Position Definition and 1000 Threads

Hi, I am wondering how to describe a position of our solar system to some other extraterrestrial intelligence in some distant galaxy to find us? Is it possible or not? i mean if such guidance exist for any galaxy or they have to track back movement of your probe or spaceship etc. and some...

Homework Statement http://img824.imageshack.us/img824/6466/31231242.png http://img835.imageshack.us/img835/5220/76022234.png It's a free fall problem and I have to calculate a = g Homework Equations g = (2*(d-(vi * t)))/t^2 g = (2d)/t^2 The Attempt at a Solution I've made a...

Homework Statement A motion detector transmits a click which is reflected off of a moving car. The echo is received by the motion detector after .0026 seconds. the motion detector sends out a second click .1 seconds after the first click. The echo for the seconds click is received after...

How can you let Initial position and initioal velocity be equal to zero? I understand that it will be zero at time = 0, but as time goes on from 1, 2 , 3 , 4 won't it change? I underlined that it in read in the picture?

Homework Statement A binary star system consists of a star P and a star Q, of mass 4.0 x 10^10 kg and 2.0 x 10^10 kg respectively, separated 6.3 x 10^9 m apart. Star P and Star Q move in circular orbits with their centers at the center of mass which remains at rest. Find the position of...

What is the difference between position time graph, velocity time graph and acceleration time graph and how would each of them look like when drawn?

Homework Statement The diagram (http://i83.photobucket.com/albums/j282/missingyoub4urgone/Physicsyahoohelp.png) tracks the location of an object moving in a straight line along the x-axis. When is the object (a) farthest from the origin, (b) at rest for an instant, (c) in the midst of being at...

Homework Statement I can't figure out part two to a problem. The first part asked us to find the displacement, but I'll let you read for yourselves: Part 1: A cyclist maintains a constant velocity of 5.3 m/s headed away from point A. At some initial time, the cyclist is 259 m from point...

Homework Statement The position v. time graph for a certain object moving along the x-axis is shown. I don't have the graph. Bu I have the points. (0,-2), (1,9), (4,4), (6,4), (8,-4), (9,0) The object's initial position is -2m. Find the instantaneous velocity at ... (m/s) a.) 0.5s...

Hello, As a concrete model to refer to, I'll work with the one-particle system in a potential box with infinite edges. Inside the box is a potential barrier of height V. Let's say we've measured the energy at one moment to be E < V. The probability of measuring the particle inside the barrier...

Homework Statement A particle's trajectory is described by x=((1/2)*(t^3)-2t^2)m and y=((1/2)*(t^2)-2t)m, where t is in s. a) What are the particle's position and speed at t=0s and t=4s? b) What is the particle's direction of motion, measured as an angle from the x-axis, at t=0s and...

Hello everybody, I'm working on a project and I want to verify a few theories I have. I'm unfamiliar with equipment for taking these types of measurements, so I wanted a little bit of help on this. Basically a bb is fired from an airsoft gun (350-550 fps), and I want to find the...

two particle of mass, find distance of equilibrium position? need a hint to start question, really appreciate

Homework Statement An electric point charge of Q1 = 5.23 nC is placed at the origin of the real axis. Another point charge of Q2 = 1.89 nC is placed at a position of p = 2.63 m on the real axis. At which position can a third point charge of q = -2.62 nC be placed so that the net...

Homework Statement The acceleration of a particle is given by a(t)= - 2.1 m/s2 + (3.1 m/s3)t Find the initial velocity v0 such that the particle will have the same x-coordinate at time t=3.96 as it had at t=0. What x-coordinate will the particle have at time t=3.96 Homework...

I have read that, in QFT, unlike QM, there is no position probability density function because position is not considered an observable. Then how is a position measurement represented/modeled in QFT? As always, thanks in advance.

Confused about a simple thing... For a common balance, since both arms have equal weight, what causes the pole to choose a horizontal position? Shouldnt it be stable in any other position as the torque around the centre is zero for any other position too?

The position of an object is given by x=At+Bt^2, where x is in meters and t is in seconds. a)What are the units of A? (express answers in terms of m and s) b)What are the units of B? (express answers in terms of m and s) I know this may sound silly, but I really don't understand what the...

Hey, everyone. I'm preparing to apply for a undergrad. research position. I have the link about the research topic: http://electron.physics.buffalo.edu/hzeng/ For those who did not goto the link, its about nano-scale magnetism. I want to be part of the research project because magnetism is one...

I just started taking a Quantum Mechanics course at my university (only 3 days into it) and some of the topics got me thinking about stuff. Namely, about "particles". I searched on Physics Forums and found some other posts pertaining to my question, but a lot of the responses referenced topics...

Hello, Can someone here settle a debate for me? A friend of mine said that if you hold two neodymium magnets 1" or so apart from each other with attracting ends (N-S) facing each other for prolonged periods of time (years and years), nothing will happen to the magnetic field. I stated...

Homework Statement Given the graph in the uploaded screenshot, what is the bicyclist's velocity at t=10s?Homework Equations I have been trying to do a slope equation? Rise/run. The Attempt at a Solution Tried to do slope equation. Looks like 75/10, which would be 7.5, but that answer is...

Homework Statement A perfectly spherical ball is launched horizontally with a linear velocity of 9.9 m/s and an angular velocity (perpendicular to its trajectory) of 4.1 m/s. The ball's mass is 5.0g. (Diagram for explanation of coordinate system)...

How do you "observe" the position of an electron? Do you use x-rays? If so, what happens when you hit the orbital of a given atom with x-rays? Will it just accelerate the electron(s) out of the orbital? Also, how can you then infer the position the electron had initially occupied? Do you just...

