Position Definition and 1000 Threads

Hey If I have a InAs Wurtzite structure, and now the a and c parameter from tables. How can i calculate the distance between (1 0 3/2)_sur layers? (in surface coordinates) I need it to find the angle of reflection, for a (1 0 3/2) WZ InAs peak. Is it just so simple? (1 0 3/2)_sur =...

Suppose a helicopter is stationary at certain height And a observer sees it from ground. But after one day the observer again sees the stationary helicopter than will it appear To be at the same Position Or somewhere else

Okay this seems like it should be simple but I'm stuck. A particle moves from point A to point B in one dimension. The velocity of the particle changes with position according to some formula V = V(x). How long does it take for the particle to get from point A to point B? If I could write...

I'd like to show that if there exists some operator \overset {\wedge}{x} which satisfies \overset {-}{x} = <\psi|\overset {\wedge}{x}|\psi> , \overset {\wedge}{x}|x> = x|x> be correct. \overset {-}{x} = \int <\psi|x> (\int<x|\overset {\wedge}{x}|x'><x'|\psi> dx')dx = \int <\psi|x>...

EDIT: I figured it out by looking at this link pages 65-66. Thanks for looking though! http://www.bfasta.net/assets/files/departments/science/ismith/Phys%20446/Phys%20446%20Information/HSU/Chapter%204%20Acceleration.pdf Homework Statement Recently I just did a physics lab for kinematics in...

A watermelon seed has the following coordinates: x = -6.6 m, y = 2.2 m, and z = 0 m. Find its position vector as (a) a magnitude and (b) an angle relative to the positive direction of the x axis. If the seed is moved to the xyz coordinates (8.2 m, 0 m, 0 m), what is its displacement as (c) a...

I've noticed on a/c with only two wing mounted engines that they tend to be closer to the fuselage than the wing tip. There must be some reason for this, and so I guess my question is why? Does having them farther out on the wing create too much stress? I would assume if a/c manufacturers could...

Homework Statement "A particle moves in the horizontal plane that contains the perpendicular unit vectors i and j. Initially it is at the origin and has velocity 18ims^-1. After accelerating for 10 seconds its velocity is (30i + 8j)ms^-1. Assume that the acceleration of the particle is...

A vertical cylindrical container contains some helium gas that is in thermodynamic equilibrium with the surroundings. The gas is confined by a movable heavy piston. the piston is slowly elevated a distance H from its equilibrium position and then kept in the elevated position long enough for the...

Would people on the north pole see a totally different set of stars than people standing on the south pole..? Would the Big Dipper be visible from the South Pole..? Would people living on the equator see even a different set of stars..?

Homework Statement Spring and Hanging Mass A block of mass 4 kg hangs vertically from a spring with constant k = 100 N/m which is attached to the ceiling and initially is not stretched or compressed. The block is initially held at rest by an external force. The block is then released and falls...

significance of commutation of operators? how do u show that the position and momentum operators do not commute?

Hello guys I am wondering how to find a research position as an undergraduate. Typically, only third year student will be able to find something "real" research job in the summer. Does this mean that it's not possible to do research or maybe assisting research during the regular school time...

Homework Statement A hot-air balloonist, rising vertically with a constant velocity of magnitude v = 5.00m/s , releases a sandbag at an instant when the balloon is a height v = 40.0m above the ground . After it is released, the sandbag is in free fall. A: Compute the position and velocity of...

I need a list of type Ia supernova with redshifts, Distance Modulus, Distance modulus error, and position in galactic coordinates, but I havn't been able to find one that has all of that information (I have found several with some of the information, but not all of it). Does anyone know where I...

Im interested in knowing what kind of sensors are used and it's overall execution, thanks.

ok so here is the quesiton.. An object is loacted 3.5 cm from the optical centre of a lens. The lense produces an image of magnification that is +0.667 the size of the object a) is this lens a diverging or converging lens? explain b) Find the position of the image and the focal length...

