Test Definition and 1000 Threads

Homework Statement Data from the short-circuit test of a 60-Hz, 100-kVA, 4600–230-V transformer are: VSC = 172.3 V ISC = 20.2 A PSC = 1046 W Get the per-unit parameters. 2. Relevant equations ISC ≠ Irated, so how will I solve the problem? The problem is from the book with ISBN 0130612103.

Homework Statement Determine whether the series is converging or diverging Homework Equations ∞ ∑ 1 / (3n +cos2(n)) n=1The Attempt at a Solution I used The Comparison Test, I'm just not sure I'm right. Here's what I've got: The dominant term in the denominator is is 3n and cos2(n)...

Homework Statement [/B] 1. After a long road trip during summer break, a college student wants to estimate how long she drove between rest stops. She takes a random sample of 15 stops and records this data in hours: 1.5, 2.6, 1.75, 3.5, 2.25, 3.75, 1.8, 2.9, 3.2, 3.15, 1.5, 2, 3, 2.75, and...

Is anyone interested in a GRE Math Subject Test study group in the Milwaukee area that meets up to 3 times or so per week?

I am looking for suggestions pertaining to preparation for the GRE Math Subject Test. I plan to take it around fall semester. Which text preparation books are the best?

Hello, has anyone here had anxiety issues when taking tests before and noticed a difference in performance after taking medication? I have pretty bad anxiety before my exams, and find myself making very little mistakes that still show I understand the material. For example, when asked to...

As I am sure everyone is aware, there are still folks who don’t believe SRT and GRT. While 99.9% of them are nut-jobs, there is at least one that I respect – Tom Phipps specifically. I am not familiar with any of his writing before the advent of the GPS satellites. In any case, he now accepts...

Homework Statement [/B] This is the question I have (from a worksheet that is a practice for a quiz). Its a conceptual question (I guess). I understand how to solve ratio test problems. "Is this test only sufficient, or is it an exact criterion for convergence?" Homework Equations Recall the...

I'm working on the following problem and I have made it this far... am I on the correct path or am I doing this incorrectly?? I find series extremely confusing. Also... how do I find the error involved in the improved approximation? This is the series I am working with...

What are the different ways to detect harmful chemicals in food? I need to find at least 5 tests for different chemicals for my chemistry investigatory for my final exams. I have only chemicals available in a standard lab in my hand.

Hello my name is Mike Moore and I work for Copperhead Industries, LLC We are a tracer wire manufacture for the underground non-metallic pipe utility sector, natural gas, water, sewer and telecom. We use magnesium anodes for grounding out the far end of the tracer wire system which completes...

c2h6 = c2h4 + h2 c2h4 = c2h2 + h2

Homework Statement I'm reviewing for a test and working on the practice problems for the ratio test that Pauls Online Notes gives. So here is given problem: Here is his solution for the problem: 2. The attempt at a solution I worked this out before I looked at the solution and I got it wrong...

i am asking is it possible to apply scientific methods to stop the syrian war , or it is just too much away from reality and real life note : i am from syria and this question is not making me sleep at all ...

Hi everyone, I'm currently taking Calc II course and I'm kind of stuck in this ratio test proof thing. Homework Statement http://blogs.ubc.ca/infiniteseriesmodule/appendices/proof-of-the-ratio-test/proof-of-the-ratio-test/ I'm trying to understand the proof, but there are some parts that I...

Hi all, I want to measure the concentration of benzene or toluene, in water with a GC, FID detectors. I put benzene in water with an adsorbent and after hours I've to test the concentration of benzene. In the lab we've already methanol and toluene, so I'm thinking to use toluene as pollutant...

Hello, I need to replicate the conditions of a clutch on a pin on disc tribometer to measure the coefficient of friction. However the tribometer I have access to can't spin faster than 1000 RPM. The clutch will reach speeds from 3000 RPM to 9000 RPM. I calculated the normal force required on...

