Normal Definition and 1000 Threads

I'm unsure on how to start this problem. I tried to make a tree diagram but to no avail did it help out. Question: On average, Mike Weir scores a birdie on about 20.9% of all the holes he plays. Mike is in contention to win a PGA golf tournament but he must birdie at least 4 holes of the last 6...

In p.244 of Carroll's "Spacetime and Geometry," the Killing horizon ##\Sigma## of a Killing vector ##\chi## is defined by a null hypersurface on which ##\chi## is null. Then it says this ##\chi## is in fact normal to ## \Sigma## since a null surface cannot have two linearly independent null...

Homework Statement A 42 kg wagon is being pushed with a metal rod that makes an angle of 46 with the horizontal. The applied force is 449 N and the coefficient of kinetic friction between the wagon and the ground is 0.21. I'm not sure what equation to use to find the normal force and then the...

Hey! :o I am looking at the following: 1) A machine produces $100$ gram chocolate. Due to random influences, not all bars are equally heavy. From a long series of observations it is known that the mass X of a chocolate is distributed normally with parameters $\mu = 100$g and $\sigma = 2.0$g...

Homework Statement Express the charge Q in terms of the creation and annihilation operators. Homework Equations $$\phi_{(x)}=\int \dfrac {d^3 p} {(2\pi)^3} \dfrac {1} {2 \omega_p} (a_p e^{i x \cdot p} + b^{\dagger}_{p} e^{-i x \cdot p})$$ $$\pi_{(x)}=\dfrac {-i} {2}\int \dfrac {d^3 p}...

Homework Statement "In a component under multi-axial state of stress, the ratio of shear stress to normal stress along principle places is _____. A) 0.0 B) 0.5 C) 1.0 D) 1.5 E)2.0" Homework Equations σx' = (σx+σy)/2 + ((σx-σy)/2)*cos(2θ) + τxy*sin(2θ) σy' = (σx+σy)/2 - ((σx-σy)/2)*cos(2θ)...

Homework Statement In this diagram, I wondered if there is any torque due to the normal force from the hinge, once the support stick is removed. I also want to know what the normal force would be at the hinge. The cup and ball are to be ignored here (essentially massless). Homework Equations...

Well, we all know that normal force is the force that keeps things from falling to the center of the earth, right? Well, that should apply to horizontal surfaces such as the ground. But does normal force work for vertical and diagonal forces such as a wall, too?

Homework Statement A spring with spring constant k is attached to a box of mass M in which is placed a small body of mass m. The system is displaced a distance A from equilibrium and released from rest. Find the normal force between the box and the small mass as a function of time. For what...

I did torque and equilibrium lab report, where I had to hang some weights on a meter stick, which was placed on a fulcrum. There were 3 parts for the lab, with different settings. I am stuck at the last part, where I hang the meter stick with a string over a pulley, and there were 4 weights...

Homework Statement Is the gradient of a plane, the normal to the plane? If so, why? Homework Equations No idea, just a question that popped up in my head eon of plane: n(x-x1)+n(y-y1)+n(z-z1) The Attempt at a Solution I found the partial derivative of each, and got the normal.[/B]

Homework Statement For the state of stress shown in the figure, normal stress acting on the plane of maximum shear stress is? Homework Equations Normal stress σn = σcos2θ 3. The Attempt at a Solution Plane of maximum shear stress is 45o relative to the max stress of 100MPa. So the total...

I am not sure where to ask this question but I must try somewhere. 1. Homework Statement I am trying to graph a simple cdf on my ti-84 and I cannot get it to work. I need an example to follow Homework Equations See below. The Attempt at a Solution 2nd, dist, 2 enter -1E99,0 0,.5 [/B]I also...

Homework Statement Say I have two objects on top of each other in an elevator (say Object 1 on the bottom and Object 2 on top), each with a given mass. The elevator is accelerating downward (meaning the elevator is moving up and slowing down). What would the normal force be on Object 1...

Homework Statement Find the normal form of the equation of the plane that contains the point P=(0, 1, 0) and has normal vector n=[3, 2, 1]. Homework Equations None. The Attempt at a Solution I know that the general form: ax+by=c since that's written in my textbook. But why is the answer...

If someone was sliding down a vertical pole (like a firefighter) would only friction need to be considered to find out how fast the person is "falling" or is there also normal force from where the person is touching the pole, and would that affect the person's speed down? (I am ignoring air...

