Normal Definition and 1000 Threads

Hello everyone, I have a question. I'm not sure if it is trivial. Does anyone have ideas of finding a matrix ##A\in M_n(\mathbb{C})##, where ##A## is normal but not self-adjoint, that is, ##A^*A=AA^*## but ##A\neq A^*?##

I know that orbital angular momentum is quantized. If the potential energy is developed because of the external magnetic field applying a torque on the magnetic dipole, then from the dot product of the dipole moment and magnetic field we have a cosine term, shouldn't this give rise to all the...

Homework Statement Draw the combinatorial circuit corresponding to the disjunctive normal form. Homework Equations DNF of f(x,y,z)=xyz+Not(xy)z The Attempt at a Solution f(x,y,z)=xyz+not(xy)z =z(xy+not(xy)) Wouldn't the xy and not xy cancel out? That's my current problem with this...

Homework Statement A jet of water , 50mm diameter , with a velocity of 18m/s , strikes a flat plate inclined at 25 degree to the axis of jet as shown in figure, Determine the normal force , P exerted on the plate when plate is stationary . Homework EquationsThe Attempt at a Solution in the...

I've calculated the joint distribution, XY_PDF(x,y) of random variables X and Y (both coming from a distribution N(n) = C*e^(-K*n^2)). I use XY_PDF(x,y) to calculate the joint distribution AR_PDF(a,r) of the random variables A (angle) and R (radius), with the PDF method and the Jacobian. Since...

Homework Statement A boy slides on a sled on the curved track sketched (black line). (Treat the boy and sled as a particle.) His mass plus that of the sled is m = 41 kg. Friction and air resistance are negligible (I want a sled like that!). His initial speed is v0 = 1.3 m.s–1. The height h =...

Homework Statement the figure showed a jet of water , with velocity 50m/s strikes the flat plate , which is inclined 30 degree to the jet . Find the force normal to the surface of jet. Homework EquationsThe Attempt at a Solution my question is the flat plate is 30 degree to the horizontal...

Hi, I have this math problem where I need to find the scalar component of acceleration at a given time under certain conditions. Usually these problems aren't bad for me, but this one has left me scratching my head. Its giving me ||a|| = 4 and (aT)(T) = 5i +5j -k I have the formula aN =...

Hi, I'm not sure about the the normal vector N on a complex function z(x,t) = A e^{i(\omega t + \alpha x)} My approach is that (\overline{z} beeing the conjugate of z): \Re{(\mathbf{N})} = \frac{1}{\sqrt{\frac{1}{4}(\partial x + \overline{\partial x} )^2 + \frac{1}{4}(\partial z +...

Homework Statement A student sits a test and is told that the marks follow a normal distribution with mean 100. The student receives a mark of 124 and is told that he is at the 68th percentile. Calculate the variance of the distribution. Homework Equations...

Hey! :o Let $G$ be a non-abelian finite group with center $Z>1$. I want to show that if $G/Z$ is a $p$-group, for some prime $p$, then $G$ contains a normal $p$-Sylow subgroup and $p\mid |Z|$. We have that $$|G/Z|=p^n, n\geq 1\Rightarrow \frac{|G|}{|Z|}=p^n\Rightarrow |G|=p^n|Z|$$ That means...

Homework Statement Homework Equations relevant equations are provided with each question below The Attempt at a Solution please check my solutions to ensure they are correct. thanks. a) [/B] b) Calculate net force: Fnet = FA + Ff + Fg Fnet = (1.20 x 104 N [up]) + (1.40 x 103 N [down])...

Hey! :o I want to find a normal series of $D_4$ and all the composition series for $D_4$. I have done the following: $D_4=\langle a , s\mid s^4=1=a^2, asa=s^{-1}\rangle$ A subgroup of $D_4$ is $\langle s\rangle=\{s, s^2, s^3, s^4=1\}$, that is normal in $D_4$, since $[D_4:\langle...

If I have a system where the following is found to describe the motion of three particles: The normal modes of the system are given by the following eigenvectors: $$(1,0,-1), (1,1,1), (1,-2,1)$$ How can I find the corresponding eigenfrequencies? It should be simple... What am I missing?

Why is normal force always perpendicular to the surface? I understand that normal force is the upward reaction force by a surface due to an external action force pushing the surface. Then, if I apply an extermal force on a non inclined surface at an angle, let's say 30 degrees, shouldn't the...

Homework Statement A 22-gram mass is released from rest at position A on a stationary frictionless surface whose shape is that of a quarter circle of radius R = 0.66 m. (b) Determine the magnitude of the normal force that acts on the mass when it is at position B (it is at position B when the...

