Test Definition and 1000 Threads

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...

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...

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...

\int_{0}^{\infty} \frac{x^2 dx}{x^5+1} The question asks whether this function diverges or converges. I have tried to do some comparisons with x^2/(x^6+1), and x^2/(x^3+1) but it didn't end up with something good. Then I decided to compare it with \frac{x^2}{x^4+1} Since this function...

Homework Statement Use the integral test to determine if this series converges or diverges: sum from n=1 to infinity of n/(1+(n^2)) Homework Equations Integral test: a series and it's improper integral both either converge or both diverge The Attempt at a Solution see attached - I need help...

Homework Statement I'm taking my first basic physics course and I came across this simple question (which I got the wrong answer apparently). The question was this: what is the velocity and acceleration of an object which has reached it's maximum height after being thrown directly upwards...

Hi, It's been a while but from what I remember when you short circuit a transformer, electrically it's like you've series'd up the coils and shorted the magnetisation branch. And when you open circuit a side of the TX it is like the current flows through a side then through the magnetisation...

I know it follows a geodesic in space-time, but is it not being able to bend space-time itself, part of the definition? When I google i just find 'follows a geodesic in space-time'. I thought that it also should not bend space-time itself - but this isn't included in the definitions I've...

Why test tracks are banked parabolic why not elliptical or circular or hyperbolic? what are advantages of parabolic curve over another curves?

Homework Statement Show if this sequence (with n=1 to infinity) diverge or converge Homework Equations [/B] The Attempt at a Solution If I use the Limit Comparison Test: compare with so you get that equals lim n -> inf => inf. Can I use the Test like this? What does this...

Hi, I don't know if this is the best place to post thia, but I'll give it a try :-) I'm taking the SAT subject tests physics, math level I and level II, and the ACT test thia coming year. As I'm not following a high school curriculum, and am merely studying on my own, I really have no idea of...

Hello, I recently came into an issue in regards to my course schedule. I talked to one of the professors in the math department and suggested I not take 3 science classes as well as math 295 (hardest math sequence my school has to offer). This puts me at issue in regards to meeting the math...

Ill be attending a masters program this spring semester and they require a Placement test. I am wondering what's the best way to get back in the swing of things.? any good suggestions?

I have a question considering the transformer's short-circuit test and the impedance (or short-circuit voltage). The transformer's general data is: Rated power: 50kVA Primary voltage: 10000V (10kV) Secondary voltage: 420V (0,42kV) Primary current: 2.89A Secondary current: 68.73A Vector group...

Hi Everyone, I am building a hydro turbine, I am expecting it to produce circa 4 kw possibly as high as 7 kw depending on flow. I am on a very limited budget. Please could you suggest possible means of getting load output data? I have considered attaching a heavy truck 24 v alternator and doing...

http://online.wsj.com/public/resources/documents/2014_1113_dougwilliamsindictment.pdf Mr. Williams is being charged with fraud for showing a machine and technique for being a fraud. Mr Williams is not being deceptive during a test, the person being 'tested' might be but that's the problem of...

Homework Statement When using the Integral Test do you need to change the bounds to n+1 and n-1 for an increasing and decreasing function respectively? This is a question that comes up when using the integral test. I think that you just use the original bounds for the integral. We are a bit...

Homework Statement [/B] From K=4 to infinity the Σ (-1)^k (k/e^k) Converge or diverge? Use: a) Ratio Test b) Root Test c) Integral Test d) Alternating series test Homework EquationsThe Attempt at a Solution For the alternating series test and ratio test I have the correct answer that it...

Background: Physics Major (3.5 physics gpa), college graduate, pursuing PhD, PGRE: 700 52% I have seen a couple of threads on test taking, but I have a slight different direction. I don't have problems with tests in general. I have done well on many many exams ( physics, math, chemistry...

Homework Statement ∑ x2n / n! The limits of the sum go from n = 0 to n = infinity Homework EquationsThe Attempt at a Solution So I take the limit as n approaches infinity of aa+1 / an. So that gives me: ((x2n+2) * (n!)) / ((x2n) * (n + 1)!) Canceling everything out gives me x2 / (n + 1)...

Homework Statement Crash Test Craig drives his 800kg car up a 100m ramp that is at an angle of 35 degrees above the horizontal. The car exerts a forward force of 12000N and the force of friction between the ramp and the car is 20N. He is trying to jump over a series of spinning helicopter...

I recall reading that, while it is not true for all fields, there is a correlation between standardized test scores and academic performance in math and science. I did a quick search, but couldn't find much information that was specific to math and science. I teach AP Calculus and this subject...

Homework Statement Refer to Table 2.11. 10.6 What significance test can be used to assess whether there is a relationship between receiving an antibiotic and receiving an antibiotic culture while in the hospital? Here's my attempt of recreating the table: \newcommand\T{\Rule{0pt}{1em}{.3em}}...