Normal Definition and 1000 Threads

  1. J

    Proving N is a Normal Subgroup of G

    Homework Statement N is a normal subgroup of G if aNa^-1 is a subset of N for all elements a contained in G. Prove that in that case aNa^-1 = N. Homework Equations The Attempt at a Solution Given: N is a normal subgroup of G if aNa^-1 is a subset of N for all elements a contained...
  2. A

    MHB Equation of the Normal and Ellipses Questions

    Hey guys, I have a couple of questions about this problem set I've been working on. I'm doubting some of my answers and I'd appreciate some help. Question: For 1a, I used implicit differentiation and isolated dy/dx. This gave me the following answer: dy/dx = (-3x^2 -4y)/(4x+12y) Which I...
  3. V

    My engine oil is green color. Its normal?

    today i did a oil change on my outboard engine. i found out the oil is green, its normal? If yes, why the oil will be green color? because i fill the new oil is golden color.
  4. T

    MHB Calculation of angles in normal anatomical curved bones that are fractured.

    Hi, I am an orthopedic surgeon. Many of our long bones are anatomically curved. When they fracture they sometimes heal in a none perfect/anatomic position. How do one calculate the angle/curve or changed angle/curve of a fractured bone healed or fixed none anatomically Please see my drawn...
  5. V

    Where does the normal distribution come from?

    Okay, so I guess my first question is if the main utility of the normal distribution ##f(x)## is to provide a probability measure for any subspace of the measurable space ##(\mathbb{R},\mathcal{B})## (where ##\mathcal{B}## is the borel σ-algebra on the real numbers) by defining the measure as...
  6. E

    Normal Distribution - self study / review

    Homework Statement My source textbook is the community college / junior college (confer: undergraduate-lower division) probability and statistics textbook: An Introduction to Mathematical Statistics and Its Applications, 2nd Edition Authors: Richard J. Larsen, Morris L. Marx 1986...
  7. A

    Dynamics: Normal and Tangential projectile motion problem

    Homework Statement A canon fires a projectile at a speed of 100 m/s at angle of 20 degrees. (a) what is the radius of curvature of the projectile at its highest altitude? (b) What is the radius of curvature of the path .5 seconds after firing? Homework Equations Velocity vector = s'ur...
  8. B

    Centripetal Force, Gravity and Normal

    Homework Statement Homework Equations F_{c} = \frac{mv^{2}}{r} The Attempt at a Solution I think the normal force would be the magnitude of vector sum of centripetal force and gravitational force. So I did: N = \sqrt{(\frac{mv^{2}}{r})^{2} + (mg)^{2}} However, it isn't one...
  9. G

    What is the normal acceleration of body in non uniform circular motion

    when the body rotates with uniform motion then the normal acceleration is V^2/r. but what is the normal acceleration when the motion is in non uniform circular motion let's say when body has uniform tangential acceleration.
  10. S

    Normal Force in Circular Motion

    Hi all, For a marble in uniform circular motion within a smooth cone, what is the relationship between the normal force by the surface of the cone and the weight of the marble? My take is that the normal force forms a reaction pair with one of the resolved forces of weight. I have resolved the...
  11. T

    Engineering Statics Question Regarding Finding Normal Force

    Homework Statement http://i.imgur.com/rwbXqW8.png Homework Equations The Attempt at a Solution So I started off by analyzing the pulley, and determined that each cable carries 100N of force. After that, I drew the FBD of the beam, where there is a 100N force going downwards on the...
  12. R

    Point Normal Equation Question

    ##ax +by +cz +d = 0## is the equation of a plane orthogonal to ##(a,b,c)## but why is there a d in the equation? What does it do to the plane geometrically? http://i.imgur.com/sMiLhHc.jpg?1 I don't see how the d fits into that geometric interpretation.
  13. S

    Is It Normal to Feel Relaxed Before Multiple AP Exams?

