Origin Definition and 688 Threads

Homework Statement Consider three charges in a triangle as shown. 1. What is the net electric force on the charge at the origin? 2. What is the direction of this force(between -180 and 180)? 3. What is the magnitude of the net electric field at the position of the charge at the...

In a general situation, how do you change origin (mathematically speaking) in a physical context i.e. with position vectors, constant vectors, unit vectors to certain directions ... ? I am a bit confused with the concept.

I'm trying to understand the origin of thermal radiation. All things with a temperature emit electromagnetic radiation. Every discussion I've found starts with that as a premise and then goes on to Wien's displacement law and Planck's law, etc which I follow. But *why* do all things...

Homework Statement Let a system of forces (F1,...Fn) act on a body at points (x1,...xn) respectively. Assume that the resultant or net force vanishes (sum of forces = 0) Show that the resultant torque of this system is independent of the choice of origin, i.e. for 2 different origins x0...

1. +3.00μC point charge is at x=1.00cm and y=.750cm. -2.50nC point charge is at x=0 and y=-5.00mm. What will be the acceleration of an electron (Me=9.109X10^-31 kg) when it is at the origin (only force acting on the electron is the Coulomb force)? 2. K=8.988X10^9 N(m^2/c^2) Fc= K(qs...

Hello, Could someone describe the origin of the equation c2=1/ε0μ0 Is it derived from fundamental reasons? Thanks.

hi, i m new to this forum,this is my first post,i have recently started studying heat transfer. i m am little bit confused about the origin of thermal radiation in human beings.i mean radiations are emitted when an electron jump from a shell/orbit which is far from the nucleus to a shell which...

Hi all, Suppose we find the first cause that created the universe. What about the origin of this very first cause? Suppose it is X. What about the origin of X? Suppose it is Y. What about Y? And so on... Can we ever find the origin of this universe?

What is the origin of inertia? This is a question asked by many people. I believe even Einstein pondered on this and did put some of his thoughts in a paper, but nothing really conclusive. In Newtonian gravity, inertia appears to be just something that is inherent to mass. However, given...

Homework Statement Find a plane through the origin that meets the plane M : 2x + 3y + z = 12 in a right angle. How do you know your plane is perpendicular to M? Homework Equations Honestly have no idea... I know how to find an equation for a plane given a normal and a point, however...

Recently, in the Scientific American blog http://blogs.scientificamerican.com/observations/2012/11/29/person-of-the-year-nomination-for-higgs-boson-riddled-with-errors/?WT_mc_id=SA_CAT_physics_20121130 the author criticizes Time Magazine for its science reporting, which of course is nothing...

Suppose you have a particle in one dimension in an energy eigenstate, i.e. Hψ(x)=Eψ(x) for some E. For an observer B in a coordinate frame with the origin translated some distance K to the right, the wavefunction of the particle looks like ψ'(x) = ψ(x+K). Surely, we expect the energy that B...

Hi, I've been reading that in a relatively normal environment about 1/2 of human heat loss is due to radiation. Most of this seems to have a wavelength of 10-12 μm. Could someone here speak to the molecular origin of this? I'm guessing it is mostly from water molecules going from a higher...

I always see the example f(x,y)={xy/(x2+y2) if (x,y) =/= (0,0) and 0 if (x,y)=(0,0)} given as the example of a function where the partial derivatives exist at the origin but are not continuous there. I have a difficult time wrapping my head around this and was hoping someone could...

Homework Statement A 1.4 kg object at x = 2.00 m, y = 3.10 m moves at 4.9 m/s at an angle 45° north of east. Calculate the magnitude of the object's angular momentum about the origin. Answer is 5.3 kg m^2 /s Homework Equations These were the only three I could think of: L=Iω L=mvr ω=v/r The...

The C and P symmetry violations are deduced from the separating the right-handed representation from left-handed representation in electroweak model(Weinberg theory).Then I do not understand why we can consider the left-handed fermions living in a representation separating with that of...

An object is launched from the origin with a velocity of 20 m/s at an angle of 30 degrees above the x axis. The object lands on a roof that is 4 meters high. What is the time when the object hits the roof? a) 1.11 s b) 1.27 s c) 1.33 s d) 1.49 s e) 1.67 s I did 20 (sin(30)) = 10 m/s...

