Measurement Definition and 1000 Threads

Recently, I've been pondering deeply on relativity (both Galilean and SR) and all of a sudden I find that I don't grasp even the basic concepts of physics (or life) anymore, i.e. I can't go back to my previous, "normal" mode of thinking. Consider Newtonian mechanics, take the ground to be at...

I was wondering, how can we measure the rotational velocity of a galaxy? In practice knowing the mass distributions and so on, we could calculate it by classical mechanics (or maybe GR). However people measured the rotational velocity of the galaxies and found that it doesn't correspond to the...

Would a Klein Tools Non-Contact Voltage Tester or similar be able to measure static electricity? If not what will? https://www.google.com/search?q=how...hop&q=Klein Tools Non-Contact Voltage Tester

I measure the Electromagnetic Field Radiation at a point for example x distance from a source, and i am reading for ex. 15 milli volts per meter. Are these 15 millivolts per meter, equals to 15 milli volts ? I mean, if i do the opposite procedure, and receive a reading of 15 milli volts, at a...

In Every measurement there must be uncertanity.In length or In time everything.Lets assume we have a ruler and a rope.If I measure the rope I get a result but I can't say this is exactly true because there's a unncertanity in measurement.Lets suppoe the rope is 100 cm minus or plus 0.5 mm.The...

Hello, I'm trying to design a strain gauge load cell for force measurments. I have few questions regarding that. Q1: how to calculate the minimum froce that my load cell can detect? Q2: how to calculate the FSO(full scale output) of my load cell? Q3: Is there any way to measure the...

The objective of this post is to: (i) generate a discussion of whether results of the double-slit experiment address solely the nature of matter, or do the results also address the nature of probability; and (ii) to determine if there have been any comparably structured experiments outside of...

I have made measurements using Vernier Calipers. What I don't understand about them is the coinciding thing. How does one know the value of the last digit of the measurement by seeing which marker of the main scale coincides with the Vernier scale?

The question is as in the title. I feel that it doesn't change the mausrement.

1. The problem statement, all variables and given/known data I am trying to experimentally measure the torque of a stepper motor at various velocities. I'm not quite sure how this should be done. Here is a diagram of my proposed method so far: Basically a weight is to be suspended from the...

Hi, I have an experiment set up to get two beam interference fringes. I would like to know how I could measure the actual amplitude of the irradiance from the experiment. I have with me a power meter and a CMOS camera. How can I go about this? Thank you

I'm reading stuff about weak measurements with post selection and its likely ability to improve computational performance. What I'm curious about is whether weak measurement is a real thing or not. There are many papers showing how to do the measurements and the theory behind them, and then...

How can we see if a quantum measurement is sharp or unsharp ? can we measure unsharpness? Thanks

I wanted to ask something concerning the errors... Why sometimes the errors are taken to be \sqrt{N} where N is your measured value (such as the number of counts from a detector) and why is it sometimes given as half of your device precision (eg a common ruler's error is 0.5mm)? In my case I...

A body of unknown mass hangs from a spring and stretches it to 50 cm. If the spring constant is 104 N/cm determine: a. the weight of the body b. the mass of the body k = mg/∆L W= Mg mass : k = mg/∆L 50/104= .4807692308 weight : W= Mg .4807692308*9.8=4.711538462

Hey, I have a question about Measurement Theory. I am reading Quantum Mechanics by Ballentine chapter 9 Measurement and Interpretation of States. Please check the following pdf for my question: thank you VVS

Dear All, I am not sure if this is the right place or not for this post so i apologise in advance if not. I am trying to find some pressure sensors / transducers to measure the pressure difference (with respect to static pressure) at points on a circular cylinder model installed inside a...

Hi, I'm trying to use a small PM DC motor as a generator to convert mechanical energy to electrical energy. I couple that small generator to another DC motor with spur gears and I measure the current of that small generator while it is driven by the DC motor at fixed speed. The circuit of...

Hello all, as a recent graduate and a new teacher, I am living in Honduras and teaching the sciences in a high school setting. I did not study to be a teaching by got my bachelors in Spanish and Physics. I am working at a bilingual school and my resources are extremely limited. My question is...

I am doing research on synthesis of copper nano particles. I would like to have a cyclic voltammetry (CV) of this material but I don't know how to prepare sample. Please tell me the ways to carry out this measurement. Thank you so much!

Homework Statement This is a statistics as applied to astronomy problem. My stats knowledge is horrible. Anyway, the problem: For several hundred objects, I have a number of different properties for which I have a measurement & associated measurement error. For example, flux density and...

The proton current in cyclotron are normally measured by Faraday Cup. However, I do not understand that if there is target material for the proton beam. Proton is fully stopped in the target material, for example, water. How the current is measured if it did not hit anything else?

I have never been to the pyramids in Egypt. I'd love to go one day. I am sure their configuration will be just as others have seen, and as the visitor map describes. Why is it that my experience will correspond exactly with others' experience if I am collapsing quantum potential with respect to...

Let's say a student does a simple experiment where she conducts 10 trials at each x value (at each value of the independent variable). She collects data over 30 x values, giving her 300 total trials. For each of the 30 x values, she averages the 10 y values and she calculates the standard...

Hi, let's say I want to measure the frequency f of a periodic signal. I may take N data points with an arbitrary timestep of T. The question is how shall I choose T for a fixed N to have the best accuracy? In principle the frequency resolution is 1/(N*T) when taking the Fourier transform...

Hello Forum, An event is a point in spacetime with spatial coordinates and a time coordinate: (x,y,z,t). An event does not have a duration since it only lasts for an instant t. We can talk about time duration to mean the temporal separation between two different events, correct? In the...