Homework Statement So the test is to take the determinant (D) of the Hessian matrix of your multivar function. Then if D>0 & fxx>0 it's a min point, if D>0 & fxx<0 it's a max point. For D<0 it's a saddle point, and D=0 gives no information. My question is, what happens if fxx=0? Is that...

Dear all, this may seem like attention-seeking of some sort but recently I competed in my country's Physics Olympiad and vastly under-performed. It may sound like I'm making excuses but I largely attribute this to a panic attack I had at the start of the test that led me to be unable to perform...

Hello I'm taking linear algebra and have a couple of questions about linear independence, spanning, and basis Let me start of by sharing what I think I understand. -If I have a matrix with several vectors and I reduce it to row echelon form and I get a pivot in every column then I can assume...

I got a 61% on my first mathematical methods for physics and engineering test. I thought I would at least get a solid C on that test :( If I were to receive a 100% on everything thing else ( 1 test , 1 final, 5 homeworks) I could end up with a 92.5% in the class. After that test I currently...

Let's say a radio power transformer or other electronic transformer (audio for example) has a short between two of its coils (for example, the enamel coating has burnt off). Is there any way to test it to find out without taking it apart? As I see it the short will be either between adjacent...

Hello everyone, A few weeks ago I got a test about physics. One of the questions on the test was about a satelite that would go to an other planet, it was doing system tests in orbit, we had to tell if the satelite had weight. I understand it doesn't, because it is falling and so doesn't apply...

We manufacture materials of various types and hence target thickness. This is a continuous process, and material is cut to specified lengths (often over 10, 000 meters) after production. To control the process during production, we take regular measurements of the thickness (Which is the key...

Hi all, My friend and I have created a homemade supercapacitor. It can power a LED light and small alarm clock. We charged it up to 1.5 Volts. I was wondering if anyone knew how to find the exact capacitance in Farads, any help will be appreciated. I have added the steps that we have taken in...

Hello, I am analysing a 3D D shaped Incompressible Neo hookean material in contact with a semi cylinder using Ansys 14.5 APDL. The input values provided are C10=2737674.313898 and mass of D shape geometry to be 8 kg/m. I have converted these values into density and Shear Modulus as required in...

I am a HS math teacher, in the coming months, I was told I will be taking over some physics classes. Although I am also certified in physics but I never taught physics before. So here is my question: Do you know of any physics test generator software out there? To give you an idea, for math...

Hi, let ## r_1,..,r_n## be residuals in a given regression. I am trying to understand how the test for normality works. This is how I think it works: We take the sampling mean , i.e., ##r:=\frac {1}{n} \Sigma r_i / n## , and the sampling standard deviation ##\sigma_{r_i} ##. Then, if the...

I have to test treatments B,C,D and E where ##H_0:\mu_B=\mu_C=\mu_D=\mu_E## vs ## H_1: not H_0##. Use ##\alpha=0.05## given this problem. Now ##\mu_A## is not included in the hypothesis so I am trying to figure out how to go about this problem. I was thinking of using orthogonal contrasts and...

Homework Statement Ok, so I've read many of the threads on here and they all say the same thing. I think I understand the Gauss Law and the theory behind the spherical shell. The question is this: Find the WORK done bringing a test charge q from infinity to the center of a spherical shell of...

Hello, Do you guys know any website from which I can download a lot of grade 12 bio quiz (and test) questions with the answers?

Hi, physics undergrad here with bad statistics skills! I'm working on my 3rd year project and I need to do some statistical analysis. First, I'll paint the scene: We have a number of tables, each of 10,000+ sources taken from the space telescope Herschel. They have had their flux measured at...

I'd like to see for myself the Equivalence Principle. Would there be a commercially available test kit like perhaps a small iron and cotton enclosed in vacuum tubes and they are to fall at same time and hit the bottom at same time with indicator lights to tell if they hit at same time or at bit...

Homework Statement A stone is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of 45◦ . With what speed was it thrown? Homework Equations g=9.8 projectile motion is symmetric The Attempt at a Solution I got the answer 277.539 by treating this is a...

