Question : Show that OA is normal to the plane OBC. Homework Equations r . n = d To find the normal of the plane OBC, I used n = BO x...

Homework Statement If we are simply standing on the ground will our normal force be always equal to our weight besides when we are jumping or when we land on the ground from a fall? When we are in an elevator, will the normal downwards force on the floor be of our weight (cancelling out our...

For a normal distribution with E[x]=0 and Var(X)=1, how do we determine the Z-value of a particular percentage ? i.e. if the percentage is 5%, how do we know that Z(5%)= 1.645 ? is there a calculation involved or do we get it from observing the x-axis of the normal distribution ?

Homework Statement Find the flux of the following fields: F_1 = xi + yj F_2 = -yi + xj across the following curve: The circle r(t) = (cost) i + (sint) j t is from [0,2pi] Homework Equations Flux = ∫F dot n ds = ∫M dy - N dx The Attempt at a Solution For F_1 I got: M = x =...

Hello. I am new to electronics and physics. Since injuring my back at work, I now have a lot of time on my hands to learn about the things that facinate me. So please forgive me for any wrong terminology or spelling and grammar mistakes. I have recently made a small jacobs ladder using a lm555...

Hi, I am trying to find a resource that can explain how σ and ∏ lines obtain their polarizations. I have not found resource that actually show the calculation or solid explanation that show this.The references are usually state that σ and ∏ have circular polarization and linear polarization...

Other than the obvious case of the (real or perceived) pressure of a full bladder eventually becoming unbearable, under what conditions do healthy people, i.e. those who do not ordinarily suffer from incontinence, lose bladder control? I know of two - extreme fear and choking/strangling. In the...

Suppose we have a normal distribution and a sample of n values from the normal distribution. To estimate the variance we can use the standard sample variance formula ( average squared distance from the mean divided by either n ( biased estimator ) or n-1 ( unbiased estimator ) ). There is...

help me find this normal vector! Homework Statement Find a normal vector n and the equation of the tangent plane to the surface S at the point x0 S: z=ln(x2+3y2) x0=(2,-1,ln7) Homework Equations The Attempt at a Solution ok so I have this general formula from the textbook. z=...

Hi all, I'm a little confused about Bloch modes vs. waveguide modes of a single waveguide and was wanting some pointers. I read that Bloch modes are results of the wavefunction of a particle (usually, an electron) placed in a periodic potential. In the case where we have an array of cylinder...

Let X be standard normal and Y uniform [0,1] find the distribution of Z=X/Y. i think i managed to deal with this problem up to the integral stage: P(X/Y< t ) = P(X<Y*t ) thought of : 1. F_{z}(t) = \int^{1}_{0}\int^{yt}_{0}f(x,y)dxdy 2. F_{z}(t) = \int^{yt}_{0}f(x)dx maybe is neither one of...

Homework Statement Let X1,X2 be a random sample of size 2, from a normal distribution with mean μ and σ2=1. Let T=t(X1,X2)=X1+X2 be the estimator of μ and l(t;μ)=t-μ be the loss function. Compute risk function R(μ). Homework Equations R(μ)=∫∫(l(t;μ))∏f(xi;μ)dxi The Attempt at a...

Hey guys, i'm building an apparatus with a sliding pin containing a spring and a ball. I want to lock in two different positions so I've rounded two slots in the housings. I would like to know what is the equation two find the normal force of the spring on the ball depending on the displacement...

Homework Statement r(t)=cos(t)i+sin(t)j+sin(2t)k Find the curvature κ, the unit tangent vector T, the principal normal vector N and the binormal vector B at t=0. Find the tangential and normal components of the acceleration at t=∏/4 Homework Equations T(t)=r'(t)/|r'(t)| N(t)=T'(t)/|T't|...

Hello, all. I'm wondering about matrix-variate normal distributions. I know they normally assume an n x p random matrix, X, and associated row and column covariance matrices Omega and Sigma, but I'm wondering how the probability density function changes if X is comprised of a square...

Proposition: If every element of G/H has finite order, and every element of H has finite order, then every element of G has finite order. Proof: Let G be a group with normal subgroup H. Suppose that every element of G/H has finite order and that every element of H has finite order. We wish to...

Ignoring the fact that it is redundant at times, is this proof correct? Also, is there a way to show that same result using the fact that K is closed with respect to conjugates rather than the fact that for all a in G, aK=Ka. Thank you! :) Proposition: If H and K are subgroups of G...

why is hydrogen the only element in the periodic table that lacks a neutron?

cylinder of mass m and radius r rests on two supports of same height. one is fixed other slides with velocity v.determine normal force N by the cylinder on stationary support at the moment when distance between the point of contacts A and B of cylinder and support) is r√2assuming supports were...