So I had an interview with a top electronics company last Friday. It came down to me, and one other candidate. When I was flown out to the east coast, and met with my interviewers, I discovered that my competition had taken a position elsewhere! I proceeded through two interviews...

Hi, I have a bunch of text documents, each of which contains (among other information) the x- and y-positions of 1,000 different 2-D disks at some given time. I want to write a code in C which takes each text document and outputs a visualization of the system at that instant in time. The...

I'm applying for a tutoring position at my school. I already passed the pre-interview and took the test (basic algebra). I did not pass the algebra test, because it was all stuff I haven't done in a few years. However I have a retest Monday, and this weekend to study. She wouldn't let me look...

Hi, I am looking for a sensor/ detector (A) which could perform the following: constrain: transmitter/ receiver (B) size must be small so that it can be inserted in human bone to be detected later, diameter 3mm X 6mm length is preferred, however, a bigger size can be consider as well...

Homework Statement Two identical uniform rectangular flat planks with sides a and b are glued together to form a T-shaped object. Specify the position of the center of mass. State any theorems you use in order to arrive at your conclusion. See the attempted solution for a diagram. :) The...

Homework Statement Consider the plot below describing the acceleration of a particle along a straight line with an initial position of −15 m and an initial velocity of −3 m/s. A) What is the velocity at 5 s? Answer in units of m/s. B) What is the position at 5 s? Answer in units of...

Hello everyone, But I watched a video on youtube that showed another way.That video suggested a pic like this Is the top pic wrong and my final pic right! Thanks! :smile:

Homework Statement When will the velocity be zero? t is in minutes s is in metres Homework Equations s = 4t^3 - 8t^2 + t - 50 The Attempt at a Solution I came up with the velocity equation by taking the derivative of function s. I came up with the acceleration...

To prove: Commutator of the Hamiltonian with Position: i have been trying to solve, but i am getting a factor of 2 in the denominator carried from p2/2m Commutator of the Hamiltonian with Momentum: i am not able to proceed at all... Kindly help.. :(

Homework Statement Consider the plot below describing the acceleration of a particle along a straight line with an initial position of −15 m and an initial velocity of −3 m/s. A. What is the velocity at 5 s? Answer in units of m/s. B. What is the position at 5 s? Answer in units of...

Hello, This isn't exactly homework, but I am attempting to learn quantum mechanics on my own and was wondering if this forum could be used for guidance in that direction. What I want to do is familiarize myself, as accurately as I can, with the specific mathematical picture of the universe...

Homework Statement What I would like to do is find the minimum velocity needed to launch a projectile from point A to B when B is not at the same height as A. I keep finding myself stuck with two unknowns (initial speed and release angle) and I am not sure how to resolve them. If the problem...

Hi So Heres the Question:- A player throws a ball upwards with an initial speed of 29.4 m s–1. (a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ? (c) Choose the x = 0...

Im still on high school so I don't know where this question belongs to, I don't know even what is the exact subject of this question, so I would like you more experienced members to help me understand what exactly I am asking and where I can find information about it: "In an empty universe...

I'm wondering if anyone here has been so moved by events following the 3/11 earquake, that their position has been changed in regard to nuclear power. First, please let us know your position before March of this year. Second, let us know if you position has changed, either for, or against the...

Hello everyone, after examining the double slit experiment and pondering for several days, I came to the conclusion that the notion of superpositions is a bit of a "leap of faith." "Evidence" for superpositions is said to be the double slit experiment, but could the Idea of superpositions be...

In the temperate latitudes of the northern hemisphere, the sun is due south when it reaches the highest point in the sky (see for example http://www.solarplots.info/pages/definitions.aspx" ). What about latitudes between the Tropic of Cancer and the equator? Is the sun due north when it reaches...

I am working on a project where I have a ball-screw type linear actuator being driven by a 24V variable speed DC motor. There is another 24V DC motor that drivers a pinion and ring-gear. The linear actuator controls the system's elevation and the ring gear controls the traverse. I would...

the position vector of the particle is given by s=e^-2ti+sin(2t)j+5t^k calculate its velocity and acceleration at t=0 to get the velocity i differentiated with respect to t and substituted in t=0, giving me velocity=-2i+2j and that's the same as the answer given but I am not sure how to get...

I know that a constant acceleration would mean that the position is changing, and the position would be moving, and the speed would be changing, (increasing). I would eliminate the far right two choices because the position is changing on them and they are moving at a constant speed, and a...

I am doing my Extended essay about the maths involved in calculating your position using the GPS. I am reading a very complete book, but the maths are sometimes too hard or not enough deeply explained for my level and I am struggling to follow some parts. Here I post one page of the book where...

Hi, {First off I should share my ultimate goal, which is to have a position function of time of several bodies, let's say in a solar system, so that the position of each body and the acceleration due to gravity on all the other bodies in the system are given at any time t. Although Kepler's...

Hi, {First off I should share my ultimate goal, which is to have a position function of time of several bodies, let's say in a solar system, so that the position of each body and the acceleration due to gravity on all the other bodies in the system are given at any time t. Although Kepler's...

Homework Statement Heisenberg's uncertainty principle states that you cannot simultaneously know the position and momentum of an object. In this video link, a laser is aimed through a slot and projected onto a wall. As the slot gets narrower, the projection also gets narrower. Eventually...

Homework Statement θ is an angle in standard position with domain 0° <θ< 360° and cot θ = . Find all possible values of θ Homework Equations ? The Attempt at a Solution ?

Hi all, I am trying to code a simulation that pins two bodies against each other and animates their motion. I am using Sun and Earth as example, with preset positions and velocities, and Newtons Law of Universal Gravitation formula. It all works quite alright, up until I have decided to link...