Position Definition and 1000 Threads

Hello Everyone, I am working on building a simple robot. Basically, I have a small platform with two motorized wheels and rotary encoders on the edges. So, using the rotary encoders I can estimate the velocity of the two wheels. I then need to use this information to calculate the path...

What is a position vector? Is their any difference between the position vector and position? Isnt position of a point supposed to represent its direction in Cartesian plane as well(Positive quadrants , negative quadrants). So why two different terms?

Homework Statement Hey guys. Basically I have a wavefunction that looks like this http://imageshack.com/a/img843/3691/22r3.jpg I have to find: (a) The normalization constant N, of course by normalizing it (b) Find <x> and <x^2> and use this to find Δx. Homework Equations I'm just...

Homework Statement The graph of acceleration versus time for an object in linear motion. Assuming the object starts from rest at the origin at t = 0, find the velocity and position of the object at times t = 1 through 10 seconds. Homework Equations ##v=v_i + at##The Attempt at a Solution I...

Homework Statement An object of mass ##5##kg is released from rest ##1000##m above the ground and allowed to fall under the influence of gravity. Assuming the force due to air resistance is proportional to the velocity of the object with proportionality constant ##b=50##N-sec/m, determine the...

i was reading brian cox's book about *the quantum universe * and he said something interesting if for instance we know that a particle exists in ΔX , then this delta has to be less than one wavelength * he did it with clocks * to know the probability of its existence somewhere else in the...

Homework Statement A cannon shoots a ball at an angle θ above the horizontal ground. Neglecting air resistance use Newton's second law to find the ball's position as a function of time. (Use the axes with x measured horizontally and y vertically.) Let r(t) denote the balls distance from the...

Homework Statement A particle initially located at the origin has an acceleration of vector a = 5.00j m/s2 and an initial velocity of vector v i = 8.00i m/s. a)Find the vector position at any time t (where t is measured in seconds). (Use the following as necessary: t.) Find the vector...

Homework Statement The distance traveled by an airplane flying from San Francisco International airport (SFO) to San Jose International (SJC) is 30 nautical miles 36° south of east. Flying from SJC to Tracy, the plane's displacement is 36 nautical miles 52° east of north. What is Tracy's...

Homework Statement An object has a position given by r-> = [2.0 m + (1.00 m/s)t] i + [3.0m−(5.00 m/s2)t2] j, where all quantities are in SI units. What is the magnitude of the acceleration of the object at time t = 2.00 s? Homework Equations All I am thinking here is that I can find...

I keep coming across the claim that it is a consequence of the Schrodinger dynamics, that even if one postulates wave-function-collapse, so that the wave-function for a particle is entirely confined within some small region at the moment of collapse, an instant later the wave-function will have...

We are given a velocity vs. time graph. It starts at 15 m/s at t=0 and goes to -10m/s at t=4 then it goes from -10m/s at t=4 to 15m/s at t=10 and we are told to find the postion after t=10 I first found the slope of the first segment which was -6.25. so I did ∫-6.25t+15 dt from 0 to 4 and...

im confused with finding the max velocity , acceleration, and position. Usually in these types of problems I'm given a function, and an interval and have to find the max acceleration or velocity. Sometimes a negative number comes up which is greater in magnitude than the other numbers...

Homework Statement Hi guys, I've not started a course on QM yet, but we are currently learning the maths used in QM. Show, by taking the trace of both sides show that finite dimensional matrix representations of the momentum operator p and the position operator x which satisfy [p, x] =...

Hello PF members! First of all, let me start off my post by admitting that I have created a duplicate account. My original account was banned for a good reason. Now, I am studying physics. More specifically, I'm studying relativity. I trust that you all will help me understand what...

Picture of the system (it's sideways): http://tinypic.com/r/28qq4pi/5 Consider the mass from the spring in the figure. Let m=1, k=1, and g=9.81. Assume that x and y are zero when the 2 springs are unstretched. Assume the system starts from rest with the first spring extended by an amount...