I have proved (8.1). However I am trying to prove that ##\bar{X},X_i-\bar{X},i=1,...,n## has a joint distribution that is multivariate normal. I am trying to prove it by looking at the moment generating function: ##E(e^{t(X_i-\bar{X})}=E(e^{tX_i})E(e^{-\frac{t}{n}\sum_{i=1}^n X_i})## I am...

Homework Statement Given g(x,y)=x2 - xy + 2y2, find the equation of the line normal to the contour that passes through the point (1,2). Homework Equations Not 100% positive, but the equation to a plane tangent to a function of 3 variables g(x,y,z) is (partial of x)(x - x0) + (partial of y)(y -...

1. The problem statement, all variables, and given/known data A somewhat paraphrased version of the problem: Consider the vertical motion of the center of mass of a 150 lbs person as they run along a track. Suppose the person's cadence is 4 steps per second, and with every stride, they briefly...

In my current math class, we are constantly leap frogging throughout the text. In week 1, we did a couple things from chapter 6, not going through it fully- just a few sections here and there. In week 2, we went to chapter 3, again only doing a couple sections somewhere in the middle of the...

Homework Statement A book is placed on a chair which is standing on the floor. An iPad is placed on the book. The floor exerts a significant force: A) only on the book B) Upwards on chair and downwards on book C) ONLY upwards on chair D) upwards on chair book and iPad E) downwards on...

Homework Statement https://ibb.co/imui5b[/B] hey i need to calculate max normal stress at BC and max shear stress at b and c is my torque equation right? Homework EquationsThe Attempt at a Solution so i thought Σma=0 Cx*6+80*6+80*2=0 i ll find cx and then ΣFx=0 and ΣFy=0

$\textsf{write an equation for}$ $\textsf{ The plane through the point (3, 2, -5) and perpendicular to the x-axis}$ 4ok I know this goes thru $3$ on the axis and it is \parallel to the $yz$ plane so is it just $x=3$.

Why would normal modes occur in the coupled oscillator system I.e. why the parts of system would oscillate with constant angular frequency and constant phase difference ?

Homework Statement A roller coaster car has a mass of 500 kg when fully loaded with passengers. The path of the coaster from its initial point involves only up and down motion with no motion to the left or right. (A) If the vehicle has a speed of 20 m/s at the bottom of the first dip which...

So this is the problem: A 250-kg crate is on a rough ramp, inclined at 30° above the horizontal. The coefficient of kinetic friction between the crate and ramp is 0.22. A horizontal force of 5000 N is applied to the crate, pushing it up the ramp. What is the acceleration of the crate? Relevant...

Hi. I'm trying to self-study vector calculus and I have to admit I struggle with it. As regards finding normals to a surface I know 2 ways - one involves writing the surface equation as f(x.y.z) = 0 and taking the gradient. The other method involves writing the surface in terms of 2 parameters...

(a) We are told $\displaystyle \begin{align*} \textrm{Pr}\,\left( X < 3 \right) = \textrm{Pr}\,\left( Z < a \right) \end{align*}$, so if $\displaystyle \begin{align*} x = 3 \end{align*}$ and $\displaystyle \begin{align*} z = a \end{align*}$ then we have $\displaystyle \begin{align*} z &=...

Homework Statement With two fingers, you hold an ice cream cone motionless upside down, as shown in the figure. The mass of the cone is m and the coefficient of static friction between your fingers and the cone is μ.μ When viewed from the side, the angle of the tip is 2Θ. What is the minimum...

Hi All, I am looking at the page http://www.visiondummy.com/2014/04/geometric-interpretation-covariance-matrix/ In which White Noise in 2D is defined as the/a graph of uncorrelated data, so that the associated co. It is sassociated covariance matrix is the identity. It is stated at one point...

Homework Statement What is the equation of a straight line passing through (1,2) and normal to ##~x^2=4y## Homework Equations Slopes of perpendicular lines: $$m_2=-\frac{1}{m_1}$$ The Attempt at a Solution $$x^2=4y~\rightarrow~m_1=y'=\frac{x}{2}$$ $$m_2=-\frac{2}{x}$$...

Dear community, I am very ashamed to have not noticed this result but well into my physics major, and I would like to share it with you. I am not sure it is right, which is my reason for posting it. The normal force is classically referred as...

Hello! I am reading some representation theory (the book is Lie Algebra in Particle Physics, by Georgi, part 1.17) and the author solves a problem of 3 bodies connected by springs forming a triangle, aiming to find the normal modes. He builds a 6 dimensional vector formed of the 3 particles and...

