Test Definition and 1000 Threads

  1. R

    Is force, which we show, right on test charge

    As we draw the electric field lines due to 2 equal magnitude and same nature charges. But when we solve the question concerning the same case we take the resultant of forces due to both charges at a test charge in such a manner that the 2nd charge(let I put the test charge on the left side i.e...
  2. mfb

    I A proposed experiment to test quantum gravity

    Gravity is weak - while we can study the other interactions with individual particles, for gravity we need macroscopic objects to get measurable forces. This makes it easy to measure quantum effects for the other interactions, but hard to do so with gravity. Gravitational forces are always...
  3. J

    MHB What Causes Discrepancies Between Rational Root Test and Modulo p Methods?

    Hi all, I have done the question in two methods. The first method is done by rational root test and the second method is by modulo p (theorem is as attached). It seems that my answers for both methods do not tally. 1. Where have I done wrong in the attached for the methods? Which is the...
  4. R

    Calculating Motion of a Test Balloon on a Methane Planet

    Homework Statement A planet has a gaseous atmosphere with a density of 0.1 g/cm³. The planet itself completely consists of liquid methane with a density of 0.4 g/cm³ and has a radius of 3800 km. A test balloon is dropped onto this planet, which consists of a helium spherical balloon (1 m³, mass...
  5. E

    Automotive Engine explodes during dyno test

    A high-performance diesel engine explodes into pieces while being run on a dyno test.
  6. binbagsss

    A Why Scalar Quantities Matter in Singularity Tests

    Apologies if this is a stupid question, so for e.g, in a Schwarzschild space-time we look at ##R^{abcd}R_{abcd} ## (we seek some scalar quantity that blows-up and can not use ##R##as we are looking at vacuum solutions so we know this is zero) The reason we seek a scalar is because it is the...
  7. SemM

    MATLAB Making a short test for self-adjointness

    Hi, I made the following command in MATLAB to test for the following: \begin{equation} \langle T\psi,\phi\rangle=\langle \psi, T\phi\rangle \end{equation} %Self-adjoint test syms x a = (diff(exp(-x^2)))*exp(-2*x^2) b = (diff(exp(-2*x^2)))*exp(-x^2) W = int(a, x) P = int(b, x) O=W-P and it is...
  8. T

    Can Medical Tests Determine My Body Energy and Motivation Levels?

    Hi I would like to know if there is any physical or medical scientific tests I can take to know/confirm my energy levels/body energy levels and will level when it comes to motivation. the reason for wanting to take these tests is that I have a severe mental brain neurological disability known...
  9. M

    Liquid volume loss during pressure test

    Hi, I'm doing a pressure test with a liquid medium. I have a fixed volume and I know the pressure drop, and temperature change - how do I calculate volume of liquid lost in a leak?
  10. Mentz114

    I Can Exact Joint Probability Distributions Predict Violations in CHSH Tests?

    I've spent some time setting up my simulation of a photonic EPR experiment and came up with an exact joint probability distribution for the outcomes ##P_{xy}(\alpha,\beta)##. To calculate the CHSH number we need the probability of a coincidence for each of the possible settings which becomes a...
  11. T

    Wilcoxon Sign Rank Test rejection region

    Homework Statement Two computer software packages are being considered for use in the inventory control department of a small manufacturing firm. The firm has selected 12 different computing task that are typical of the kinds of jobs. The results are shown in the table below. At the 0.05 level...
  12. T

    Distinguish between sign test and Wilcoxon signed rank test

    Homework Statement I know that for both method are used to test the 2 group sample for a non-normally distributed population ... But , i am not sure the difference between them . Can someone explain the difference between them ? When to use sign test and wilcoxon signed rank test ? Homework...
  13. T

    Is a Two-Tailed Test Appropriate for Analyzing Plant Position and Seed Count?

    Homework Statement In the photo above , H0 = the position of the plant doesn't affect the number of seeds in the pods . H1 = position of the plant affect the number of seeds in the pods The Attempt at a Solution This is a two -tailed test , am i right ? Referring to the normal distribution...
  14. binbagsss

    I Function of 2 variables, max/min test, D=0 and linear dependence

    ##f(x,y)## a critical point is given by ##f_x=0## and ##f_y=0## simultaneously. the test is: ##D=f_{xx}f_{yy}-(f_{xy})^2 ## if ##D >0 ## and ##f_{xx} <0 ## it is a max if ##D >0 ## and ##f_{xx} >0 ## it is a min ##D >0 ## is is a saddle if ##D =0 ## it is inconclusive, and ##f_x## and...
  15. C

    How to test toroidal permanent magnet with inside field

    As the permanent magnet is magnetized by donut shape coil, thus field B = 0 outside. How can I know if seller screwed me or not?
  16. Arman777

    Series Comparison Test for Divergence: sin(1/n) vs 1/(1+n)

    Homework Statement ##\sum _{n=0}^{\infty }\:\sin \left(\frac{1}{n}\right)## Homework Equations The Attempt at a Solution Can I try comparison test by ##\left(\frac{1}{1+n}\right)<sin\left(\frac{1}{n}\right)## since ##\left(\frac{1}{1+n}\right)## diverges also...
  17. Dusty912

    Applying hypothesis test data collected (Statistics)

    Homework Statement So I am doing a project for statistics and wanted to apply a hypothesis test to see if there is a correlation between the number of years spent at my college and the number of services used. The services include library, recreational services, clubs, etc.. i sent out a survey...
  18. N

    Indentation Test: How can you tell if the material yielded?