Homework Statement A locked rotor test is performed on a permanent magnet DC machine with the following results: Terminal Voltage 5 V DC Input Current 10 A DC Locked rotor torque. 20 Nm a) Making suitable approximations deduce the effective rotor resistance in ohms? b) Making suitable...

((2+i)/(3-4i))^(2n) I know it converges with 1/5 < 0 but I don't understand how to obtain 1/5 unless somehow its like this (2+i)^2 = (4+1)=5 (3-4i)^2 = (9+19)=25 which is 5/25 which is 1/5 but that doesn't seem like the correct way to me

Hello There! Can I have some tips for taking ACT. I took for the first time and got 26, can y'all tell me how I can get it into 30's?

Homework Statement A short circuit test is performed on a small single phase transformer. The results are: Primary Voltage 5V, 60Hz Primary Current 2A Secondary Current 10A Primary Power 8W a) Making suitable approximations deduce the primary/secondary turns ratio (single number)? b) Making...

Homework Statement So my question was Sum- (n=2) ln(n)/n Homework Equations I noticed that you can only limit comparison, because so far, I have tried doing all the other test such as the nth term test, p-series, integral(i have no idea how to integrate that). The Attempt at a Solution

I have a heat exchanger with water/air as medium and we test it in a facility where we cycle the water temperature between 25 to 95 degrees Celcius with a cycle time of 5 minutes for thermal fatigue. Our customer require the testing to be between 5 to 95 degrees instead with 3 minute long...

Homework Statement http://www.solutioninn.com/physics/electricity-and-magnetism/magnetic-fields/particle-with-charge-2.15uc-and-mass-3.20-x-10-11-kg-is I am just going to link this because I don't know how to draw a nice diagram like that and put it here. But essentially that is the question...

Hi, I have a 4x4 contingency table that by visual inspection looks approximately symmetric, in the sense that for each entry aij we approximately have a_{ij} = a_{ji} for i,j=1,2,3,4. I would like to know how can I perform a statistical test for symmetry. An attempt I made was to treat the...

I have never taught an AP class, and this year is my first year where my students will be taking the AP Physics 1 test. I took a look at the sample questions they have released and it got me scared and nervous. What are you doing to prepare your students for the AP test? Anything different...

I've found several accelerometer apps for smartphones (for example http://www.iseismometer.com and http://www.now-instruments.com/products/3-vibsensor ). Are these useful for doing quantitative vibration analysis, and if not, what are their deficiencies?

In my textbook it says if you are comparing limn->infinity of an/bn an>0 and bn>0 for the limit comparison test to apply. It says nothing about "an" having to be greater than "bn", so as long as both are positive for each term I can use the limit comparison test right? It isn't like the...

Hey Guys! I am working on a math project and I am stumped. I'm not sure weather I should use the chi-squared test or another test with my set of data. I am testing weather there is a relationship between crime rates and the unemployment rate of cities. Could someone please help? I'm not testing...

Homework Statement Use the limit comparison test to prove convergence or divergence for the series sum from n=1 to infinity for ((5n^3)+1)/((2^n)((n^3)+n+1)) Homework Equations The limit comparison test says that if you have two positive series, sum An and sum Bn, let C=lim n to infinity of...

Homework Statement Use the limit comparison test to show the series converges or diverges: Sum from n=1 to infinity of ((5n^3)+1)/((2^n)((n^3)+n+1)) Homework Equations suppose Sum An and Sum Bn are two positive series. Let lim as n goes to infinity of An/Bn = c: 1) if 0<c<inifinity then either...

The question asks whether the following converges or diverges. \int_{0}^{\infty } \frac{\left | sinx \right |}{x^2} dx Now I think there might be a trick with the domain of sine function but I couldn't make up my mind on this. I tried to compare it with 1/x^2, (sinx)/x, and sinx. I actually...

Homework Statement Use the limit comparison test to check for convergence or divergence: Sum from n=1 to infinity of ((2n)^2+5)^-3 Homework Equations let lim n to infinity of An/Bn = c 1) if 0<c<infinity then either both converge or both diverge 2) if c=0 and sum Bn converges, so does sum An...