Errors Definition and 347 Threads

Hello! I have a question that maybe has to do more with Mathematics, but if you do experimental physics you find it quite often. Let's assume that we want to measure two quantities x and y that we know that they relate to each other linearly. So we have a set of data points xi and yi...

Homework Statement For a lab, we explored Kirchhoff's Laws. I made a procedural mistake while measuring my voltage values across my different elements. I know that all of my calculated voltage sums are correct, so I was wondering what I might have done to have loops ACBA and CDBC have almost...

Hi PF! Attached is a screenshot of my code: The issue I'm facing is not being able to plot at line 21. It's weird because when I evaluate ##\alpha[1/4]## on it's own line I instantly receive a 5X1 vector. When I evaluate the Table[##\phi##] statement also shown in line 21 on it's own line I...

Please bear with me... In a curriculum in mechanical engineering, there is a set of standard topics: statics, dynamics, vibrations, fluid mechanics, thermondynamics, etc. What is Artificial Intelligence, and what does it entail? (at the moment, it seems like a buzz phrase that does not...

Homework Statement Given X_1,\dots,X_n a simple random sample with normal variables (\mu, \sigma^2). We assume \mu is known but \sigma^2 is unknown. The hypothesis is \begin{cases} H_0: & \mu=\mu_0 \\ H_1: & \mu=\mu_1 > \mu_0 \end{cases} Determine the rejection region R...

Homework Statement What errors did Rutherford encounter in his experiment and how did he account for them. Homework Equations I believe there is an equation to find (b) but I don't know what it is.

Hello, I'm carrying out electrical resistivity tests with the Van der Pauw method on a round sample (2 mm thick disk) of a doped ceramic but sometimes I have issues in the mounting of the sample. I'm using a 4-probe tube where each of the 4 wires contacts with the "corners" of the sample. To...

Homework Statement Hi, I have a question about uncertainties. If I am carrying out an investigation I need to record my uncertainties in each measurement. I am aware that instruments have reading errors. So, if I use a stopwatch to measure the time period of a pendulum the reading error is...

Hi, as a side project I am making a solar system simulator in Python, but I am getting extreme inaccuracies. As the image shows - I am comparing the simulation to data obtained from NASA's Horizon. I have written a a basic Verlet integrator in the Python class posten below: import numpy as...

I am using fortran 90 to solve a elliptic partial differential equation numerically(Poisson's equation) and I have encountered a underflow error. All the arrays involved are stored as real data types. The original expression is highlighted in the comments and the my attempt at refactoring into...

Homework Statement Figure 2.2 (attached) shows a graph of distance against time squared for a ball bearing falling through the air. In accordance with s = ut + 1/2 a t^2 the graph should be a straight line through the origin. Explain how a systematic error in s and t could lead to the graph not...

So I just began a course on Linear Algebra, and was curious about how we can estimate derivatives using centered differences: After a few minutes of Research, I find the proof involving something about a truncation error, which led me to the conclusion that when estimating derivatives, the rate...

I need to resample a set of data and its errors linearly in log space, with the same number of points. I was just going to interpolate between points to get the data - but how do I calculate the errors?

Homework Statement I am having troubles trying to figure out systematic and random errors when conducting Young's double slit experiment. Homework Equations NA The Attempt at a Solution I have found one error which could be correct, it is the fact that the laser was not at right angles with...

Homework Statement Suppose that there is some hypothetical cosmological parameter called C, and suppose that the real value of C is C(real) = 1. Also suppose that everyone in the universe is able to measure C. Our value of C is C(ours) = 1.15 +/- .15 at confidence level 95 % Make an...

So let's say I do some measurements and obtain a set of measured values. The measurement is characterized by random errors so by making enough measurements, they approach a normal distribution. In other words, my set of measured values can be approximated by a normal distribution characterized...

