Origin Definition and 688 Threads

  1. S

    What is the net electric force on the charge at the origin?

    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...
  2. Q

    Changing Origin in Physical Context: Mathematical Approach

    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.
  3. J

    What is the Mechanism Behind the Emission of Thermal Radiation?

    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...
  4. M

    Resultant Torque independent of origin?

    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...
  5. A

    What will be the acceleration of an electron when it is at the origin?

    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...
  6. S

    Origin of the equation c^2=1/epsilon_0*mu_0

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

    Origin of thermal radiation in humans.

    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...
  8. V

    Unraveling the Mystery of the Universe's Origin

    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?
  9. A

    Unraveling the Mystery of Inertia: The Search for its Origin

    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...
  10. A

    Plane through origin perpendicular to another plane?

    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...
  11. nomadreid

    On a point of logic in the Higgs vs strong force origin of mass

    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...
  12. C

    Invariance of energy under change of origin

    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...
  13. S

    Origin of IR radiation in living things ?

    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...
  14. M

    Partial derivative exists at origin but not continuous there

    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...
  15. P

    Finding the magnitude of an object's angular momentum about the origin.

    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...
  16. N

    What is the origin of C,P and CP violations?

    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...
  17. N

    Object Launched from Origin: Time to Reach the Roof

    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...
  18. C

    What is the Origin of Spin 1/2 in Quantum Field Theory?

    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
  19. S

    Reduced Mass: Origin & Significance

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

    Is the estimator for regression through the origin consistent?

    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...
  21. B

    Theoretical Theorys of Magnetic Force and Origin

    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...
  22. S

    Points Nearest/Farthest from Origin on Plane-Paraboloid Intersection?

    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...
  23. S

    Uniqueness and origin of physics theorems

    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...
  24. M

    Translating Graphic back to Origin after Rotation

    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...
  25. A

    Origin of internal magnetic field in an atom

    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...
  26. STEMucator

    How does f(x,y) behave as (x,y) approaches the origin?

    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...
  27. M

    Maximum speed of overdamped oscillator without crossing origin

    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...
  28. N

    X and Y Components of the Electric Field at the Origin

    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...
  29. S

    Probability that distance from the origin of a uniformly distributed point < x

    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...
  30. A

    Origin of the schroedinger's wave equation

    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...
  31. M

    The velocity of a particle at the origin.

    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...
  32. A

    Finding band origin of electronic transition and wavenumber of vibrational mode

    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...
  33. F

    Translating a linear system to have critical points at the origin?

    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...
  34. M

    Distance from a plane to the origin question

    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...
  35. D

    High Energy Cosmic Rays and the Origin of Life

    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...
  36. A

    Origin of the depletion region in a p-n junction

    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...
  37. Roodles01

    I have a hertzian dipole at the origin

    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...
  38. E

    Expressing a vector with respect to another vectors origin

    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...
  39. W

    A very basic question about the the origin of quantum levels

    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...
  40. O

    What is the primary source for the origin of elements?

    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...
  41. O

    Exploring the Origin of Elements to Nucleosynthesis and Fusion in Stars

    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...
  42. B

    On the Origin of Solar and Stellar Magnetic Fields

    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...
  43. G

    Determine Origin to Rotate Vector B to Equal A

    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...
  44. I

    What Lies Beyond the Expanding Universe?

    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...
  45. J

    Center of the universe the origin of the big bang?

    can we calculate the orgin of the big bang based on the wmap and drift of galaxies?
  46. johann1301

    Does Higgs-particle explain origin of inertia?

    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...
  47. R

    What is the Origin of the Electric Field in F-N-L's Law?

    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...
  48. G

    Find the tangent line that passes through the origin

    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...
  49. edguy99

    Nobelist David Gross Lecture on Fund. Theory of Physics at UCSB

    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...
  50. H

    Origin of Magnetism: Exchange Coupling Existence

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