Accuracy Definition and 236 Threads

  1. W

    Examining the Accuracy of a Movie Scene

    This is from a stupid movie, lots of new age nonsense etc. However, please disregard that and judge this segment on its own merits. Is it accurate? I am not being sarcastic or have a hidden agenda. I just want to know!
  2. S

    Accuracy of Kirchhoff diffraction theory

    Hi guys, My research project involves a paraboloidal telescope with a primary diameter of 25 meters, and a focal length of 10 meters. My goal is to come up with the mathematics and numerics to determine the surface profile error of the primary mirror. We will take a point source of 2mm...
  3. P

    Measuring Pi/6 for Peak Height Accuracy: +_20 or +_10 m

    Homework Statement A hiker is at the base of a mountain and can get the horizantal distance between himself and the peak through GPS device:750 m. And suppose we know the actual measurements: It's a right triangle with an opposite= 750 tan (pi/6) = 433 m , an adjacent= 750 m, and a...
  4. G

    Mathematica [Mathematica] Accuracy of a function

    Hello all :smile: I have a very complicated function, let's call if f. My problem : f[0.01] does not give the same result as f[1*^-2] because of accuracies. In the first case, the argument 0.01 has machine precision which is not sufficient in my case and the result is wrong. In the second...
  5. C

    Testing Eigen Values: How to Check Accuracy Before Finding Eigen Vectors

    Homework Statement This is probably a really simple question , but how do i test my eigen values to see if there right ,---------- (A-tI)x=0 where t is an eigen value , I know how to test if my eigen vectors are correct but how do i test to see if my eigen values are right ...
  6. russ_watters

    What is the Accuracy of Airflow Measurements Using Multiple Devices?

    I ran into an issue on a project where I'm needing to be sure of the accuracy of airflow measurements being taken. There are two basic ways to measure the airflow of an air conditioning system: 1. First is to traverse the main supply duct with a pito-static tube array and a differential...
  7. M

    Affect on volume of solute/solvent on accuracy of Rate Law

    This was part of a lab i preformed to determine rate law for HCl and Mg. 50 mL of 0.5M, 1M, 1.5M and 2M HCl solutions were made using water and this was used with Mg ribbon to find the rate law. The same 0.5M, 1M, 1.5M, 2M HCl solutions were made in 100mL solution that contained water. I was...
  8. M

    Does Stirring Increase Accuracy of Rate Law Calculation?

    An experiment was done by me to determine the rate law of a reactant. If the reaction occurred faster(ex. by just stirring reactants), would the accuracy of rate law calculated increase? If it doesn't increase accuracy, then what is the point of stirring/swirling the reactants? I think that...
  9. M

    Accuracy of the exploding asteroids in The Empire Strikes Back movie

    http://img718.imageshack.us/img718/2489/asteroidtiming.jpg Here is a scene of a star destroyer firing on an asteroid. The entire explosion takes about 10 frames of video -- less than a third of a second. It's widely believed that the asteroid in question is about 40 meters in diameter and...
  10. N

    Accuracy of Fundamental thereom compared to MVT

    Hello! The Mean Value thereom gives F(b)-F(a) = f(c).(b-a) Where f is F' and c is the value of x at which it's derivate is equal to the average rate of change over the interval a to b for F. The Fundamental thereom of calculus also gives F(b)-F(a) = (\frac{1}{b-a} \left \left \int...
  11. C

    Improving the accuracy of a Java simulation of n-orbital bodies

    Homework Statement So, I'm creating a 2d graphical simulation of orbiting bodies. Right now I'm just working with 2 bodies, one stationary, but I would hope to extend this program to be able to include any number of moving bodies and have them interact accordingly. After combing...
  12. F

    Approximating mac/taylor series to z decimal accuracy

    Homework Statement Any problem. Ex Use the Mac series of tan^{-1}\left(x\right) to approximate at x=\frac{1}{2} to three decimal place accuracy. Homework Equations \sum^{\infty}_{k=0}(-1)^{k}\frac{x^{2k+1}}{2k+1}=x-\frac{x^3}{3}+\frac{x^5}{5}-...The Attempt at a Solution I found out using...
  13. A

    Clock Skew on PCs: Investigating Today's Accuracy

    Anyone know what a typical clock skew would be on your average PC these days? Updating my clock with NTP it appears my laptop (when running 24h and not in idle mode) drifts about 2 seconds a day. I get the impression that's a lot. (John Harrison was building better mechanical clocks 250 years...
  14. B

    Accuracy of generation time estimate

    Homework Statement How accurate is the estimate for (cohort) generation time (the type you'd have on a life table)? Homework Equations Cohort generation time: Tc = Sum of (x*Fx)/sum of Fx The Attempt at a Solution Tc = 2.77 (for 7 generations) So the generation starts of with...
  15. W

    Degradation in Source Location Accuracy in the Presence of Sensor Location Error

    Hi guys, i was given a project based on the above topic and i know very little on it. Can anyone help to explain what's the difference between MSE and therotical MSE. Taylor series estimation and the modified taylor series. Thanks
  16. N

