Position Definition and 1000 Threads

  1. S

    MHB What is the geometric basis of the method of false position (Regula Falsi)?

    On what geometrical construction is the method of false position (Regula Falsi) based?
  2. D

    Why Does RA Count Down During Retrograde Motion?

    How can I determine Mars' orbital position in February 2009? Is there a website that tracks past positions? By position, I want to know where in its rotation around the Sun it was radians or degrees.
  3. C

    Position of proton and electron to create electric field

    Homework Statement The electric field at a location C points north, and the magnitude is 1*10^6 N/C. Where should you place a proton and an electron, at equal distances from C, to produce this field? Give a numerical answer and a direction for each particle (North, South, East or West)...
  4. D

    Calculating Uncertainty in Position for Scientists

    I have a problem which asks me to calc uncertainty in position..with the help of uncertainity in wavelength, energy n mass all given?? How do I approach to this..?
  5. J

    First interview for a high school physics teaching position tomorrow

    So, after quitting my physics Ph.D grad program last semester, I got my physics teaching license with the aim to be a high school teacher. Teaching and tutoring were my favorite things in undergrad and my one semester in grad school, so I've decided to do it for a living. I have a few months of...
  6. C

    Calculating object position with non-constant speed

    The problem (long story short) to use an analogy... if I stand here, and then immediately run 5mph for an hour, after 30 minutes I have run 2.5 miles. But if I instead linearly drop from 5mph to 1mph over the course of that hour, where do I stand after 30 minutes? The speed is linear so I...
  7. J

    How does a collider know both the energy and position of the particle?

    Presumably a collider has some sort of pinhole out of which particles get ejected in a particular direction, and the energy (momentum) with which they are ejected is supposedly known. So, the operators/designs of the instrument know both the position (at the ejection pinhole, or whatever) and...
  8. M

    Velocity as a function of position problem (simple i think)

    Homework Statement If we know that velocity v of a particle as a funciton of position x is: $$v(x)=20-2/3x$$ then i am asked to determine the acceleration when x=15. I am then asked to show that the particle never actually reaches x=30Homework Equations $$vdv=adx$$ $$vdt=dx$$ $$adt=dv$$ and a...
  9. T

    Operators and the position representation

    I have a question about the formalism of quantum mechanics. For some operator A... \langle x |A|\psi\rangle = A\langle x | \psi \rangle Can this be derived by sticking identity operators in or is it more a definition/postulate. Thanks.
  10. S

    Position, Velocity, Acceleration, and Distance?

    Homework Statement The position of a ball moving on a straight line has an equation of p(t) = 1/3t^3 - 2t^2 +3t , where p is its position and s is time in seconds 1. At what times is the ball at rest? 2. Using its velocity and acceleration, determine the balls DIRECTION and if it is...
  11. Z

    Partial Derivatives of the Position and Velocity Vectors of a Particle

    Hello guys! Lately I've been studying some topics in Physics which require an extensive use vector calculus identities and, therefore, the manipulation of partial redivatives of vectors - in particular of the position and velocity vectors. However, I am not sure if my understanding of partial...
  12. V

    Higher order time derivatives of position

    Newton's laws says ## F=ma ##. Which, as far as I can see, states that all physical interactions concern the second time derivative of position. And because there is no other way for two bodies to interact in the physical world, the "worst" I can do to a system is change its acceleration, right...
  13. D

    Write a program using Bisection method and method of false position.

