Intro Definition and 563 Threads

Ive been working all afternoon on these two problems, and i don't have a clue how to solve either of them. Homework Statement Let p>2 be a prime number and let n=2p +1. Prove that |2|n =2p. Let p > 3 be a prime number and suppose there is an integer a such that a2+a+1 ≡ 0 (mod p). Prove that...

I just started work in the lab and I'm finding myself having to build lots of circuits. Only problem is I have never studied these before ever, and don't even know the basics really. Can anyone recommend a concise intro to electronics which covers all the things I should know but not the things...

Homework Statement Look for a matrix that has row sums 4 and 8, and column sums 2 and x: matrix = [a, b] -------I don't know how to do latex [c, d] a + b = 4; a + c = 2; c + d = 8; b + d = s; The four equations are solvable only if s = ____. Then find two different matrices that have...

Despite the fact that QED is so popular, i have a hard time finding a good introductory book about it [ except feynman's of course;-) ]. Do you have any good recomendations?

Hi all, I recently was posting in another thread on how to properly integrate the equations of motion in gravitational simulations. I thought this would be a good opportunity to provide some basic knowledge on simulations, numerical differential equations, and a little bit of programming. I'm...

Hey, I'm in first year engineering (mechanical), but we study EE as well. I've got exams coming up in about 2 weeks, and I need a good intro text to help me study since the lecture notes I have aren't really adequete. The kind of stuff I'm covering include circuit theory (thevenin problems...

urgently needed help on intro physics... This is my first time posting on here so I hope someone will answer my questions. Here they are: 1. A scientist testing a material discovers that when a voltage of 10V is placed across a material a current of 10A flows. When a voltage of 20V is...

Homework Statement hey, it's been on my wish list for some time, i have decided to teach my self diffrential equal, rather than waiting to be taught at school, after having some exposure through vibrations and circuits. so i got a book and i started to learn, the question came to be...

These two courses seem like they would be identical aren't they ? How is chemistry 1 any different at all?

Two friends and myself are going to start doing research with a professor of ours on Haar wavelet transforms. I was curious if there are any texts or any online resources which those of PF would recommend? So far the three of us have completed Engineering Calc I, but the professor feels...

I CANNOT POST IN THE SCIENCE BOOKS AND MATERIALS SUB FORUM FOR SOME UNKNOWN REASON. Now that that is out of the way, I am in dire need of assistance. I will be taking classical physics I and II this coming school year, and I have very poor physics background. I didn't even take high school...

I have pretty good handle on non-relativistic quantum mechanics, but I would like to learn about the Standard Model (Quantum Field Theory). What is the best introductory book and/or introductory article on QFT? Thanks Here are some I've heard of: Articles "[URL Model: An Introduction Authors...

Hi guys and gals, Stumbled across this forum via google. Quick introduction: I'm not involved in cosmology at all. But I do have a casual interest in it, simply because it inspires me. I'm in my mid 30s, mechanical design engineer, atheist bordering on anti-theist, but that could simply be...

Homework Statement A surface at z = 0 is held at potential V (x, y) = V0 cos(qx) sin(qy). Find the potential in the region z > 0. Homework Equations Laplace's equation in Cartesian coordinates The Attempt at a Solution I wrote at least a page of my past 2 attempts at a solution...

Homework Statement Reviewing for a midterm. I have this problem I can't seem to nail. Want to try it? "The acceleration of a particle moving only in a horizontal xy-plane is given by a=<(3t)i,(4t)j>, where 'a' is in m/s^2 and 't' is in seconds. At t=0, the position vector r=<(20)i,(40)j>...

Hello everyone- I was wondering if anyone could recommend introductory books on particle physics? I'm looking for something an undergrad could read as if they were taking a beginning course. I've searched Amazon and found tons of college textbooks only I'm not sure which ones are...