Dear Forum, I would like to understand what the origin of spin 1/2 is. I read in Feynman's lectures that the origin is related to quantum field theory. I know nothing about quantum field theory. Is there an easy explanation? Thanks Cabrera

Will anyone help me to understand the concept of reduced mass , where does it come from and its physical significance

Homework Statement Any help on this would be immensely appreciated! I am having trouble interpreting what my instructor is trying to say. Consider a simple linear regression model: y_i = \beta_0 + \beta_1x_i + u (a) In regression through the origin, the intercept is assumed to be equal to...

Does anyone have a good theory for magnetic force? No need to talk about domain alignment or electron spin, (although if you have something deeper then just electron spin, id love to hear it)this much is known. I'm talking about the actual FORCE of magnetism. As in: If you are in a vacuum...

Homework Statement Find the points nearest and furthest from the origin on the intersection of a plane with a paraboloid. Plane: x+y+2z=30 Paraboloid: z=x^{2}+y^{2} Homework Equations The Attempt at a Solution Obviously the first step is to find the equation of the...

After studying some of the proofs of equations, worries arises about their uniqueness. 1.Removal of integral ∫∇．Edτ = ∫(ρ/ε)dτ →∇．E = Q/ε 2.Removal of (∇X) ∇XE = ∂B/∂t = ∂(∇XA)/∂t →∇X(E+∂A/∂t)=0 →E+∂A/∂t=-∇V →E=-∇V-∂A/∂t Origin - Certain physics equations/theorems have no...

I'm developing a game for the iPhone, and I have a situation where I have a graphic that the user can drag around the screen and there are some buttons the user can push to both rotate it and enlarge it. The graphic is located within a UIView, which is just a rectangular shape that fits tightly...

What is the origin of the internal magnetic field in an atom (which gives rise to spin-orbit interaction in an electron). The energy associated with this field is calculated using the reference frame of the electron and then returning back to the nucleus reference frame (thomas precision). But...

Homework Statement Let f(x,y) be defined : f(x,y) = 0 for all (x,y) unless x4 < y < x2 f(x,y) = 1 for all (x,y) where x4 < y < x2 Show that f(x,y) → 0 as (x,y) → 0 on any straight line through (0,0). Determine if lim f(x,y) exists as (x,y) → (0,0). Homework Equations Polar co - ordinates...

Homework Statement An overdamped oscillator with natural frequency w and damping coefficient g starts out at postion x0 > 0. What is the maximum initial speed towards the origin it can have without crossing the origin? Homework Equations x(t) for overdamped oscillator The Attempt at...

Homework Statement Assume that you have a configuration of conductors with varying electric potentials applied to each. You make the following measurements of the values of the electric potential at different points in a two dimensional grid: X = 0.0 cm Y = 0.0 cm V = 2.0 volts X = 2.0...

Homework Statement A point is uniformly distributed within the disk of radius 1. That is, its density is f(x,y) = C For 0 ≤ x2 + y2 ≤ 1 Find the probability that its distance from the origin is less than x, 0 ≤ x ≤ 1. [Note] My book says that the answer is supposed to be x2. 2. The attempt...

How did schroedinger arrive at the wave equation? I recently read in a book about the concept of wave packets using Fourier analysis and the wave equation was derived by forming a differential equation of the Fourier integral. But some books say that there is no formal proof of the...

Homework Statement A particle moves according to the position function x(t)=ct2+bt where c=3m/s2 and b=-7m/s. Find the velocity at the origin. 2. The attempt at a solution I tried just taking the derivative and setting t=0 to the equation as so: vx(t)=6t-7=6(0)-7=-7 m/s Although, when...

Homework Statement The first vibrational band in the absorption spectrum of H2CO is at 28871 cm-1. The first two bands in the emission spectrum (from v'=0 level) lie at 27021 cm-1 and 24687 cm-1. Explain these observations. Determine the band origin of the electronic transition and the...