    Amount of Terms Required to Find a Sum at an Indicated Accuracy

    Homework Statement Show that the series is convergent. How many terms of the series do we need to add in order to find the sum to the indicated accuracy? \sum^{\infty}_{n=1}\frac{(-1)^{n}}{n*9^{n}} (|error| < 0.0001) Homework Equations Alternating Series Test General knowledge of adding...
  17. I

    Load Cell Accuracy | Capacity >200Kg | 10g or Better Accuracy

    Hi Everyone, I've been trying to find a load cell for a report and I need one with a maximum capacity of >200Kg and and accuracy of 10 grams or better (used in compression). I've taken a look on the web and the highest accuracy I can find is about 0.03% of the maximum capacity; which with a...
  18. U

    Calculating the Relative Error & Improving Accuracy of Measurements

    Hi Can anyone help me to solve the following question; Note: in both equations the +/- is written above and below of each other without the '/' sign. Thanks.
  19. Pengwuino

    How Accurate Is a Typical Wooden Meter Stick and Protractor?

    I was grading my labs and in this lab, we used a meter stick and a wooden protractor. A group finally wrote in their write up that they believed the error was due to the inaccurate nature of the equipment. This begs the question, what sort of tolerances do you see in the manufacture a typical...
  20. G

    Mathematical impact of outliers on accuracy of models

    Is there a general approach to calculating the impact outliers have on the accuracy of one's (predictive) model?
  21. D

    Required Precision for GPS Distance Measurement

    Homework Statement GPS can be used to determine positions with great accuracy. The system works by determining the distance between the observer and each of the several satellites orbiting Earth. If one of the satellites is at a distance of 20,000 km from you, what percent accuracy in the...
  22. Q

    Measuring energy of photon to within some accuracy

    Homework Statement Estimate the minimum length of time needed to measure the energy of a photon to an accuracy of 10^(-15) Joules. Homework Equations E = hv, where v is the frequency of the photon and h is Planck's constant in J*s Watts = Joules/second The Attempt at a Solution...
  23. S

    Which Type of Sensor is More Accurate: Thermocouple or RTD?

    I wonder whether the accuracy of that thermometer with a type K sensor is as follow: encironment: 90'C Sensor type: resistance sensor so the accuracy = +/- 90*0.005+0.5 = +/-0.95'C Thanks for your help.
  24. T

    Absolute Zero and Absolute Accuracy

    This is either a topic that is so blatantly obvious that it's ridiculous I'm saying it, or I'm missing something. From my limited physics knowledge, I know that absolute zero is a temperature in which the molecules are not moving whatsoever. In other words, it's the lowest possible...
  25. R

    Use taylor's THeorem to determine the accuracy

    Use taylor's THeorem to determine the accuracy of the approximation: cos(.3) ~=1 - (.3)^2 / 2! + (.3)^4 / 4! when i use taylors theorem, i use (.3)^4 / 4! which gets me 2.03e-10 but the asnwer is R<=2.03e-5
  26. Averagesupernova

    Acceptable accuracy spec of an hourmeter.

    So, as the title says... - What is an acceptable spec? We're not talking in seconds per year or anything like that. Does anyone know a rough industry standard? - This hourmeter will be designed into a machine that will accumulate a couple thousand hours a year max. A .2% accuracy will...
  27. K

    Understanding Precision and Accuracy: Demystifying Uncertainty in Measurements

    Please explain uncertainty and give examples like i know it is 'half the smallest degree' just not suree.
  28. B

    Greatest accuracy in the |mn> state is |n| = m

    How do we show that the greatest accuracy in the |mn> state is |n| = m for the Mx and My components?
  29. G

    Oscilloscope Accuracy: Investigating Data Reliability

    Hi I have done my experiment by using an Oscilloscope, (10 k ohm) resistor and 220 nF capacitor and a probe to find the the V out and then finding Gain and phase shift, my question is what's going to affect the accuracy of the data being received from the experiment results?
  30. T

    Verifying the Accuracy of a Gun Aimed at a Falling Target

    Homework Statement A gun is aimed directly at a can, which is simultaneously released when the gun is fired. This gun won't miss as long as the initial speed of the bullet is sufficient to reach the falling target before the target hits the floor. Verify this statement. Homework...
  31. L

    Finding Sum of Alternating Series to Desired Accuracy

    How many terms of the series do we need to add in order to find the sum to the indicated accuracy? The alternating series from n=1 to infinity of ((-1)^(n+1))/(n^2) |error| less than 0.0399 i got it down to 1/n^2 is less than 0.0399 but i can't figure out if n = 5 or n=6... please help:(
  32. L

    How Accurate Can Magnetic Moments Be Measured with a Torsion Oscillometer?

    Homework Statement The oscillation period of a torsion oscillation magnetometer of T=3s can be measured with an accuracy of 1µs. Let the moment of inertia of the sample and holder have a value of J=10-6kgm2. Evaluate the accuracy with which a small magnetic moment can be determined...
  33. F

    Can Atwood's Machine Measure Gravitational Acceleration with 5% Accuracy?