Homework Statement Let f(x) be a twice differentiable function on an interval I. Let f''(x)>0 for all x in I and let f'(c)=0 for some c in I. Prove f(x) is greater than or equal to f(c) for all x in I. Homework Equations Mean value theorem? The Attempt at a Solution f''(x)>0...

I'm looking for an introductory neuroscience book. I only know basic biology so I'm not sure if I'd be ok in reading a textbook (I do have the whole internet though if I come across something unfamiliar). I've seen several books however they seem geared for medical students instead of actual...

[b]1. The star Alpha goes supernova. Then ten years later and 100 light years away, star beta goes supernova. Aliens passing by observes that the explosions occur 120 light years away. According to them, what is the time between the explosions? [b]2. So I think I am supposed to used the...

A boy tosses a coin straight up to 2.8 m. Suppose the height when the coin leaves his hand is 1.2 m. What was the initial speed of the coin when it left his hand? I'm just confused as to what equation to use. And I don't know whether to assume the acceleration is -9.8 m/s^2. Thanks.

Homework Statement If S\subsetR is finite and non-empty, then S has a maximum. Can someone look over this? I struggled a bit in my first proof class, which is why I am asking for help, so I really am unsure if this is right at all. Let S={1} So 1\inR such that for all x\inS, 1\geqx So...

For 0<x<y, show that x<\sqrt{xy}<1/2(x+y)<y I have no difficulty showing that x<\sqrt{xy} and 1/2(x+y)<y. I am having difficulty with \sqrt{xy}<1/2(x+y). x<y xx<xy x^{2}<xy x<\sqrt{xy} and x<y x+y<y+y x+y<2y 1/2(x+y)<y

Well, I got a D grade on my intro physics final, which means i got the credits for the course, but my gpa has dropped down a few points. My teacher is not to blame but he sure didn't help either...he has a passion for the subject, but not for teaching. Anyway, I guess i should take it...

Repeating "Intro. Physics." I am in my late 30's, and I have an exam this Saturday on "intro. physics." What I have found is that I enjoy Physics when I learn at my own pace rather than under the structure and (what I perceive to be) rigid time constraints of the University environment. I find...

How much force is necessary to lift a ring, diameter 20mm, made of fine wire, and placed on the surface of water at 20 degrees celsius? All the equations from the chapter: Shearing stress = F/A = Viscosity*(velocity parallel/h) Kinematic Viscosity = viscosity/density Change in pressure =...

I'm taking this class and so far we have learned very basic stuff. The chapters that we learned so far are: 1 binary systems 2 boolean algebra 3 gate level minimization 4 combinational logic 5 synchronous sequential logic we have to write a 5 page paper on "applications of what we...

Homework Statement The Michelson interferometer can be used to measure extremely small distance scales. What is the smallest distance scale that can be measured? What uncertainty is associated with this? What is the smallest scale that can be measured by the Fabry-Perot...

Hello, I'm in my 30's and haven't been studying algebra, trig, or physics for around 19 years. Well, i just failed my second physics test and I'm pretty bummed out about it. However, I was thinking of taking the same class again next semester, but I'm not sure if i will do any better the second...

How did you guys like your intro to bio textbooks? What was your favorite and why?

I'm taking a course in dynamical systems and I'm struggling to grasp some of the concepts. The instructor only occasionally reference the textbook I'm using, which is Differential Equations, Dynamical Systems, and An Introduction to Chaos 2nd Ed. (By Hirsch, Smale, and Devaney). I'm looking...

What is the best review article, published in a peer-reviewed journal, introducing string theory?

Hi, I've got a problem with the following problem. This is 1.8 out of Griffiths QM text, and was previously covered on this forum for another user in https://www.physicsforums.com/showthread.php?t=152775", although that thread doesn't address my problem. 1. Suppose a constant potential...

I'm almost finished with my first years of physics and I've noticed a few things. Granted each school is different but people out there with some more insight can perhaps clarify. 1. Even for an interested student of physics there seems to be far too much material covered over these courses...