Homework Statement The line that is normal to the curve x2+2xy-3y2=0 at (5,5) intersects the curve at what other point? 2. The attempt at a solution I differentiated the equation, found the slope of the curve at that point, and I then found the equations for the tangent line and normal...

Homework Statement Given X,Y RV both have normal distribution with: μ_{x}=6,μ_{y}=4,σ_{x}=1,σ_{y}=5,ρ=0.1 a. are X,Y independent? b. find P(X≤5) c. find P(Y≤5|X=5) 2. The attempt at a solutiona. no -> ρ=0.1 -> cov(X,Y)≠0 b. define Z=\frac{X-6}{1} ; Z~N(0,1) so P(X≤5) = P(Z≤-1) = \Phi(-1)...

I've been reading that the diagonalizable matrices are normal, that is, they commute with their adjoint: ##M^*M=MM^*##, where ##M^*## is the conjugate transpose of ##M##. So a matrix is diagonalizable if and only if it is normal, see: http://en.wikipedia.org/wiki/Normal_matrix But from...

Suppose you have a single variable differentiable function r: R -> R restricted to an interval, like [0,1] for simplicity, if you want. Consider the surface of revolution obtained by rotating the graph of r around the x axis. How do I find the NORMAL VECTOR to the surface at each of its points...

I took a LA course in the spring, and was interested by the least squares method for building models. I decided to practice this concept by attempting to build a model that would predict ticket sales for the Mega Millions lottery given the jackpot amount. I have 249 data pairs of jackpot and...

I want to calculate \int_a^b \frac{1}{\sqrt{2 \pi \sigma^2}} e^{(-(x-\mu)/\sigma^2)} log_2 (1 + e^{-x}) dx

Homework Statement Let U be a domain in \mathbb{C} with z_0 \in U. Let \mathcal{F} be the family of analytic functions f in U such that f(z_0) = -1 and f(U) \cap \mathbb{Q}_{\geq 0} = \emptyset, where \mathbb{Q}_{\geq0} denotes the set of non-negative rational numbers. Is \mathcal{F} a normal...

I've been interested in this function Youtube offers on videos ever since I first used it a few months ago. It's amazing. Some videos are just way too long. The speakers will have something very informative to say, but they'll just ramble and/or speak very slowly. For some reason, Youtube only...

This is the my homework.Who can solve this for me ? i upload my solutions and the problem .Thanks.

Hi guys ^^ I am still at A level physics, so don't flame me for my lack of knowledge Now i have been taught that for ex: We have a block of wood named A at rest on a perfectly smooth surface. If we analyse a free body diagram, we have a weight mg downwards acting on the block and a normal...

Given a bivariate gaussian distribution, I'm attempting to find the probability p for which the ellipse of all points (x,y) for which P(X = x, Y= y) = p contains a given % of the samples drawn from the distribution. I want the 2d equivalent for the 1 dimensional case: given a normal...

1) If X~N(μ,σ2, find the value of c in terms of σ such that P(μ-c ≤ X ≤ μ + c) = 0.95 Attempt: Ok so I have a feeling I will eventually need to reference a standard normal table, but I tried to standardize the rv first: P (-1 ≤ (X-μ)/c ≤ 1 ) = 0.95 Now here's where I'm stuck, what...

Homework Statement Hi I am having tough time figuring out how to determine normal stresses σx, σy, σz using the flexure formula. All that confuses me is which moment to take for which σ. My for σx or Mz for σx and so on.. I will post an example question. In the question below, find the...

Homework Statement Let Z follow a standard normal distribution. Compute E(Z^3) and E(Z^4) Homework Equations I know that mu is 0 and sigma is 1. And f(z) = e^(-z^2/2)/sqrt(2pi) The Attempt at a Solution I tried to take the integral of ∫Z^3 * f(z) from the integral from -∞ to ∞...

I'm having trouble finding the equation normal to the plane for part (ii). The vector equation I got for part (i) is r=(1/2,1,2/3) + t(3/2,2,-2/3). How do you deduce the normal vector from this? The answer is the vector (9,12,-4). I've tried anything but don't know where they got this result...

Stokes' theorem uses the curl of a vector field dotted by the normal vector of a surface...but what happens when you use a larger or smaller normal vector? You get a different answer but the theorem doesn't specify to use the unit normal vector. So which normal is the correct one to use...