Hi, I'm trying to measure how far a rod that passes through a tube is offset from the center. Assume that the axis of the tube runs parallel to that of the rod. I can only access the interior of the tube from above (it hangs vertically), and the access hole I have is smaller than the radius...

Homework Statement a regular hexagon OPQRST has its vertices at O ( the origin) and points P,Q,R, S,T with position vector p,q,r,s,t respectively. The point U with position vector u is the midpoint of the line segment OP, and SU meets OR at the point V please see attached diagem I need...

Velocity, displacement and position time graph help! cyclist road east for 1.0x10^2 m with a constant velocity of 25 m/s she then accelerates down a hill and 5s later reached the bottom of the hill with a velocity of 50m/s a) how long did the cyclist ride before reaching the hill? B)what is...

are observables only those quantities which commute with system's Hamiltonian ?

I've been scratching my head over this one. I'm trying to find a system of equations to solve for points R and S. The known parameters are: Point Q, tangent vector t and the axis vector a. The following vectors are perpendicular to each other: a,d a,b b,c c,t d,t The other known...

Lenses - magnification, position, focal length help! ok so here is the quesiton.. An object is loacted 3.5 cm from the optical centre of a lens. The lense produces an image of magnification that is +0.667 the size of the object a) is this lens a diverging or converging lens? explain b)...

Homework Statement A small positively charged sphere of mass m is attached to a very large positively charged vertical plate by a string and hangs due to gravity. The charge density on the plate, σ, is uniform. a) Calculate the equilibrium position of the ball as a function of the (uniformly...

A v-t graph depicts an object's movement along the positive x-axis from 0-10 seconds. If the object at position x=xofc on the line at t= 6 seconds (depicted as point C on the graph), find its position at t= 10 seconds. It appears the question is not referring to total displacement but just...

Before going off to college, I'd really like to do some physics-related research at a local university. I'm really excited about the idea of physics, and I can do math very proficiently. The problem is, I have no prior experience in research other than labs done in high school science classes...

Hi I would like to know if I have a system of coupled harmonic oscillators whether the standard position operator for an uncoupled oscillator is valid, i.e. x_i = \frac{1}{\sqrt{2}} (a_i+a_i^\dagger)? where i labels the ions. To give some context I am looking at a problem involving a...

Homework Statement This circuit shows a 10Kohm potentiomiter with a 5Kohm load. determine the position of the slider on the 'pot' when the voltage acreoss points 'xx' is 3V ok so the 10K resistor is a potentiometer which is a variable resistor, so what they are asking when they say...

Homework Statement You walk to the corner store after school to buy a carton of milk before going home. The store is 750 m south of the schoo, and your house is 625 m north of the school. What is your net displacement. Homework Equations dT=d1+d2 formula for displacement The...

I am about to graduate with a bachelors in Mechanical Engineering with three possible paths: - A confirmed offer as Design Engineering Trainee at a small design company which takes outsourced design projects related to industrial design and automotive - A prospective offer from a...

Hi physicists, How can two atomic-scale particles interact through gravitation (Gm1m2/r^2) or any other force that is a function of r if r isn't know with complete certainty. Is it that the force itself also comprises uncertainty in its value? Thanks

Hi! I was just wondering if anyone knows where I can find a software/algorithm that can give me the postion of the sun and the moon in ECEF coordinates? If not, do you have any clues to how I might start building one? I am an engeneering student, so I don't have a lot of knowlegde about...

How do we experimentally determine the position of an electron that is not bound to any atom and far away from all other influences including electromagnetic and gravitational fields? [Edit: what would the apparatus be?]

according the principle of superposition, a wave with a certain amplitude superposed with a similar wave will yield a wave with 4 times the amount of energy. This would be double the combined energy of the original 2 waves. Assuming 2 point wave sources are perfectly in phase; and there is no...