    Hello everyone. I'm new here and I'm not not a computer science student. But, I have to take programming to complete my degree. So, now I'm in a great depression about this assignment. My lecturer ask me to write a program to find root of an equation f(x)=0 for specific f. Both methods are...
  14. fluidistic

    Eigenvalues of the position operator

    I'm new to QM, but I've had a linear algebra course before. However I've never dealt with vector spaces having infinite dimension (as far as I remember). My QM professor said "the eigenvalues of the position operator don't exist". I've googled "eigenvalues of position operator", checked into...
  15. M

    Position analysis of slider crank like mechanism using loop equations

    Hi Everyone, This is my first post so bare with me. Firstly, a bit of background about the problem. I am designing a near rear drive train for a formula student car which incorporates a chain tensioning device linking the differential to the rear of the chassis. Essentially I am wanting...
  16. A

    A Penny Falling of a Staionary/Fixed Position Sphere

    Homework Statement A penny is released from the top of a very smooth sphere of radius 1.3 meters. The sphere is fixed to a platform and doesn't move. The penny slides down from rest and leaves the sphere at a certain point. How far will the penny fall away from the point of contact of the...
  17. U

    Finding the Minimum Speed of a Particle with Given Position Function

    Homework Statement The position function of a particle is given by r(t) = <2t, 3, -2t+1> where t is the time in seconds. When is the speed a minimum? What is the minimum speed? Homework Equations v(t) = r'(t) The Attempt at a Solution The derivative of r'(t) = 2 + 0 + (-2) = 0. The t is...
  18. T

    How to find equation for a position vector function on a parabaloid?

    Homework Statement Velocity vector given by r'(t)=<cos(t), -sin(t), -2sin(t)> Surface that the position vector needs to lie on: z=x2+y2 Homework Equations Integral of r'(t) will give position function The Attempt at a Solution I know that the integral of r'(t) will give me...
  19. C

    Position of subshells in a bond

    I've learned that there are three types of p shells, namely Px, Py and Pz, each in a different direction. I've also learned that when different atoms bond together, they form specific shapes depending on the number of bonds and electrons. I want to ask, will the shape of the p or d subshells...
  20. D

    Curling simulation position functions

    The Canadian national men's curling competition (the Briar) is going on this weekend and I am motivated to write a computer program to simulate the motion of the rocks on the ice. I see on TV that the rectangular rink 14 by 126 feet appears to be trapezoidal on the screen, with the front about...
  21. E

    Differences in position in 2 very similar circumstances

    I recently read in a book that if i am standing on the top of a moving train and i jump in the air i will land behind my original position. But if i am inside the train and i jump i will land exactly where i was originally! Is this true?? And if it is, then why does this happen?
  22. H

    Global position and orientation of a point relative to another

    Hi there all, I have a personal project I'm working on and since I haven't done any linear algebra in many years I'm not sure what I think is right, is right. I'm also not entirely sure this is the right place to ask but I'm asking more for confirmation/clarification of methodology than...
  23. I

    Finding phi constant based on initial position and initial velocity

    x(t)=Acos(ωt+ϕ)\\ v(t)=-Aωsin(ωt+ϕ)\\ \\ Let\quad n=integer,\quad A=0.5,\quad ω=2.\\ \\ Given\quad initial\quad position\quad (0,\quad 0.25)\quad and\quad initial\quad velocity\quad (0,\quad 1),\quad find\quad ϕ.\\ \\ x(t)=0.5cos(2t+ϕ)\\ 0.25=0.5cos(ϕ)\\ ϕ=±1.0471975512+2πn\\ \\...
  24. R

    Questions about finding position, velocity, acceleration related

    A stone is thrown upward from the top of a 20 m high cliff at an angle of 25 degrees. The stone has an initial velocity of 15 m/s. Make the BASE of the cliff the origin. (a) Write out the position, velocity, and acceleration vectors for the stone. (b) What is the magnitude of the velocity of the...
  25. C

    Accepting a position not related to physics

    I graduated with a BA in physics in December 2012 in the United States and am currently searching for a job. I have a connection at a company that manufactures bearings, seals, and rings among other things for a variety of industries. Some examples of these industries are: medical systems...
  26. K

    Determining on what type of Motion to use on a Position Time Graph?