    I am giving three AP late testing tests (Mechanics, Calculus BC, Chemistry) in the next two days. Usually, I would be in panic mode at this point of time. However, I am normal, relaxed, just finishing up stuff for the exam in a casual (but thorough manner). I went through a couple of sample...
  14. C

    Normal Distribution Porbability

    I have ##\bar{X}## ~ ##N(\mu , 9/25)## I have ##E[X] = \mu## ##Var[X] = 9/25## ##SD[X] = 3/5 = 0.6## An interval for ##\bar{X}## has been recorded: ##\bar{X} \pm 1.05##. I asked to find ##P(\bar{X} > \mu + 1.05)## I can "normalize" the distribution through: ##Z =...
  15. M

    Going back to basics: The Normal Force

    So, usually I like to give a long description of how/why I am asking such a question, but I think this time, I'll be quick and to the point. Truth is when I first came to this site, I think I started asking questions that were well beyond my current knowledge, so I would like to take the time...
  16. Z

    Loop-the-loop normal force problem. Possible textbook error?

    Homework Statement A pilot of mass m flies a jet plane on a "loop-the-loop" course by flying in a vertical circle of radius R at a constant speed v. The force that the cockpit seat exerts on the pilot at the top of the loop is (A) mg. (B) mg\left(\frac{v^{2}}{R+1}\right). (C)...
  17. Curieuse

    Normal force on block placed on incline.2 approaches different result

    Homework Statement The problem wants me to order the choice for the directions of a force F of a constant magnitude F(a,b,c,d are unit vectors along which F has to be oriented) exerted on the block placed on an incline at 30° to the horizontal based on the normal force Fn that the incline...
  18. H

    Small Sample Size - Test for Difference between Brands with Normal Distribution

    Lets say I have 8 samples (weight) of 4 ingredients in particular food by X brand and another 8 samples by Y brand. I would like to test to see if there is any difference between the two brands in terms of weight of particular ingredients. However, I am not sure what statistic test to run and I...
  19. vanceEE

    Find the Value of c for Normal Distribution of Lemon Juice Cans | Homework Help

    Homework Statement "Cans of lemon juice are supposed to contain 440 ml of juice. It is found that the actual volume of juice in a can is normally distributed with mean 445 ml and standard deviation 3.6 ml." It is found that 94% of the cans contain between 445−c ml and 445+c ml of juice. (ii)...
  20. binbagsss

    Fresnel's Equations/ Normal Incidence/ R and T coefficients.

    The question asks to use Fresnel's equations at normal incidence to find the ratio of the refractive indexes of the two materials. We are told equal energy is transmitted and reflected and that both media are non-magnetic and non-conducting dielectrics. So I know that the ratio of Er/Ei and...
  21. N

    Normal derivative at boundary Laplace's equation half plane

    Hi, Given a holomorphic function u(x,y) defined in the half plane ( x\in (-\infty,\infty), y\in (-\infty,0)), with boundary value u(x,0) = f(x) , the solution to this equation (known as the Poisson integral formula) is u(x,y) = \int_{-\infty}^{\infty} \frac{y\ f(t) }{(t-x)^2 +y^2} \...
  22. C

    Probability Functions and Distributions for Independent Series of Experiments

    Homework Statement Two independent series of experiments are performed. The probability of a positive result (independent of each other) in the respective series are given by p and q. Let X and Y be be the amount of experiments before the first negative result occur in the respective series...
  23. W

    Embedding Group as a Normal Subgroup

    Hi, let G be any group . Is there a way of embedding G in some other group H so that G is normal in H, _other_ than by using the embedding: G -->G x G' , for some group G'? I assume this is easier if G is Abelian and is embedded in an Abelian group. Is there a way of doing this in...
  24. R

    Can somebody explain boundary conditions, for normal modes, on a wire?