    Homework Statement I am modeling a 2D indentation test of pure Aluminum in ANSYS using non-linear analysis. The objective is to determine the minimum force required at the rigid indenter in order to achieve yielding of the Aluminum block. The indenter is 2 micrometers in width and is rigid...
  19. evinda

    MHB Test whether the integer is a prime

    Hello! (Wave) We want to find an efficient algorithm that checks whether an odd number is a prime or not. In order to obtain such an algorithm, one tests the congruence $(X+a)^n \equiv X^n+a$ not "absolutely" in $\mathbb{Z}_n[X]$, but modulo a polynomial $X^r-1$, where $r$ have to be chosen in...
  20. M

    MHB How Do You Calculate Sample Size for a T-Test with a 95% Confidence Interval?

    i am stuck on question 12 I am trying to use the hypothesis testing 1 sample t test formula . the right answer is 338 but I can not get this
  21. D

    LaTeX Preamble for setting up a latex/pdf for homework or writing test.

    I use this when making exams for all my courses. It goes in the preable or the very beginning of the .tex file. Note the use of the commands, I also include commands imported by the file macros! Macros is simiply a .tex file defining your own commands. I have included in another post a list...
  22. M

    Why Assume Limit of \( S_{n-1} = S_n \)?

    Homework Statement If the sum of a sub n to infinity (n=1) converges then the limit of n as n tends to infinity of an = 0 Homework EquationsThe Attempt at a Solution an =(a1+a2+...an)-(a1+...+an-1) = limit of an (n tends to infinity) = sn -s(n-1) =0 The area I'm confused is why do we assume...
  23. starstruck_

    Testing How Can I improve my test taking?

    Hi! I’m a physics undergrad and one of my first term courses is applied linear algebra. I knew exactly what to study for this midterm, so I practiced it over and over again until I was sure I was comfortable with it- went into the test and the exact same type of questions I studied and...
  24. Q

    Calculation of the net force on a test charge

    Homework Statement Homework Equations \overrightarrow{F} = \frac{1}{4\pi\epsilon_0}\frac{qQ}{r^2}\hat{r} The Attempt at a Solution I found to hard summarizing all forces directly adding each to other. The solution of this problem is only matter of drawing the 13-sided polygon and forces...
  25. S

    What causes color change in powders during XRD testing?

    I was performing XRD earlier, and I came across this odd occurrence in the powders that were being inspected - After it was performed, the crystalline powder I had been testing had gone off color into this yellowish appearance (Originally was white). Upon disturbance, the powder become white...
  26. N

    Testing Struggling with Physics: Am I Cut Out for This Major?

    I feel way in over my head. I've been telling people I'm going to major in physics, but I've actually never taken a physics course before. This is my first one. I was so excited to start this class, start the major. I was so excited about research and internships and what I'd be able to do with...
  27. A

    MBTI type (Myers-Briggs Type Indicator) -- Jung Typology Personality Test

    I always keep on taking the MBTI and I get INTP. What is everyone else's MBTI? http://www.humanmetrics.com/cgi-win/jtypes2.asp << Mentor Note -- INTP = Introverted iNtuitive Thinking Perceiving >>
  28. R

    A F-test regression test, when and how?

    I am aware that f-tests can be used to check the null hypothesis when comparing regression models if the models are nested. What I am confused about is if I can apply an f-test to compare the following, (and if so what is the best way) I have two regression laws Y = a1*X1 + a2*X2 + b Y =...
  29. M

    Classical What Textbooks are best for self-study for SAT Physics Test

    I am planning on taking SAT Subject test in Physics in few months, but I don't know which textbook is best to study all physics concepts that will be tested. I have a basic knowledge of algebra and almost none of calculus, as they didn't teach them back in high school, but I really want to...
  30. Eclair_de_XII

    Force on a test charge due to two point charges?

    Homework Statement "Let there be two point charges ##q_1=3.5μC## and ##q_2=-3.5μC## located at ##(0,0.3 m)## and ##(0,-0.3 m)## respectively. What force do these two charges exert on a test charge ##Q=4.5μC## at ##(0.4 m,0)##?" *title should read "due to two point charges"* <Moderator's note...
  31. B

    Automotive NVH Test for rubber mounts on firewall

    Hello gang! I am dealing with a new issue at work and I though you might give me some much useful insight. Im trying to fix a component to a plate and using 4 screws and rubber bushings to attach said plate to the firewall. The component is around 5-6 kgs and needs to held in place firmly but...
  32. H

    Easy way to test for Fusel Alcohols in ethanols

    I know fusel alcohol is not an official term, and my chemistry is rusty, but is there an easy way to test for fusel alcohols in a primarily ethanol/water mixture? Basically, any alcohol that isn't ethanol? https://en.wikipedia.org/wiki/Fusel_alcohol
  33. A

    B Visual Pattern Recognition Test

    Dear moderator, if the thread is irrelevant to this forum section, please move it to the right section. Thanks.
  34. morrobay

    Lab Test For White Ginseng % Purity?

