Measuring Definition and 962 Threads

Hi guys. How do astrophysicists measure the redshift of electromagnetic waves from galaxies due to gravity without the use of General Relativity? If I can be more specific, how do astrophysicists know that the gravitational redshift of light emitted from some part of a galaxy or galaxy cluster...

I would like to be able to measure the distance a sound wave travels. This is for a violin bridge and what I would like to do is apply a frequency corresponding to the frequency the string (196 hz for the g string) and determine the distance the wave traveled to get to the foot of the bridge...

Homework Statement In a probe that uses the Hall effect to measure magnetic fields, a 11-A current passes through a 1.33-cm-wide and 1.31-mm-thick strip of sodium metal. If the Hall emf is 2.42 μV, what is the magnitude of the magnetic field (take it perpendicular to the flat face of the...

From a purely theoretical standpoint, I'm quite comfortable with the concept of particle creation/annihilation, but, as a chemist, I cannot but feel that there's something missing in the way of interpretation, so I came up with the following 'explanation' of the phenomenon based on the measured...

Homework Statement A coil of fine copper wire has a resistance of 6.2 -Ω and a total mass is 14.4 g. What is the diameter d of the wire and what is its length L? (The density of copper is 8.96 g/cm3.) Hint Given: •Model the wire as a long cylinder of diameter d and length L. Write one...

I know that you can measure redshift from stars by looking at the shift in there balmer lines or more generally there line absorption spectra and seeing how far these lines have shifted from actual balmer lines or line absorption spectra of the same elements on earth. But how would you...

Homework Statement Set |Ψ> = (1/√ 2) | ↑, z> + (eiθ / √ 2) | ↓, z>. Find the probability of measuring the spin component of sz to be up the z-axis. Find the probability of measuring the spin component of sx to be up the x axis. Homework Equations I'm not sure. The Attempt at a Solution I...

Hello, I'm wondering, is it possible to define an operator that gives information about the "distinctness" of superposition components? As a simple example, imagine that we have two particles. Let |3> designate the state in which they are 3 meters apart, let |5> designate the state in which...

"We can’t make a measurement without influencing what we measure. before we look, there are only probabilities. When we open the box, they give way to a single actuality" It would be more like this, all the time, Until we look...

Hi, I'm trying to measure the electric field of the Earth using a simple set up and would just like some opinions on the viability and practicality of this method. The set up is as follows, two parallel metal plates with one larger than the other, the larger one is placed over the smaller at a...

Homework Statement Homework EquationsThe Attempt at a Solution 1. $$ [\hat {x}, \hat {p}_{y}] = \hat {x}\hat {p}_{y} - \hat {p}_{y} \hat {x}$$ $$= \hat {x}(-i \hbar \frac {\partial f}{\partial y}) - (- i \hbar \frac {\partial (fx)}{\partial y}) $$ Since x is not a function of y, it can be...

Is there any portable/small device that will allow me to measure the strength of the electron field emanating from the Earth's surface, i.e., the ground at a given location? Thanks!

I'm planning on carrying out an investigation with a golf ball and projectiles. Is there any type of equipment/sensor that I can used to measure the rotational speed/angular velocity? I know a gun chronograph can be used to detect the velocity but what can I used to detect the angular velocity...

I was reading up on the Andromeda Galaxy and it was saying that it was 2.2 to 3 million light years away from earth. So my question is how do we measure how far it is in light years?

wiki says "Experiments that attempted to directly probe the one-way speed of light independent of synchronization have been proposed, but none has succeeded in doing so" Here's a proposed experiment which I could not find any evidence of this being performed before.. Central light source...

Hi every one i hope someone can give me an idea how to achieve that. I am working for at school project, where i am trying to build a device that measure density of a multilayer object/enviroment. I am thinking to achieve that by measuring the axial force exerced while pushig the device inside...