So suppose you have a nice simple linear system dx/dt = a1x + b1y + c1 dy/dt = a2x + b2y + c2 and a critical point (x0, y0) ≠ (0,0). If you want to analyze the stability in the usual linear method, then I assume there should be some transformation to have the critical point at the origin. So is...

Hi, I have the following question: Find the perpendicular distance from the origin to the plane x + 2y + 2z = 6. My solution is incorrect but I can't find what's wrong. I did this: I know that the distance will be a vector from the the origin to the plane, and it will be along a normal...

The advocators of Darwin’s theory of evolution discover that it is difficult for normal evolution rate alone to form the species diversity now. What factor(s) accelerated the origin of life and species diversity? Reference viewpoints: Novae, especially supernovae, would generate high energy...

Hi the first step to this is usually described as diffusion of electrons from the n type to the p type. However I have encountered sites and books that state that holes diffuse from p type to n type as well. I am of the opinion that only the electrons diffuse, and that there is no diffusion of...

Homework Statement I have a hertzian dipole at the origin, generating a signal. Nearby in empty space there is a loop, at a position vector r=(50m)ezz which can detect this signal. Homework Equations I have the equation B(t) = B0 sin (2*pi*ft)ex which I understand is the signal emitted...

Homework Statement Given that A_vec = 3*r_hat - 7*theta_hat + 2*phi_hat w/ origin at (1, pi/2, 0 (deg)) and B_vec = -2*r_hat - 4*theta_hat + 2*phi_hat w/ origin at (3, pi/2, pi/2). The vectors are represented in Spherical Coordinates. Determine A - B with respect to A, and with respect...

Does anyone know why quantum states exist? In other words, is there an explanation for why the universe is built from discrete levels vs. some other system? I've scanned over numerous books on quantum mechanics and the history of quantum mechanics but I can never find a layman's answer to this...

By choosing among the following five options, what is the main source in the universe for the origin of the elements : silicon, lithium, bismuth, nickel and uranium? Primordial nucleosynthesis – fusion in core of low-mass stars – fusion in core of high-mass stars – slow neutron capture in...

By choosing among the following five options, what is the main source in the universe for the origin of the elements : silicon, lithium, bismuth, nickel and uranium? Primordial nucleosynthesis – fusion in core of low-mass stars – fusion in core of high-mass stars – slow neutron capture in...

On the Origin of Solar and Stellar Magnetic Fields There is recent evidence that the solar magnetic cycle has been interrupted. This is a link to Livingston and Penn’s paper that notes the magnetic field strength of newly formed sunspots is decreasingly linearly. Specifically, why the...

Given two 2D unit vectors (A and B) in different directions and positions in the same horizontal plane, is it possible to determine the origin (point of rotation) required to make vector B = vector A (same position and direction)? All this assuming that vector B is a rotated (only) version of...

I prefix this by saying I have never ever studied science nor was I even interested in it till after high school but the other day I had this thought. While we can maybe one day explain the universe. How will we ever explain the space its expanding into and how big is that space? This...

can we calculate the orgin of the big bang based on the wmap and drift of galaxies?

We know that the Higgs-particle gives an explanation as to why there is mass in the universe. But mass has another property/ability. It has the ability to resist change in its state of motion. Is this ability - inertia - explained by the discovery of the Higgs-particle? Does Higgs-particle...

Good evening. Can anyone explain me the origin of the electric field in the F-N-L's law ? I'm referring to this one : \int_l \vec E^* d\vec l =-\int_s \frac{\partial \vec B}{\partial t} d\vec S where \vec E^* is defined as (i'm reporting the words of the book) : \vec E - \vec v \times...

Homework Statement This problem is 2.95 of University Physics, 11th edition. Catching the Bus: A student is running at her top speed of 5.0 m/s to catch a bus, which is stopped at the bus stop. When the student is still 40.0 m from the bus, it starts to pull away, moving with a constant...

6/12 public lecture today by Nobelist David Gross at University of California, Santa Barbara: What's a fundamental theory of physics? http://www.fnal.gov/culture/NewArts/Lectures/11-12/gross.shtml Dr. David Gross received the Nobel Prize in Physics in 2004, along with H. David Politzer...

does the exchange coupling exists between atoms or between domains in magnetic substances?