Hello, I have a set of data, two columns, and each datum has its measurement error like illustration shows below: x | y --------------|----------------- x1+/-xe1 | y1+/-ye1 . | . . | ...

Hi.. I want to know how can we specify the data(electrical) passing through cable that we are designing in CST design studio to test the effect of EMI on the data passing?

Homework Statement What is the uncertainty in 5.00mm measured by an analog device? Homework Equations No equations, Uncertainty and error analysis question The Attempt at a Solution I know that the uncertainty is half the smallest division but i can't figure out what is the uncertainty and...

I was reading an 1803 paper by Thomas Young (of double slit fame), "Experiments and Calculations relative to physical Optics". In it, he lists various dimensions of fringes of light and things. All without any error bars. It got me thinking, what's the history of error bars in scientific...

Homework Statement So we had to the simple pendulum experiment and were measuring the effect of the length of the pendulum on its period of motion. However, our results produced a line of best fit that was significantly higher than the expected line of best fit (with length vs period squared)...

Hi, Jake here. I've created some graphics about solar cells that covers high level, general info and even delves into some atomic-level subjects. However, I'm no physicist and I'm sure it shows. If any of you could take a quick look at my work and review for errors, that would be awesome. My...

Hello I have a set of data points, with errors (X1 , Y1 +- deltaY1) , (X2 , Y2 +-deltaY2) etc I have the covariance matrix for these bins I want to integrate this set of data points: SUM_i ( Y_i * X_binWidth_i ) How do I combine the errors, taking into consideretation the...

Homework Statement [/B] The surface tension (T) is measured by capillary rise formula T = \frac {rh ρg}{2 cos\Theta} . The quantities of ρ, g and θ are taken from the table of constants while the height and diameter are measured as h = (3.00 + 0.01)cm and D = (0.250 ± 0.001)cm Find the...

Homework Statement I am just looking through some old notes I have from for cosmology, and there's something cropped up that i can't seem to figure out: Say I have two (or more) values for H_o each with errors such as: H_{o_1}=70^{+a+b}_{-c-d} and H_{o_2}=69^{+e+f}_{-g-h} How would I go...

I am having difficulties understanding this program may someone help me please. Using the CelsiusToKelvin function as a guide, create a new function, changing the name to KelvinToCelsius, and modifying the function accordingly. #include <iostream> using namespace std; double...

Mod note: Thread title changed from "Sign used in total differential and small errors" to "Symbol used in total differential and small errors" My notes say that z=f(x,y) can be defined as the sum of the changes with respect to x,y respectively. The formula is: dz = ∂f/∂x * dz + ∂f/∂y * dy...

Homework Statement A student is testing the kinematic equations for uniformly accelerated motion by measuring the time it takes for light-weight plastic balls to fall to the floor from a height of 3 m in the lab. The student predicts the time to fall using g as 9.80 m/s^2, but finds the...

Homework Statement I have doubt in calculating the permissible error. It goes as follows Measure of two quantities along with the precision of respective measuring instrument is A = 25.0 ± 0.5 m/s, B = 0.10 ± 0.01 s. A physical quantity C is calculated as C = A × B. What will be the value of...

do anyone explain me pl. i would like to know the uncertainty error in measuring the specific activity of the primordial radionuclides

Homework Statement I did a lab this week measuring periods of swings of a simple pendulum. We need to curve fit the equation T=k*l^n and we got ln(T)=n*ln(l)+ln(k), and we need to plot the data we collected into the linear graph, meaning out y axes is ln(T) and our x axes is ln(l). So far all...

haruspex submitted a new PF Insights post Frequently Made Errors in Vectors - Elementary Use Continue reading the Original PF Insights Post.

Homework Statement First of all, I used the Window xp & Compaq Visual Fortran 6.6 installed in VMware workstation. In my case, there are no compile and link errors in source code, and excuting that program is also done. But I want to generate 300 random numbers by using my program (Log-normally...