I am not clear on the below, so any additional information would also be good. Let's say a pair of photons is entangled on 2 properties. When we measure on property A -- the values for property A (for both the entangled photons) becomes determinate/locked/fixed when we measure on property B...

Had a thought the other day. If a spool of a measuring tape was on a vehicle traveling close to the speed of light away from the Earth, with the spool anchored to the Earth, due to time dilation, would an observer on the vehicle see the spool unraveling faster than the speed of light?

I need to measure the resistance of a button on a car steering wheel, so my question is: how do I measure the resistance of a steering wheel button using a digital multimeter? I don't currently have the steering wheel installed yet, so can I measure the resistance of the buttons without the...

Hi, I have a question. I have measured with lux meter the illuminance of the room. When in front of the photoelement I put my plastics - colourless, green, red, blue. The lux value had decreased in the same tendency - from the colourless to the smallest value of blue sample. So, can I made...

Hi All, Recently I mentioned about a new method to measure the one-way speed of light. Quickly I was pointed to the existing roadblocks to such experiments, from members here and veteran professors in email. I have analyzed those roadblocks and putting here my understanding of the problems. To...

I need help in building a LCD flicker meter using photodiode and a current amplifier. The aim is measure the LCD pixels's flicker that can be detected by human eye so as to have a representation as electrical signal. This is to use it in cases where it's hard to judge if there is a flicker...

Suppose we have a closed system in which molecules cannot escape. Into this system we enter some radioactive molecules with \beta^+ decay. We know that the resulting daughter nuclide is also radioactive. We have some equations to describe the amount of parent nuclides and daughter nuclides...

Im doing a prac for school that we have to create ourselves. My groups prac goes along the line of a train pulling two carriages. Our train is a LEGO NXT unit that runs at a constant velocity, no acceleration. We will have two force gauges between each carriage and the carriage and the train and...

I'm interested in determining the density of a dough. I want to be able to continuously measure the density of the dough as it rises. My thought was to use an ultrasonic wave and measure the time it takes to reflect through the dough I would assume that as the dough ferments and the amount of...

I undertand that measuring a qubit's spin along a particular axis yields one of the eigenstates of the corresponding pauli matrices. I'm a little confused about what this type of measurement looks like mathematically. i.e how do you show the actual act of observing the qubits spin using the...

So, I recorded the result of a LabQuest 2 Vernier Magnetic Field Sensor on different points of a plane, with a solenoid in middle with a 5 amp current running through. I want to compare my results with theory, but have no idea what equation I'm supposed to be using. I assumed it was B = μ0ηI/r3...

Homework Statement Homework Equations For R, current I=E/R and for X, I=E/X... both are separate cases. The Attempt at a Solution [/B] Why does the balancing change? The potential difference across each resistor is E Itself right? I tried by assuming an arbitary internal resistance r...

Hi, Quick Qustion : If an object is propelled through the air (e.g. a ball is thrown), once the ball has left the throwers hand it will immediatly start to have negative acceleration (at least in the x plane). If the negative acceleration is measured at the same point in time after the ball...

when astronomers receive bursts of high energy radio waves from distant parts of the universe, how are they able to tell how far they have traveled? does it have to do with the wavelength?

Hi All, I'm trying to design an experiment for measuring force along a cable. The cable is will be held in a persons hand and the other end will be fixed to a transducer to measure the force of tension. In order to account for the multiple force vectors, I thought of using a gimbal table or...

Homework Statement Im not sure how to measure the wavelength when given this picture. Homework Equations The picture looks like this, it has two slits. The Attempt at a Solution My book says that the wavelength is 1 cm. When I measure from the middle of a white line to the middle of the...

Good day everyone! n00bie here. I did do a search before I posted this... found a lot of info, most of which I couldn't apply to what I am doing (because I wouldn't know how). I have something that I am working on that creates an electric field to alter certain chemical compounds. The distance...

When we measure distances in space -- for example, when we say a star is 20 lightyears away -- are we measuring in a straight line ("as the crow flies"), or are we including the dips and curves in spacetime (that light travels along)? Thank you in advance?