Homework Statement A multiple choice test consists of a series of questions, each with four possible answers. How many questions are needed in order to be 99% confident that a student who guesses blindly at each question scores no more than 35% on the test? Homework Equations So I know that...

Homework Statement A 60 kg skier is beginning her descent down a 26 degree slope. The frictional force between the skis and the snow is 4 N a) What is the gravitational force the skier exerts on the slope? b) What is the normal force the slope exerts back on the skier? Homework EquationsThe...

\begin{eqnarray*} &&\mathbb{E}\left( 1_{\left\{ X_{1}+X_{2}>\rho \right\} }X_{1}X_{2}\right) \\ &&\mathbb{E}\left( 1_{\left\{ X_{1}+X_{2}>\rho \right\} }X_{1}^{2}\right) \end{eqnarray*} where ##X_1## and ##X_2## are independent normal variables. I am wondering whether there exist closed-form...

Homework Statement The ellipse is given as (x^2/a^2) + (y^2/b^2)=1 I´m meant to calculate a tangential vector, a normal vector and find an equation for the tangent using a random point (x0,y0). I´m meant to do this in 2 ways: firstly by using the parametrization x(t)=a*cos(t) and...

Hello! As far as I know any subgroup can, in principle, be used to divide group into bundle of cosets. Then any group element belongs to one of the cosets (or to the subgroup itself). And such division still is not qualified as a quotient. Yes, the bundle of cosets in this case will be...

For the following question I am given a plane: x + 2y + 3z = 12. I want to find the equation of a line normal to the plane and going through the point (4,6,8). I am trying to use the formula N . (r - r0) = 0 however seem to be getting the incorrect answer :(

Hey! :o I want to find all the normal subgroups of $D_n$. We have that $$D_n=\langle a, s \mid a^2=1=s^n, asa=s^{-1}\rangle$$ We have that $K$ is a normal subgroup of $D_n$ iff $$gkg^{-1}\in K, \forall g\in D_n \text{ and } \forall k\in K$$ Could you give me some hints how we could find...

Hey! :o I want to show that $N\{1, (12)(34), (13)(24), (14)(23)\}$ is a normal subgroup of $S_4$ that is contained in $A_4$ and that satisfies $S_4/N\cong S_3$ and $A_4/N\cong Z_3$. Let $\sigma\in S_4$. We have the following: $$\sigma 1 \sigma^{-1}=\sigma (1) \\ \sigma (1 2)(3 4)...

Hey! :o I want to show that if $H$ is a cylic normal subgroup of a group $G$, then each subgroup of $H$ is a normal subgroup of $G$. I have done the following: Since $H$ is a normal subgroup of $G$, we have that $$ghg^{-1}=h\in H, \ \forall g \in G \text{ and } \forall h\in H \tag 1$$...

So say I have a truncated normal. That is, N(mu,sigma) that is from 0 to infinity only. I need to find a Gamma such that a constant C*Gamma(A,B) is always above N(mu, sigma). How would I go about finding such a A, B that would work given fixed mu and sigma?

1. The problem statement Hi, I just have a quick question on how to find the normal force in this picture on mass 2, http://postimg.org/image/w9sr29ab3/ , the half circle. Its a double pendulum with no friction. Can I assume that the normal force is in that position all the time as the half...

Find the standard score for a the data value 9 from a normal distribution which has a mean of 16.8 and a standard deviation of 2.3

So I have been asking my self these questions lately. I know it is some basics of physics and I should probably know the answer.. Why do we feel weightlessness when we hit the acceleration of gravity (9.8) exactly? Probably so that the surface that we are standing on doesn't need to produce any...

Homework Statement <I will attach a diagram below> In terms of m, g and r. FInd the normal force at the top of the loop. Homework Equations ∑F = Fc = FN+Fg ∴ Fc=FN+Fg ∴FN = Fc - Fg ∴ N=mV2/r - mg The Attempt at a Solution Fc=mV2/r - mg and V2=ra and a=g ∴C=mrg/r ∴C = mg ∴mg-mg=N ∴ N=0 N. BUT...

[Note: Thread moved by moderator] Hi! so I have a question I am unable to do and I've been trying it for 3 hours. The question had 2 parts, i figured out part a but cannot figure out part b. A) A 0.006kg ball is dropped from a height of 4.0m above the floor. Neglecting air resistance...

Homework Statement why the normal acceleration is 6 rads^-1 ? It's not stated in the question , right? Can someone explain more about normal acceleration? i couldn't understand it . I only know that when the rod is rotated , it has tangential acceleration Homework EquationsThe Attempt at a...