    Can anyone test for or give reference for lab testing white ginseng % purity? I can send sample by mail. Thanks, morrobay
  35. T

    MHB Probability Value Question (left-tailed test)

    I have a statistics problem that is probably not too difficult for someone who knows what they are doing, but I still need help with it. Here’s the scenario. There is a town with a highway built at the end of 2013. The mayor is concerned because of the number of traffic accidents on the...
  36. A

    Electromagnetic Ring Expansion Test

    If my professor tasked me with finding out where to find the materials for setting up an electromagnetic ring expansion test, where is a good place to start? Generally, what is a good procedure to follow when setting up an experiment? I am not very experienced but I would like to learn. The...
  37. C

    B General Relativity Aces a Test at Supermassive Black Hole

    General relativity passes test at Milky Way’s central black hole by Ken Croswell For the first time, astronomers use stars orbiting a supermassive black hole to test Einstein's general theory of relativity, finding no sign of a fifth fundamental force. Links: John Batchelor Show...
  38. M

    MHB How Can You Test for Symmetry in Mathematics?

    Test for symmetry about the x-axis, y-axis and origin. | y | = 2x - 4 What are the rules for testing for symmetry?
  39. M

    MHB Is y = | x | - 2 Symmetric About the x-axis, y-axis, or Origin?

    Test for symmetry about the x-axis, y-axis and origin. y = | x | - 2 What are the rules for testing for symmetry?
  40. Anshul23

    Testing I couldn't take AP test; what's the probable aftermath?

    I am a high school graduate from India ( GPA of 4.8 out of 5), and I am planning to go for a physics major.I got an admit at the University of Massachusetts Amherst with a good scholarship and all but I recently found that most of my friends in the States had already taken an AP exam which I...
  41. K

    MHB How to calculate p-value from KS test?

    I've got these tests They show the growth of a plant in mm and I have to test if the growth is superior to 1.1mm I think I have to get the p-value from KS test but I'm not seeing how
  42. E

    Does Surface Preparation Affect Tensile Strength in ASTM E8 Tests?

    Hi, I'm performing tension tests using a dog-bone specimen conforming to ASTM E8 on 6061-T6 extruded aluminum alloy. ASTM E8 says the surface preparation should be as the product specified. The material I ordered is low grade bar stock 2" wide by 0.25" thick. If I am going to reduce the...
  43. I

    Other USAPhO test -- When should I be able to answer these questions?

    Hi, I wasn't too sure what forum to put this question in, so I apologize if it is in the wrong one. I have been looking at the past exams for the USA physics olympiad ( https://www.aapt.org/physicsteam/2016/exams.cfm ). I have been pretty good with the fnet=ma exams, but when it comes to the...
  44. D

    I Use a level to test the Earth's curvature?

    So, I'm sure many of you have seen the experiment recently by a flat-Earth member who brought a level on a plane with him in order to determine whether or not the Earth is flat or round. And yeah, my immediate thought was similarly "how silly!" But it did make me wonder: Could you do it that...
  45. e2m2a

    I Test for inconsistency of system of nonlinear equations

    Is there a quick test to determine if a system of nonlinear equations is inconsistent. For example, suppose there is a system of equations such as: 3x cubed + 2y cubed = z cubed 2x cubed + 5y cubed = z cubed Since these two equations are clearly not dependent, could we say that since...
  46. G

    Static test of Denso 12 V alternator

    I know a real test of this unit would be to mount it and run, checking DC and AC voltage, current etc. The plan is to mount it on my Super Dexta, but this would need some work as there's currently a dynamo which is starting to fail. I was given the alternator free and would like to bench test it...
  47. F

    Consolidated undrained vs unconsolidated undrained test

    Homework Statement In the consolidated undrained , why there's only increase in pore water pressure due to deviator stress application ? Why in unconsolidated undrained test , why there is both increase in pore water pressure due to deviator stress application (ud) and also uc ? Homework...
  48. F

    Consolidated drained triaxial test

    Homework Statement This is the problem regarding with Consolidated drained triaxial test . I have uploaded some photos here . The first photo is from my notes . While the 2nd until the 3rd photo are from my refernce book . Homework EquationsThe Attempt at a Solution In the first photo , I don't...
  49. T

    Which chromatography test fits best?

    Homework Statement A purified protein fraction containing buffer with salt can be desalted by one of the following techniques: (1) Gel filtration chromatography (3) Paper chromatography (2) Affinity chromatography (4) Thin layer chromatography2. The attempt at a solution Well, the analyte...
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