Homework Statement You are consulting for an elevator company. During a safety test, technicians created the following graph of the velocity of the elevator versus time; you have been asked to interpret the graph. Unfortunately, you are told that the technician who printed the graph has made...

Homework Statement Homework Equations Coulomb's Law The Attempt at a Solution Here are 2 different possibilities I drew that I think will have the x component vectors and y component vectors cancel out, but I think there may be some other positions as well. ##\textbf{F}_x = k_e...

When given an image of a scene of something like a hallway or road (looking down this hallway or road) a vanishing point can be determined. Also, the points on the image must lie on a certain line in the real world environment given by: x_{im} = f\frac{X}{Z} and y_{im} = f\frac{Y}{Z} where...

The problem asked me to prove the following (where \vec{r}, \vec{v}, \vec{a} are the position, velocity and acceleration vectors of a moving particle): \frac{d}{dt} [\vec{a} \cdot (\vec{v} \times \vec{r})] = \dot{\vec{a}} \cdot (\vec{v} \times \vec{r}) I already did so, but my question...

I'm given the position vector as a function of time for a particle (b, c and ω are constants): \vec{r(t)} = \hat{x} b \cos(ωt) + \hat{y} c \sin(ωt) To obtain it's velocity i differentiate \vec{r(t)} with respect to time and i obtain: \vec{v(t)} = -\hat{x} ωb \sin(ωt) + \hat{y} ωc...

Homework Statement You are consulting for an elevator company. During a safety test, technicians created the following graph of the velocity of the elevator versus time; you have been asked to interpret the graph. Unfortunately, you are told that the technician who printed the graph has made...

How do you solve the Kepler Problem for a 2-body system where m1<<m2 with a given velocity and position vector resulting in a new velocity and position for a certain time interval?

momentum, position vector dot (scalar) product "action" Hello, I was playing with single mass point classical mechanics, when I realized that the dot product of the position vector and momentum vector, p.r , has action dimension. Furthermore, its time derivative, d/dt(p.r) = F.r + p.v, has...

I am trying to develop a graphical, interactive simulation of a wave function in position space, given an arbitrary potential. It works great, but as a final touch, I would like the user to be able to collapse the wave function, either by measuring its position or its momentum. My problem is...

Homework Statement The graph is of a runner- time(min) is the x position(x1000 m) is the y these are the points 0,0 10,3 20,3.5 30,4.5 The question is- For the time interval between 10 min and 20 min, what is the runner’s displacement? Answer in units of m Homework...

where are the holes in the p-type semiconductor situated? in the conduction band or the valence band? i am talking about the holes formed because of the acceptor impurities, not the thermally generated ones.

I would like to have a Star orbiting a Schwarzschild Black Hole if the the velocity and position vectors in the galaxy are given. The only thing that comes to mind is the Newtonian method. The velocity and position vectors of the Star are: v = {v_x, v_y, v_z) r = {x, y, z) where (no...

Hey guys, so I have a quick question about position - time graphs, so without using calculus for let's just say a particle moving west along a horizontal straight line every 0.10 s and the displacement is 0.022, 0.032, 0.042, etc. Well the displacement from t = 0 aren't really good numbers...

The vector equations of two lines are given below $r_1=\pmatrix {5 \\ 1}+2\pmatrix {3 \\ -2}$, $r_2=\pmatrix {-2 \\ 2}+t\pmatrix {4 \\ 1}$ The lines intersect at the point P. Find the position vector of P this being in form of r=a+tb where a is the the position vector and b is the...

What is the evidence for Hawking's statement here: "After giving a brief historical background on relativistic physics and cosmology, Hawking discussed the idea of a repeating Big Bang. He noted that in the 1980s, he and physicist Roger Penrose proved the universe could not “bounce” when it...

Homework Statement https://www.physicsforums.com/attachment.php?attachmentid=60570&stc=1&d=1375128608 Thew circuit shows a 10KΩ potentiometer with a 5KΩ load. determine the position of the slider on the 'pot' when tthe voltage across points 'XX' is 3V Homework Equations The...

In molecules like SCl4 lone pair occupy equitorial position.But, in IF5 lone pair occupy axial position.Why can't the lone pair in SCl4 occupy axial position?