Homework Statement Homework Equations The equation has already been given in the question. The Attempt at a Solution So what I did was find r'(t), r"(t), v(t), v'(t) and plug it into the equation. I've done 3 different full pages of this and have gotten 3 different answers. I'm guessing due...

What is actually the unit normal vector of a surface? Is it this? Or this one? I see that those are opposite in direction. But, I want the correct one, which means that it should point outward. So, which one is correct?

HI, Can the normal force be in vertical direction ?

Homework Statement Suppose that X ~ N(μ,σ). Find a in terms of μ and σ if P(X>a) = 1/3 * P(X ≤a) Homework EquationsThe Attempt at a Solution 1 - P(X ≤a) = 1/3 * P(X ≤a) 3 = 4P(X ≤a) P(X ≤a) = 3/4 Since x0 = μ + σz0 where x0 and z0 are the same percentile for N(μ,σ) and N(0,1)...

In the derivation of Navier Stokes equation there is a term for normal stress acting on the fluid element. While the cause of normal stress is the static pressure which is already present in the equation doesn't this mean that the same force on the fluid element is repeated twice with different...

Homework Statement Show that if T is normal, then T and T* have the same kernel and the same image. Homework Equations N/A The Attempt at a Solution At first I tried proving that Ker T ⊆ Ker T* and Ker T* ⊆ Ker, thus proving Ker T = Ker T* and doing the same thing with I am T, but could not...

Homework Statement https://1drv.ms/b/s!ApJAu5EMYb4JgpYy68UWlGVzp0PVLQ Problem 21 Homework Equations [/B] x1 = Aeiw0t + 3Be2iw0t x2 = 3Aeiw0t - Be2iw0tThe Attempt at a Solution [/B] At t = 0 both masses at equilibrium so the above equations simplify to: 0 = A + 3B 0 = 3A - B Thus B =...

Without knowing whether WIMPs or axions or something else are what dark matter is composed of, can we speculate about the vacuum density creating only normal matter, and by what mechanism?

Homework Statement This problem is from "Fundamentals of aerodynamics" by John D. Anderson, Jr (Fifth edition, page 101): Consider a flat plate at zero angle of attack in a hypersonic flow at Mach 10 at standard sea level conditions. At a point 0.5 m downstream from the leading edge, the local...

Homework Statement A company allows a maximum failure rate of 1 out of 250,000 parts. To insure this quality goal, failed parts must be how many standard deviations from the mean? Use Excel to solve. Homework Equations z= (X-μ)/σ The Attempt at a Solution Hi! So I'm assuming that this is a...

Homework Statement The random variable X is normally distributed. The values 650 and 850 are at the 60th and 90th percentile of the distribution of X respectively. Find the value of the 75th percentile of the distribution of X. Homework Equations I found the above formula from internet. where...

I am interested in looking at the metric where time is everywhere normal to space, so gta=0 everywhere, where t is the time coordinate and 'a' is any of the space coordinates. I'm finding it hard to look up in the literature: does it have a name that I can search for? My main interest is in...

Homework Statement The Attempt at a Solution Can somebody please assist me in finding the direction of the normal force exerted on B? (How is normal force at B also normal to the rod? ) There is no hint provided from which I can conclude the direction of normal force. Can somebody please...

Homework Statement Let ##\{N_i ~|~ i \in I\}## be family of normal subgroups of G such that (i) ##G = \left\langle \bigcup_{i \in I} N_i \right\rangle## (ii) for each ##k \in I##, ##N_k \cap \left\langle \bigcup_{i \neq k} N_i \right\rangle = \{e\}## Then ##G \simeq \prod_{i \in I}^w...

Homework Statement The system shown is initially at rest when the bent bar starts to rotate about the vertical axis AB with constant angular acceleration a 0 = 3 rad/ s2 . The coefficient of static friction between the collar of mass m = 2 kg and the bent bar is f.Ls = 0.35, and the collar is...

Homework Statement A 74.0 kg person is standing inside an elevator. The elevator is moving from the 3rd floor to the 21st floor. As the elevator passes the 4th floor it is moving at 2.30 m/s and is increasing speed at a rate of 1.43 m/s2 . At this moment, what is the normal force that acts on...

Hello! I am not really sure I understand the idea of tensors and the difference between them and normal matrices, for example (for rank 2 tensors). Can someone explain this to me, or give me a good resource for this? I don't want a complete introduction to GR math, I just want to understand the...