<< Moderator Note -- Dorea is an instructor asking about their physics lab >>[/color] The first experiment in our fundamental physics lab is "Measuring & Measurement errors". Currently we have four devices: - rule (0.5 mm) - Vernier Caliper (0.02 mm) - Micrometer (0.01 mm) - Spherometer We're...

I came across this problem which says" A pendulum is hung by roof of a train having mass 1 kg . The train then accelerates and pendulum makes an angle with vertical. What is acceleration of train? " Is it equal to gsinθ?

I want to measure the forc e of an AR15 recoiling over time from a single shot. The gun cycles at about 900 rpm, so the recoil impulses should be over within 67 miliseconds. There are two different parts to the recoil impulse. Within less than a milisecond, there should be a large impulse that...

I was wondering, since the Earth is constantly moving around the sun, the sun is moving around the milky way, and the milky way is moving through space (and for all I know the milky way might also be rotating around our local group, cluster, super cluster, etc.), how do we know how fast...

Homework Statement This is an example problem in my calculus textbook. I don't get how they relate the position vector to the force vector. I have taken a calculus based physics course and I don't remember establishing such relationship between the position and the force vectors. Note: I have...

What is the explicit 3x3 matrix operator which measures the colour of a quark? Essentially what I want to know is what is the analogue of ##S^z## for the measuring of spin.

I need to find the impact force that can be absorbed by these spacers as shown in the image. The spacers are radially distributed over the shell, and they are supposed to dampen any external impact loads to reduce the effective stress inside the inner shell. Since the FEA model is not showing...

Hi guys I have problem, basically I want to measure the power output from a water wheel. so basically I measured the power output by connecting the pulley that attach on the shaft of the water wheel. then this pulley is connected to other pulley which sit on the shaft of the DC motor. this DC...

Hi, I'm trying to measure the steady state velocity field behind the wake of a bluff body in the wind tunnel. My uni is equipped with 4-hole cobra probes which is capable of receiving flow within a 45 degree cone of acceptance. As the base of a bluff body dominated with re-circulating flow...

I've been searching over this and I don't quite get it yet. I just heard about this "z" parameter for gravitational red shifting and I thought it'd be fun to apply into the scenario of a solar-mass black hole. The equation I looked at was (1/(2GM/c^2r)^0.5) - 1 = z So, like, does the z parameter...

I have been trying to find an ammeter that can perform a specific task and failing miserably. I would appreciate any help I can get. and as you may soon notice, I have no engineering background. I am trying to find a non-invasive method for measuring the current generated in an electrosurgical...

1. Homework Statement hi i need to perform the experiment described in this link http://www.phywe.com/index.php/fuseaction/download/lrn_file/versuchsanleitungen/P2430400/e/P2430400.pdf so i need to measure the torque in the experiment they use Torsion dynamometer to do the job but i need to...

Hello everyone. I'm working on a physics lab project and I've reached a barrier. I need to measure the torque on a closed loop in a magetic field and I can't reach a way to do so. Of course, excluding all the torque measuring devices and such which I believe we don't have at the lab. Any ideas...

Homework Statement There is an air-tight 1L Canister filled with 90% water and 10% N2O. This canister is attached to some clear tubing which is not entirely air-tight. At the end of this tubing are some tungsten particles averaging ~1µm in diameter with total mass of 60mg. The contraption is...

I'm trying to create a quantum circuit which does the following very simple thing: Alice has two qubits, and she wants to measure the observables: X⊗Z, Z⊗X, and Y⊗Y, each taking values in {-1,1}. Note that this is a commuting set of observables, so it should be possible to measure all three...

Ever since Einstein showed us that time is relative, and that there is no such thing as independent time but a space-time fabric, and since we’ve got experimental results about the dilatation effect that speed and gravity/acceleration have on time: Is it OK to say that the universe started 13,79...