    I was given a table to plot on to a position time graph, but how would I know what type of motion to use? A curve or straight line? Here is the table T---P 0---0.0 4---2.0 6---3.0 10---4.0 15---5.0 16---5.0 18---4.4 22---3.2 26---2.0 28---1.4 33---0.0
  27. A

    Throttle Position sensor Working

    Almost all the cars now use an Electronic Throttle Body for Controlling airflow into the engine. In order to make the system Fail-safe, manufacturers use two Potentiometers for the throttle position sensor feedback. My doubt is regarding the method used for tapping output from both the...
  28. A

    Calculate electric field at position x given ρ and thickness d?

    Calculate electric field at position x given ρ and thickness d?? Homework Statement Two large uniformly charged slabs, I and II, are stacked together as shown in the picture. Suppose the thickness of each slab is d= 0.2 μm. The volume charge densities in the negatively charged slab (I)...
  29. J

    Particle in plane, find position vector

    A particle of mass m moves in the x-y plane; its acceleration in m/s^2 is given by the expression ->a = −6iˆ for t ≥ 0 secs . At t = 0 secs, the object is at the point (x(sub 0), y(sub 0) = (36,0); coordinates are in meters. At t = 4 secs , the object is at the point x(sub 0), y(sub 0) = (36...
  30. D

    Velocity in relation to position

    A hot-air balloon has just lifted off and is rising at the constant rate of 1.8 . Suddenly one of the passengers realizes she has left her camera on the ground. A friend picks it up and tosses it straight upward. If the passenger is 3.1 above her friend when the camera is tossed, what is the...
  31. M

    Confusions about Position Independent Code

    Hello! I was reading this excellent article about position independent code and it's implementation for shared libraries. I'm still confused about one part though. My current understanding is that the offset between the code section and data section is known at compile time. Since this offset...
  32. Astrum

    Whirling Rope - Find the Tension at Position r

    Homework Statement A uniform rope of mass M and length L is pivoted at on point and whirls with uniform velocity ω What is the tension at the rope at r from the pivot point? Neglect gravity. Homework Equations The Attempt at a Solution Centripetal force at r is given by -mr...
  33. Sneakatone

    Finding position vectors of x y z in meters

    Air traffic controllers usually describe the position of an aircraft relative to the airport by altitude horizontal distance and bearing . suppose an air craft altitude 1450 m , distance 24 km , and bearing 18.0 degrees east of north. what are the x,y,z components in meters of the position...
  34. M

    Vector Proof Question for position of particle

    Homework Statement If ~r, ~v and ~a denote the position, velocity and acceleration of a particle, prove that Homework Equations (d/dt)[ a * ( v x r)] = (da/dt) * (v x r) "*" is a dot product "x" is a cross product The Attempt at a Solution I didn't really get that far. The...
  35. stripes

    Index of refraction, position dependent

    Homework Statement We know, for constant n, \frac{\partial L}{\partial y} = \frac{d}{dx} (\frac{\partial L}{\partial y'}), where we define L as being the optical light path length, and y' is the derivative of y with respect to x, and L = L(y, y') = n \sqrt{1 + y' ^{2}}. However...
  36. B

    Brushless DC Rotor Position Question

    Hi. I am curious about ways to sense the position of a rotor in a BLDC motor. I am familiar with hall sensors and back emf but am wondering if there are other ways to find the position of a rotor maybe more accurately. I had an idea about using a laser and a photoresistor around the...
  37. C

    Position vector R of a particle moving x-y plane

    Hello, new to these forums! I'm working on my UPI homework, and I just want to verify if I'm doing something correctly. The problem: The position vector r of a particle moving in the x - y plane given by r = (2t^3)i + (6-7t^4)j, where r is in meters and t is in seconds. Calculate r v a...
  38. N

    Noncommuting position variables due to quantum gravity

    I've read that if one wants to quantize gravity , there must be a smallest length scale " The Planck length " . If I want to measure the position of a point particle then in conventional Quantum mechanics I'll find it at the point $(x,y,z)$ at some-time $t$ with an arbitrary momentum but this...
  39. A