I've been studying a version of the finite element method. The author of a paper I was reading refers to the partial derivative of total elastic energy wrt position, partial derivative of surfacic energy wrt position, and partial derivative of strain wrt position. Does anyone know of a good...

\vec{r}_a is a positional vector from reference frame a. What is the position of same point from reference frame b ? If required, assume position of origin of frame a is \vec{m} and unit point (i.e. \langle 1,1,1\rangle_a ) is \vec{n} from reference frame b. I am studying Kleppner and Kolenkow...

what does position entangled mean (physically)? The below is an attempt to understand position entanglement. It may require a lot of corrections and modifications. Look forward to your responses. A photon (A) would have a probability distribution, so would it's entangled twin/photon (B). The...

How can I draw the position time graph for uniform acceleration? a)positive b)negative and for non-uniform acceleration? How would these look like

How do you formulate the Position Vector: x^m = [t____x____y____z] x^m = [f(t)____ax/2*t^2 + vx*t + x0____ay/2*t^2 + vy*t + y0____az/2*t^2 + vz*t + z0] dx^m / dt = [df(t) / dt____ax*t + vx____ay*t + vy____az*t + vz] What do you put in the"t" position "f(t)".

Homework Statement The position of a 60-gram golf ball sitting on a tee is determined within +- 1μm. What is its minimum possi- ble energy? Moving at the speed corresponding to this kinetic energy, how far would the ball move in a year?Homework Equations ## K\geq\dfrac {\hbar ^{2}} {2ma^{2}}...

I had posted this question here : http://physics.stackexchange.com/q/69003/540 I guess its appropriate to post links in here as question. This question is really puzzling me and any suugestion/comments are much appreciated and welcome.

If an object is subject to different forces at different times and these forces are totally unpredictable (the force at any instant after the current time cannot be predicted). How would we make the position change due to acceleration as accurate as possible? I have chosen a method but I've...

Hello, The quantum zeno effect is well understood and experimentally confirmed as regards polarization measurements (as discussed here). It's the quantum analogue of "the watched pot never boils" as it allows "continuous" measurement to inhibit certain state evolutions. Does the effect...

Suppose I have a particle confined between 0 and d on the x axis, and it has some wavefunction, if I measured the particle to be between some small interval [a, b], would the wavefunction collapse into a rectangle-like function with equal prob. density on the interval and zero outside? or what...

How is see by our senses a superposition of sensorially distinghible states in superposition, for example, superpositions of states with the same object with a separation of ≈1 cm??

I am working through chapter 10 of Griffith’s electrodynamics (for fun and in my spare time). While I don’t have a formal bucket list, getting to an understanding of how Newton’s third law is not as straightforward for electrodynamics has been on my mental bucket list. I am an engineer not a...

Homework Statement Initial velocity = 17 m/s Radius of curvature = 13 m Acceleration as a function of position = -0.25s m/s^2 Time elapsed = 2 s Solve for the magnitude of the acceleration. Homework Equations a = v (dv/ds) a^2 = a(t)^2 + a(n)^2, wherein a(t) is tangential...

Hello i wonder if anyone here can explain to me, why the wavefunction as a function of position is defined like this: $$\Psi(x,t) = \langle{x}|{\Psi(t)}\rangle$$ Why is it wise to use an inner product as a definition?

To my delight I was just called in for an interview for a summer position at a big research institute in the UK, as a graduating physics senior (advertised for undergrads). It's been a while since I last had a job interview and I've never had one at the professional/academic level, I would like...

I am working on a project where we will use a 3-axis accelerometer on the door and using the ax, ay, az data to calculate position and angle of the door. The accelerometer will be positioned near doorhandle. So the initial position of coordinate system will be there, where the accelerometer is...

Homework Statement A partcile starts att he point (1,0) and t=0 and moves along the x-axis so that at time t≥0 its velocity v(t) is given by v(t)= \frac{1+ t}{(1+t^2)} A) Determine the maximum velocity of the particle. B) Find an expression for the position s(t) of the particle at time t...