    Homework Statement We hope to use Atwood's machine to measure gravitational accleration with an accuracy of 5% [(Delta g)/g = 0.05]. Mass m1 is heavier than m2 and it falls through a distance L. We are able to measure time with accuracy of (Delta t) = 0.1s. If we say, for any x, (delta...
  34. cepheid

    Use of σ in quoting measurement accuracy

    I know that σ is the symbol typically used for standard deviation, but what does the use of σ mean in these contexts? ex. 1: "[our fancy new instrument] ... allows for the identification of > 500 sources at greater than 10-sigma" ex. 2: "These estimates assume ... a 1σ polarization...
  35. I

    What is the most accurate method for measuring 6 mL of water?

    Can anyone please tell me which one of the following is the most accurate method of Volume measurement for 6 mL of water (density= 1g/mL): Graduated Cylinder, Pipet, or Buret. Also, how can you explain your answer. Every help would be appreciated.
  36. G

    Accuracy, Fibonacci + Golden Ratio

    I have been curious about this for a while... I'm interested to know if there is any easy way to tell the accuracy of the (n+1)th on the nth term of the Fibonacci series in relation to the golden ratio. I know that as n tends to infinity the ratio tends to the Golden Ratio "Phi" - but is...
  37. N

    Accuracy of Numerical Integration Methods

    Hi, does anyone know what sort of methods I could use to test the accuracy of the numerical solution of the integral equation? Many thanks
  38. M

    Accuracy of Current and Voltage Measurements

    In general, are the measurements of current or voltage more accurate? From our lab experiments, it seems that voltage is more accurate. I'm curious as to why this is the case. My guess is that because current itself is the measurement of the flow of the electric charges it would be more...
  39. S

    Accuracy of Gravity: -9.8m/s/s +- _______m/s/s

    I am working on a lab and I need to know the accuacy of gravity=-9.8m/s/s? So I need the +- blank after the -9.8m/s/s. -9.8m/s/s +- _________m/s/s Thank you Stephen Doty
  40. G

    Improve Your Arithmetic Accuracy with These Helpful Tips

    I need help making my basic arithmetic more accurate. [eg. 2*2=4] If anyone has any suggestions they are greatly appreciated. The Attempt at a Solution I tried some online games but they don't help very much. Is it really just practice practice practice?
  41. C

    How Do You Solve Complex Error Propagation Problems?

    [SOLVED] Accuracy &amp; Error Hi Everyone, Just a quick question regarding Accuracy & Error. We have been doing this for a little while (University) and I'm slightly confused with one of the problems. I am able to do something like this and achieve the working and answer: (7.3 ± 0.4) x (1.2...
  42. W

    Accuracy of finding eigenvalues of defective matrix

    Homework Statement Hi all, I need help with determining the accuracy of finding eigenvalues of defective matrix. The question asks: When a matrix has a defective eigenvalue, the condition number for computing its eigenvalues is infinity. Does this mean that these eigenvalues cannot be...
  43. D

    Solving for k & P0: 5 Decimal Places of Accuracy

    From the facts that 1150 = P0exp(2 k) and 11500 = P0exp(8 k) we can solve for k and P0. Provide at least five decimal places of accuracy for k and at least two decimal places of accuracy for P0. I've got P0 = 1150/e^2k and P0 = 11500/e^8k but when i try to solve for any variable by...
  44. wolram

    Measuring Red Shift with Accuracy

    We have measures that define the volt, amp, kilo, pressure, etc, etc, compared to these measures how accurate are red shift figures? i know that tolerances are only guaranteed in a machine shop if the temperature is within limits, and all the above can be tested time and time again, but how...
  45. M

    Measuring Accuracy: Quantitative or Qualitative?

    What is the difference between accuracy of a measurement and its level of accuracy? Is the level of accuracy quantitative or a qualitative measure?
  46. U

    Examining the Accuracy of "Moon's Orbit Around Earth"

    hey, can somebody please help me examine the truth of the statement "the moon moves in a near-circular orbit around earth. because the Earth is so much more massive, it own motion is not appreciably affected by the moons presence" ?
  47. U

    Simpson's Rule for Numerical Integration: Accuracy and Applications

    Does the Simpson's rule of numerical integration (\frac{1}{3}h\left( {f_0 + 4f_1 + f_2 } \right)) give exact values for all polynomials to a third degree i.e., linear functions, quadratic functions, and cubic functions? Is there a better method for numerical integration approximation? One...
  48. J

    Iq test accuracy when there's more than 1 logical answer to a question?

    How can iq tests be accurate if people can come up with multiple logical answers to a single question?
  49. I

    Instrument Accuracy: Does Error Remain % or Change to +-V?

    If an electromechanical instrument's (say a galvanometer) accuracy is given as a percentage of its full scale deflection, what would its accuracy be at anything lower than full scale deflection? My thoughts: If say full scale deflection is 100V The error is +-1% which is +-1V, Does that...
  50. brewnog

    How Does a CRT Oscilloscope Compare in Terms of Setup and Portability?

    Anyone got any experience? Don't need anything with the accuracy of a CRT oscilloscope but ease of setup, repeatability, portability and convenience are more important.
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