    I don't really understand boundary conditions and I've been trying to research it for ages now but to no real avail. I understand what boundary conditions are, I think. You need them along with the initial conditions of a wire/string in order to describe the shape of motion of the string. I...
  25. V

    Prove that U_{m/n_1} (m) ,U_{m/n_k} (m) are normal subgroups

    prove that U_{m/n_1} (m) , ... U_{m/n_k} (m) are normal subgroups In the attached image I have proved that U_{m/n_1} (m) , ... U_{m/n_k} (m) are normal subgroups But how do i Prove that U(m) = U_{m/n_1} (m) ... U_{m/n_k} (m)? and that their intersection is identity alone. Help will be...
  26. R

    Finding the MVUE of a two-sided interval of a normal

    Our task is to determine if P(-c \le X \le c) has a minimum variance unbiased estimator for a sample from a distribution that is N(\theta,1). The one-sided interval P(X \le c) = \Phi(x - \theta) is unique, so constructing an MVUE is just a matter of applying Rao-Blackwell and Lehmann-Scheffe...
  27. M

    Example about tangential and normal unit vectors

    Here is a example 1.3 from analytical dynamics of Haim Baruh. a particle moves on a path on the xy plane defined by the curve y=3*x^2 , where x varies with the relation x= sin(a). find the radius of curvature of the path and unit vectors in the normal and tangential directions when a=pi/6...
  28. R

    Form of the displacement, y(x,t), for the normal modes of a string

    Homework Statement The displacement, y(x; t), of a tight string of length, L, satisfies the conditions y(0, t) = \frac{\delta y}{\delta x}(L,t) = 0 The wave velocity in the string is v. a) Explain what is meant by a normal mode. Give the form of the displacement, y(x; t), for the normal...
  29. applestrudle

    Group velocity dispersion and normal, anomalous dispersion?

    From my understanding, normal and anomalous dispersion are because the phase velocity is a function of k so it is different for different components of a group so the group will spread out over time. So what's group velocity dispersion? Is it the same affect (dispersion/ spreading out)...
  30. F

    How Does Speed Affect Normal Force at the Crest of a Hill?

    Homework Statement A 1300 kg car is traveling at 25 m/s as it passes the crest of a hill that has a radius of curvature of 120m. Determine the normal force acting on the car at the crest of the hill.Homework Equations The Attempt at a Solution I know that for horizontal surfaces the Normal...
  31. M

    Drift speed of an electron in normal atmospheric conditions

    Homework Statement How fast would a electric arc be when it ionizes through normal, unpressured air between say, two electrodes? Not the same as lightning as it is hypothetically from an artificial source. Homework Equations How would one calculate (please include your formula's and which...
  32. M

    MHB Normal form of the differential equation

    Hey! :o I have the following exercise: Write in the normal form the differential equation $$u_{xx}+\frac{2y}{x}u_{xy}+\frac{y^2}{x^2}[(1+y^2)u_{yy}+2yu_y]=0$$ Hint: You can suppose that the one new variable is given by $\xi=x$ I have done the following: $a=1, b=\frac{y}{x}...
  33. D

    Computable Normal Numbers: Is There a Known Answer?

    Wikipedia is not very clear on this. Is there a known computable normal number? I found this paper: http://www.glyc.dc.uba.ar/santiago/papers/absnor.pdf But I'm not sure if it's been peer reviewed.
  34. S

    Finding the Normal Force on the Rod of a Paper Roll

    Homework Statement A large 16.0 kg roll of paper with radius R=18.0 cm rests against the wall and is held in place by a bracket attached to a rod through the center of the roll. The rod turns without friction in the bracket, and the moment of inertia of the paper and rod about the axis is...
  35. A

    Maximum gradient of a normal to the curve

    Homework Statement complete problem attached Homework Equations The Attempt at a Solution part I in this question was a bit tricky but i managed to solve it , when i read part II i understood nothing , he usually asks about the tangent not the normal , he asks about the point...
  36. T

    Normal stress boundary condition at fluid/vacuum interface

    Homework Statement Stuck on two similar problems: "State the normal stress boundary condition at an interface x_3-h(x_1,x_2,t)=0between an invisicid incompressible fluid and a vacuum. You may assume that the interface has a constant tension." The second question in the same but the fluid is...
  37. S

    Normal Force in Space: Ball on Table in Spacship

    imagine there is a ball on a table on a spaceship that is not moving there is no gravitational force acting on the ball will there be a normal force
  38. E

    Does the Normal Force Do Work on an Inclined Plane?