Quote from this recently posted article. http://www.nature.com/news/physics-bell-s-theorem-still-reverberates-1.15435 “Quantum theory does not predict the outcomes of a single experiment, but rather the statistics of possible outcomes.” My question is not in regards to the statistics of...

I was just thinking about this, and from a perspective of an inertial frame, it's easy to see how distances contract, times dilate, simultaneity varies between observer and the speed of light is exactly c in each case. But what about non-inertial frames? In the presence of gravity almost...

Homework Statement Hey guys! I'm new here, so firstly- hello! I've a exercise to from Metrology. Evaluate measurement uncertainty for the following measurement: 1. Measurement quantity: length of a bar L = 500 mm 2. Material of the measuring object: steel 3. Temperature range in the...

This question is inspired by reading Arnold Neumaier's article on Everett's measurement theory: http://arnold-neumaier.at/physfaq/topics/everett Suppose I have a system whose state lies in a two-dimensional Hilbert space, and I want to model a measurement of its state as a unitary evolution...

I have been reading and would be interested in feedback to the comments that I make, below. One of the points made in this paper is that the interpretation of the uncertainty relation needs to be re-examined in its relation to the viability of having simultaneous measurements of A & B. For...

I am working on an experiment where I need to measure the Delta T across a heat ex-changer. I have two independent T Type thermo couple, one at the inlet and the other at the outlet. Both tied to an Agilent data logger. I normally put the data into an excel sheet and generate Delta T = T1 - T2...

Although the subject line might seem to put this question inside general relativity, the reason I put it in quantum physics is because I would like to know what happens when one treats a singularity as a particle. Obviously from outside the event horizon, one cannot do this, but inside the event...

Hello guys, Homework Statement the problem goes as follows: "Which measurement should you do on a statistical ensemble of qubits in order to distinguish between the pure state |Ψ>= cos(θ)|0> + sin(θ)|1> and the mixed state ρ=cos^2(θ)|0><0| + sin^2(θ)|1><1| " Homework Equations I am not...

Hi everyone, I'm currently a mechanical engineer interning at an HVAC company. I need to measure the resistance of a fluid through ductwork. The CFD shows a linear curve through a plenum when plotting R vs volumetric flow rate. For example, a straight rectangular box 1 1/16” by 2.5” and 3ft...

Pardon me for my ignorance. This is a question of curiosity. I look for a concise logical argument as to why the community believes the following hypothetical situation and explanation is wrong. What justification is there for believing in waveform collapse at time of measurement? Is it...

Hello everybody ,A friend of mine told me that best way (The most accurate) to do this is grating diffraction experiment , What u think? Thanks in advance

Hi: I have been working in this Project for a while now and I would like to share the results with you. Still needs some improvements; but it appears to be working fine so far. Please let me know your suggestions and ideas. Thanks.

Homework Statement Homework Equations The Attempt at a Solution I have managed to do the first 3 parts of the questions. The last two 4 markers are the ones I am having difficulties with. I have tried using the expansion postulate which states the wavefunction is equal to the...

Hi all! Basically I will soon be required to measure the torque required to drive a plunger pump which operates by an eccentric cam on the pump's driveshaft pushing a plunger up and down. So obviously the torque will vary through the driveshaft's revolution. The setup is as follows: Motor...

Homework Statement I did an experiment to measure air flow using a pitot static tube and a venturi meter. First attempt: I connected both long and short manometers to the pitot static tube. Then I switch on the fan. The difference in manometer reading is 0.59kPa, which is the pressure. Then I...

I am asked to indicate the uncertainty on the radius R of rotation of the plumb bob. Please see picture. Basically, there is a vertical shaft, over which is attached a horizontal shaft and a plumb bob is hung over with a thread on the horizontal shaft. The bob is attached with a spring to the...

I was just wondering if there's a way to measure pain. I figured it'd be and equation like current. Like voltage would be the amount of pain, ohm would be a persons resistance to pain, and current would be the pain they actually felt.

Hi, I am looking for an introduction to heat capacity measurements at low temperature (10K). (For example for producing the linear dependence of the electronic heat capacity on T). I fail to find a simple introduction. Can anyone mention keypoints or a good source? Thank you!

Is there a way in electrical engineering where I can convert 230 KV to 5 V such that the 5 V wave has same amplitude, phase and frequency as that of 230 KV.

Hi, My question is partially motivated by this discussion. Suppose we have a pure state that is in a superposition for a certain basis, e.g. ##\left|\psi\right\rangle=\alpha\left| 0\right\rangle+\beta\left| 1\right\rangle##. Now a colleague of ours measures the state with respect to that...

1.What do watts do and how do they affect an electrical device like a motor? 2. what do amps do and how do they affect an electrical device like a motor? 3. what do volts do and how do they affect an electrical device like a motor? I understand what these measurment are and how to solve for...

Hi! I'm breaking my head about the following problem: Consider an A/C at a certain velocity flying at a certain altitude. The A/C measures it's speed via the difference in total- and static-pressure and applying bernoulli. Now the aircraft accelerates. What happens? At this point I get...

Hello all, I have to measure the compression strength of a porous ceramic body (d=L=10 mm) using advanced force gauge, mecmesin and don't have any experience with it. The simple procedure, which I followed, was to measure the force at which the sample started to break, divided by the cross...

Decoherence relationship to the "measurement problem" I have heard the argument that "decoherence" in quantum states causes the quantum collapse to occur, and that this solves the "measurement problem". But I'm still left with a nagging question... Does decoherence only produce quantum collapse...