So I did a lab where we are calculating the acceleration due to gravity using a variety of methods. For two of the methods, we have an object attached to a magnet, then the magnet is turned off so the object is in free fall and it makes a spark/mark every 1/60th of a second on a piece of tape...

HI everyone, Imagine we are sampling of a gaussian signal along time and need to know the power/variance associated with the first N spectral components. So we take our favorite fft algorithm to get the PSD. The error associated with a given estimated spectral component f(w) (w is the...

Hi! I am currently trying to write a code in C to simulate the orbit of planets around the Sun in the solar system. I am using the velocity Verlet approach and finding that my code produces no acceleration in the ##y##-direction (aside from for ##t_n = 0##,) and that the planet just flies off...

I am reading Mark Newman's Computational Physics textbook. He goes over calculating integrals with Simpsons's Rule and the Trapezoidal Rule, and then he goes over calculating their errors. Why would I have to ever worry about the error of the integral? He has the chapters online at his website...

haruspex submitted a new PF Insights post Frequently Made Errors in Climate Science - The Greenhouse Effect Continue reading the Original PF Insights Post.

Homework Statement Hello! In our class, we just completed a lab on momentum and energy conservation in collisions. It was a computer simulation. Although, for the lab report, the teacher wants us to write the random, systematic, and human errors. Can someone describe what each error means? What...

Let's say you know all 3 cartesian components of a particle's velocity and all 3 for it's acceleration. You can split the acceleration vector into two vectors, one parallel (longitudinal) to the velocity vector and one perpendicular (transverse) to the velocity vector. Then, I found the...

Dear All, i am new to Maxwell 3D software. i want to simulate my Wireless Power transmission Project in Maxwell, for this purpose i took help from different toturials whic abled me to draw the Tx and RX coils...i want to simulate these coils to calculate the values of L, M, K and etc. but i am...

I was looking at the attached picture, where it gives the Higgs Mass obtained from the two different channels from ATLAS and CMS. Let's only talk about the diphoton channel : H\rightarrow \gamma \gamma From the ATLAS the mass value is: m_{Ah} =126.02 \pm 0.51 and the CMS: m_{Ch} =124.70 \pm...

Hi guys, so I'm having a little trouble completing my physics lab report here due to not being able to find many errors to discuss about. The experiment that I conducted makes use of a basic current balance: http://www.pasco.com/prodCatalog/SF/SF-8607_basic-current-balance/ As you all know...

Homework Statement You make a measurement of two variables with 100% correlated systematic uncertainty: x_1 \pm \Delta x_1^{stat} \pm \Delta x_1^{sys} = 1.0 \pm 0.1 \pm 0.1 x_2 \pm \Delta x_2^{stat} \pm \Delta x_2^{sys} = 1.2 \pm 0.1 \pm 0.2 The average is taken by: \bar{x} =...

I've got GPS nearshore bathymetry/beach topography sand elevation data from the backbeach out to 8 meters depth, with 1 m spacing in the cross-shore, 100m spacing in the alongshore, and stretching multiple kilometers of coast. I have interpolated the data using a couple different interpolation...

haruspex submitted a new PF Insights post Frequently Made Errors in Heat - Elementary Level Continue reading the Original PF Insights Post.

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Hello What are the possible errors when measuring pressure value by the using a transducer? And how we can find the amount of errors?

haruspex submitted a new PF Insights post Frequently Made Errors - Pseudo and Resultant Forces Continue reading the Original PF Insights Post.

haruspex submitted a new PF Insights post Frequently Made Errors in Mechanics - Springs Continue reading the Original PF Insights Post.

My code: import numpy as np import matplotlib.pylab as plt import math import random from scipy import integrate R1 = .001 R2 = 7 def G(r,theta): sigma = random.randint(4000., 7000.)/1000. # width of beam is 4 - 7mm r0 = random.randint(0, R1*1000.)/1000. #random centroid theta0 =...