    Homework Statement Consider the mass m1 on a simple incline plane. It passes from point A downwards with the velocity v0 and stops at point B (still on the plane). What is the work done by the normal force on mass m during the complete motion? Homework Equations The Attempt at a...
  39. Giant

    Schools Open University degree vs normal degree

    Is the open university degree same as a regular degree? I want to obtain a major of physics from an Indian university. So after I finish with all the course requirement and obtain a mathematics degree from open university (UK), am I considered as a double major by the employers? The reason...
  40. R

    MHB Transform Random Var CDF to Standard Normal: F(x)=1-exp(-sqrt x)

    How to transform a random variable CDF to a standard normal Given F(x) = 1- exp (-sqrt x), for x greater that 0 Thanks.
  41. gfd43tg

    Normal Shock Table: P02/P01 & P1/P02 Meaning

    Hello, I am wondering, on a Normal Shock Table, what are the two most right columns supposed to mean? What is the ratio P02/P01 and P1/P02 supposed to be?
  42. S

    Is the Image of a Normal Operator the Same as Its Adjoint?

    Homework Statement Show that if T is a normal operator on a finite dimensional vector space than it has the same image as its adjoint. Homework Equations N/A The Attempt at a Solution I have been able to show that both T and T^{*} have the same kernel. Thus, by using the finite...
  43. K

    Understanding Normal Ordering: Anhillation and Creation Operators Explained

    In normal ordering method the anhillation operators are put in the left and creation operators on the right. What happens when we try to normal order the product of two anhillation operators or two creation operators (as in the case of complex scalar fields). What are we doing there actually...
  44. F

    Minkowski normal v. Euclidean normal

    What is the difference between the normal in Minkowski spacetime and the normal in Euclidean space?
  45. Z

    Elasticity: Determine zero normal stress plane

    Given the stress tensor in a point, determine the zero normal stress plane. ...2 3 0 T= 3 2 0 ...0 0 5 ---------------------- Eigenvalues: σ1=σ2=5, σ3=-1 It must be simple, but I don't know how to determine the normal vector of that plane analytically. I know σ=0. t=Tn=σ+τ=τ If normal stress...
  46. S

    Converting Normal Distribution to Standard Normal

    Homework Statement Let X1,X2,X3 be a random sample from a normal distribution with mean μ≠0 and variance σ2=1/24. What are the values of a and b, respectively, in order for L=aX1+4X2+bX3 to have standard normal distribution?Homework Equations σ=1/√24 Converting normal distribution to...
  47. N

    Why is the Normal Force Neglected in Certain Scenarios?

    So why does normal force of the wheel not counted or drawn in the diagram?? Isn't it that whenever there's mg, there's also Fnormal? Thanks!
  48. Demon117

    Geodesic curvature, normal curvature, and geodesic torsion

    I am struggling to make sense out some things. Hopefully someone can help or at least offer some different point of view. Let's examine a differential curve parameterized by arc length that maps some interval into an oriented surface (lets call it N(s)). The surface has a unit normal field...
  49. P

    Normal tangential co-ordinates(ut,un)

    Homework Statement A jet is coming out of a dive and a sensor in the pilots seat measures a force of 800lb for a pilot whose weight is 180lb. If the jet's instruments indicate that the plane is traveling at 850mph, determine the radius of curvature, p, of the plane's path at this...
  50. S

    MHB Two dimensional normal distribution

    If $$( X,Y )$$ has the normal distributions in two dimensions with zero means and unit variances and the correlation coefficient $$ r$$, then how to prove that the expectation of the greater of $$X$$ and $$Y$$ is $$\sqrt{(1-r)\pi}$$?
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