Homework Statement Let $$ \Phi(x)=\int_{-\infty}^{x} \frac{1} { \sqrt{2\pi} } e^{-y^2 /2} dy $$ and $$ \phi(x)=\Phi^\prime(x)=\frac{1} { \sqrt{2\pi} } e^{-x^2 /2} $$ be the standard normal (zero - mean and unit variance) cummulative probability distribution function and the standard normal...

If a car us on a frictionless banked track what causes the normal reaction force to be greater than the weight force? My understanding from what I've read is that the vertical component of the reaction force cancels the weight force which makes sense as the object doesn't leave the ground. And...

This isn't actually a problem. It is a doubt which I have about wedges according to Newton's Laws Consider a friction less wedge, of mass 'M', inclined at angle θ, placed on a smooth horizontal surface, on which a block of mass 'm' is placed. The block exerts some normal force perpendicular to...

so I got my sphere, centered at (1,-2,0) with radius 3 how do I put normal vectors/arrows onto my sphere's surface? I tried quiver3(x,y,z)

Hi Community, I have this question. I start by creating the derivative, $$\d{}{x}(x^2-xy+y^2) = \d{}{x}(3) $$ and solve for $$\d{}{x}(3) $$ = 0 (Derivative of a constant is alway 0) I understand how to solve the derivative of $$\d{}{x}(x^2-xy+y^2)$$ and get $$2x-y$$ In the worked...

Please can you help me with this question. A surface h in the three dimensions is given by the equation z=g(x,y) Find the unit normal at any point h in two separate ways: a)By identifying h with an equipotential for some scalar field φ to be determined and computing ∇φ. b)By expressing the...

Homework Statement Hey guys, I have been making progress in classical mechanics but I'm having a tough time figuring out how to solve for the normal frequencies for this set of equations of motion: http://imgur.com/nQKPNsu In order to account for the mass gravity term here the book suggests...

Homework Statement There are ##N = 10000## clients of an insurance company. One-half of them will file claims with probability ##p_1 = .05##, another half of them will file claims with probability ##p_2 = .03##. Each claim is worth ##$1000##. Find the Value-at-Risk at the level α = 0.99, that...

Gravity does act on a satellite so why is normal force 0 for an object placed inside it?

Homework Statement An ice cube is placed on top of an overturned spherical bowl of radius r, as indicated in the figure. If the ice cube slides downward from rest at the top of the bowl, at what angle θdoes it separate from the bowl? In other words, at what angle does the normal force between...

Homework Statement An engineer is measuring a quantity q. It is assumed that there is a random error in each measurement, so the engineer will take n measurements and reports the average of the measurements as the estimated value of q. Specifically, if Yi is the value that is obtained in the...

Homework Statement Here's the problem. I was able to find the a_n and b_n values, my question is mainly on part (c), how do I find which modes are missing? The function is odd, so even modes should disappear, but cos(n*pi) doesn't disappear, it's either +1 or -1. I'd greatly appreciate any...

why does the normal on a mass have different values at pole and equator

Hi Folks, I got stuck towards the end where it ask to derive the unit normal (eqn 3.2.29 I don't know how they arrived at n_x. I have looked at trig identities...and I have assumed the following n_x=\frac{N_x}{|N_x|} I don't see the (r+p) term anywhere in neither the top nor bottom. PS: I...

Hi Folks, I got stuck towards the end where it ask to derive the unit normal. I don't know how they arrived at n_x. I have looked at trig identities... n_x=\frac{N_x}{|N_x|}= 1) I don't see the (r+p) term anywhere in neither the top nor bottom. 2) Is the bottom just based on simple trig...

Homework Statement [/B] Homework EquationsThe Attempt at a Solution I'm not really sure how to attempt this question tbh. In order for the lamps to have normal brightness I think the circuit must be parallel. I also think maybe for A there can only be one lamp per branch because there's...

Homework Statement I am supposed to find the tangent and normal unit vector to r(t)=<2sint,5t,cost>.Homework Equations . The Attempt at a Solution r1(t)=<2cost,5,-sint> which is a tangent vector to the curve, and then to make it a unit vector I would multiply by 1/(sqrt(4cos^2t+25+sin^2t)...

Not a textbook/homework problem so I'm not using the format (hopefully that's ok). Can someone offer an explanation of normal modes and how to calculate the degrees of freedom in a system of coupled oscillators? From what I've seen the degrees of freedom seems to be equal to the number of...