Bar collision with ground Homework Statement A uniform bar of mass m and length l has no angular velocity when the extremity A hits the ground without bouncing. If the angle α is 30º, what is the magnitude of v1, so that the bar rotates, around A, until it immobilizes on the vertical position...

Homework Statement I'm not sure if my graph for this problem is correct... I've attached it below, can someone please help me? The problem is: In heavy rush-hour traffic you drive in a straight line at 12 m/s for 1.5 minutes, then you have to stop for 3.5 minutes, and finally you drive at...

Homework Statement Use the following Bronsted-Lowry reaction to answer the following question: HMo(aq) + H2O(l) ⇔ H3O+(aq) + Mo–(aq) The best description of this equilibrium is that: A. Products are favoured. B. Reactants are favoured. C. The reaction is quantitative. D. The reaction is non...

Homework Statement Plot the position vs time graph of an object attached to a spring. m = 0.5 kg k = 60 N/m x[0] = 3 m v[0] = 4 m/s Homework Equations d²x/dt² + (k/m)*x = 0 The Attempt at a Solution I solved the differential equation using DSolve and plotted the resulting...

If you have a cylindrical permanent magnet with a voice coil around it, sound moving the voice coil a small distance back and forth along the length of the bar magnet will produce an RMS voltage across the voice coil; but not very much RMS voltage if the voice coil is in the center of the...

Homework Statement Assume speed of 435g football is known with 1mm/s uncertainty. What is the minimum uncertainty in its position? Homework Equations I'm not quite sure... I know p=mv, and I know that Heisenberg's uncertainty principle states that certain parameters of quantum...

I am new to the topic of special relativity. Having read a bit of Feynman and googling for answers I am still a bit lost. While I have an aptitude for logic, it does not extend quickly into physics or maths. So quite likely I am barking up the wrong tree and about to demonstrate my ignorance but...

Homework Statement A potential energy function is given by U(x) = 4x^2 and I found the total energy to be 7 J. They ask: Graph position vs. time and kinetic energy vs. time using this information and assume that the particle has an initial position of 0. The Attempt at a Solution I got the...

Hi everyone, I am having trouble finding the answer to a homework problem. I don't seem to understand what the question is exactly asking for. The problem is: find the path of a particle with an initial position 10er + 1.0eϴ and an initial velocity 0.1er + 0.8eϴ

Hi, I am making a program with the simulation software Breve. It codes in Python or in Steve (their own language). In my simulation, spherical particle with random radius are being spawned at random position into a little zone. My problem is that those particle cannot be superposed. I don't know...

I've been curious for some time about the concept of super position. my introduction to the idea was through the schrodingers cat paradox, which i assume most know, so i will stick with this example. is it not correct to assume super position is a concept to resolve the perceptual limitations of...

I'm trying to work out the mathematics of this for a school project. Say you have 4 beacons arranged in a square (I think you only need 3, actually) at known positions relative to one another. Now say you are in a random position within this square, at a random height, and at a random...

Hey, I have been churning the idea of Dirac notation around in my head and I am thinking about the position and momentum basis representation of a wavefunction in a Hilbert space. Wikipedia mentions the following in the article 'Bra-ket notation' under the heading 'Position-space wave...

Hello everyone. First of all, thank you for any help you can provide. The essence of the problem is this. I am given the linear and angular velocity of an object at a given moment in time. Data looks like this: Time(s): Linear velocity (m/s) Angular velocity(rad/s) 10.313...

I'm looking at a book on meteor calculations involving at two Earth stations, A and B. The computations for A are given, and the same for B. I would like to know a reference for equations 12, 13, and 14. Even a derivation. I find figure 4 a bit puzzling. The text uses lower case phi, a...

Homework Statement A position vector of a particle at a time t is r=icost +jsint +kt ; show the speed and the magnitude of the acceleration is constant. Describe the motion. Homework Equations v = dr/dt a = dv/dt The Attempt at a Solution Could someone let me know if I am doing...