Normal Definition and 1000 Threads

As I try to set up equations regarding Newtonian forces, I am looking for patterns in example problems I read. It's really frustrating then when I see different approaches that I can't see a connection to. There are two problems that I've attached that seem to solve - what seems to me about...

Homework Statement Let G = G1 × G2 be the direct product of two simple groups. Prove that every normal subgroup of G is isomorphic to G, G1, G2, or the trivial subgroup. The Attempt at a Solution I tried proving that the normal subgroups would have to be of the form Normal subgroup X Normal...

Homework Statement why the object will fall of when the normal reaction force is less than zero ? P/s : the normal reaction force is in downward direction... How if if the normal reaction force is less than zero ? the normal reaction is in upward direction ? Homework EquationsThe Attempt at a...

Hello, I am returning to college after a ten year hiatus and am taking an online course on edx to try and refresh my knowledge a bit before the fall. I read a few other posts on Newton's Third law, but it seems I am falling short on this one concept. In the case of an object, m_1, which is at...

Homework Statement As you can see , the writer state that the direction of normal reaction force(R) is acted upwards , I have another book state that the normal reaction force (R) is acted downwards , which one is correct ? Homework EquationsThe Attempt at a Solution [/B]

Homework Statement The Particle moves in the plane in a such a way that its polar equation of motion is ## \vec{R}=t\vec{i}+(t^2+1)\vec{j}##. a)What are its normal and tangential components of accelaration any time t ? b)Whats the curvature of path any time t ? Homework...

Homework Statement Find a unit normal to the plane containing a and b. a=(3;-1; 2) and b=(1; 3;-2) Homework Equations \frac{V}{|V|} where V = a+b The Attempt at a Solution (3;-1; 2) +1; 3;-2)=(4,2,0)=V |V| = \sqrt{4^2+2^} = 2\sqrt{5} there fore the unit vector is (\frac{2}{\sqrt{5}}...

A Google image search of "normal blood pressure versus age" came up with charts that I don't understand completely. Consider the following information. Also see, http://www.betterhealthfacts.com/2014/02/normal-blood-pressure-for-men.html It looks like it is normal for blood pressure to rise...

Hey everybody, I went through a discussion with a colleague today about Finite element modeling of composite structures and how to interpret the stress analysis. I understand that for isotropic materials, principal stresses could be used against the allowable stresses to see if failure will...

Hi, ##x(s)=\cos\frac{s}{\sqrt{2}}## ##y(s)=\sin\frac{s}{\sqrt{2}}## ##z(s)=\frac{s}{\sqrt{2}}##, it is a unit-speed helix. Its curvature is ##\kappa=||\ddot{r}||=\frac{1}{2}##. Principal unit normal is ##{\mathbf n}=(\cos\frac{s}{\sqrt{2}},\sin\frac{s}{\sqrt{2}},0)##. So far so good... But the...

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...