    Optics: Finding the wave equation given position and amplitude information

    A harmonic wave traveling in +x-direction has, at t = 0, a displacement of 13 units at x = 0 and a displacement of -7.5 units at x = 3λ/4. Write the equation for the wave at t = 0. Homework Equations The equation for a harmonic wave is r = asin(kx-vt+θ) a being the amplitude k...
  40. F

    Neutral wire position - Distribution system

    looking for standards & guidelines on Neutral Wire for distribution system, especially Neutral Up or Neutral High (neutral on top of the phase conductors), advantages & dis-advantages of it.
  41. L

    TISE in the position representation- basic question

    We were told in lectures that the time independent Schrodinger equation can be applied to wavefunctions, i.e. \frac{hbar^2}{2m}\frac{d^2U}{dx^2}+V(x)U=EU where U is the wavefunction bra x ket psi. I don't understand why this is valid, as wavefunctions are probability amplitudes, and operators...
  42. D

    MHB Angular Velocity for Constant Separation Distance

    Determine the required angular velocity $\omega$ of the relative position vector in order to maintain a constant separation distance $r_0$ for two equal masses. What equations are needed for this?
  43. J

    Matrix Mechanics position and momentum operator

    Homework Statement Stationary states are related by 1/m*pij = Ei-Ej/(i*hbar) *xij where pij = ∫ψi(x)*p*ψj (x) and similarly for xij Homework Equations Classical correspondence for equation of motion is d<x>/t = <p>/m Schrodinger equation Ehrenfest Theorem Fourier Transform The...
  44. W

    Finding the position directly behind a player

    I'm attempting SCIENCE by using math that I have never used before, nor do I understand (despite reading numerous articles, watching all of the khanacademy videos, etc etc) I'm attempting to use trig to locate a point directly behind another player in Minecraft. I've read through these...
  45. M

    QM Interpretation & Young's Exp: Electron Position Defined?

    According to the Copenhagen Interpretation, and considering Young's double slit experiment: Is what interferes the mathematical wave function flowing out the two slits but the electron itself takes a well defined path? Anyhow, I need a clearer idea about the position definition or...
  46. S

    Expectation of Position of a Harmonic Oscillator

    Hey, My question is on determing the expectation value of position of the Harmonic Oscillator using raising and lowering operators, the question is part d) below: I have determined the position operator to be: \hat{x}=\sqrt{\frac{\hbar}{2m\omega}}(a+a^{\dagger}) and so the...
  47. D

    MHB Position of Particle in a Circular Path: Solution

    Relatively easy question but I haven't done anything like this in awhile. $$ \mathbf{r}(t) = \hat{\mathbf{x}}R\cos(\omega t) + \hat{\mathbf{y}}R\sin(\omega t) $$ The particle moves in a circle so I want to show that the position is given by the above. I know at $t = 0$ the particle is on the...
  48. M

    Rate of Change Problem with Clock Hand Position

    Homework Statement "On a certain clock, the minute hand is 8 cm long and the hour hand is 6 cm long. How fast, in cm/min, is the distance between the tips of the hands changing at 9 am?" Homework Equations The Attempt at a Solution I should be able to transform this somewhat...
  49. B

    What is the Curl of the Position Vector?

    Homework Statement compute the curl of: \vec{r} and \frac{\vec{r}}{r^3}Homework Equations \vec{r}=x\hat{x}+y\hat{y}+z\hat{z} r^3=(x^2+y^2+z^2)^\frac{3}{2} The Attempt at a Solution I figured out that the curl of \vec{r} = 0 as my book says it should be... however...I also need to prove...
  50. T

    Find time, given acceleration as a function of position.

    Hello guys, the following problem I've had is from Beer and Johnston, Dynamics: Homework Statement At a distance R above the Earth's surface, a particle at rest is let go. Given the gravitational acceleration: a =-g\frac{R^2}{r^2} where r is the distance from the center of the Earth to the...
Back
Top