Which book/books are a good intro into manifolds? Maybe a book that is both oriented towards a physicist but also includes rigor. How is this book An Introduction to Manifolds by Loring W. Tu In the preface it says one year of real analysis and a semester of abstract algebra would suffice as a...

Hello guys, can you please help me figure out how to solve this problem. Many thanks! A scanning He–Ne laser that scans at a rate of 10 s−1 emits 5 mW through an aperture of 0.7 cm. If the beam divergence is 5 milliradian, then, for an intrabeamviewing distance of 200 cm, calculate (a) the...

I'm not sure if this is the right forum, but I'd like to know: What's a good physics text that uses calculus? I mean, not just uses calculus in the definitions of velocity and acceleration and whatnot, but uses it in almost all the problems? I find my current text, "Fundamentals of Physics" by...

Today I failed my intro Physics Test...I got 24%. This test is worth 20% of my final overall grade...so I'm really quite bummed out about this. I've been studying hard...I guess it's because I'm in my 30's and haven't been in school doing Physics for around 15 years. Anyway, anyone have...

I have posted a problem below and my attempt could someone please tell me if I am going wrong and where. Thanks An automobile of mass 650 kg is acted on by a net force (F) given by F = 800 - 40.0t, where t is in seconds and F is in Newtons. At t=0, the velocity of the automobile is 5.00m/s...

Homework Statement If the functions f and g are defined so that f'(x) = g'(x) for all real numbers x with f(1)=2 and g(1)=3, then the graph of f ad the graph of g: Is the answer that they do not intersect? The other choices are: intersect exactly 1 time intersect no more than 1 time could...

Homework Statement Suppose that x0\in (-1,0) and xn=\sqrt{xn-1+1} -1 for n\inN. Prove that xn\uparrow0 as n\rightarrow\infty. the formatting is odd so read outloud, the function for x sub n is "x sub n equals sqrt(x sub (n-1) + 1) -1. If it is still unclear, ask and I can post an image...

Homework Statement Assume 50 W of power is used to perform each of the following tasks (one at a time). a. Lifting 1000kg (1 ton) by one meter. b. Lifting 1 g (0.001kg) by one meter. (Hint: What is the potential energy gain by the object?) How long would it take to complete the first...

Homework Statement http://rsteiger.is-a-geek.com:81/homework%20question.jpg The question for me is merely conceptual. I'm really good at math (not that a lot would be required here) but I don't even know where to start, hence the lack of an attempt. I'm not looking for the answer (I already...

Homework Statement a) The number of molecules hitting unit area of a surface per second is: 0.5vnf(v)dvsin(s)cos(s)ds Show that the average value of cos(s) for these molecules is 2/3 b) Using results above, show that for gas obeying Maxwellian distribution, the average energy of all th...

I'm taking a first course in PDEs this term (I'm a physics student) and we are using "Beginning Partial Differential Equations" by Peter V. O'Neil, which I find almost unreadable. Can anyone recommend a good book appropriate for an introductory PDE course? I have taken a standard ODE and...

I need a little help with this assignment from my neuroscience class. I have tried to answer them but I'll like to know if my reasoning is right or wrong. I had to use the Neurons in Action software at school for some simulations but I think most of the questions could be answered without it...

Homework Statement A race car with the weight of 10 000 kg is traveling at 10.0 m/s when it's gas runs out. How far will this race car travel till it reaches an absolute halt? Homework Equations F=ma v2^2-v1^2=2ad The Attempt at a Solution Fn= 490 000N v2^2-v1^2/2d= a and I...

1a. Find the number of vibrational, rotational, and translational degrees of freedom of CH4 and CO2. 1b. Use the equipartition theorem to calculate the molar specific heat for hydrogen (in gas state). --- Attempt at solution: 1a. # traslational degrees of freedom (d.o.f.) is 3 for...

Homework Statement A model rocket is launched straight upward with an initial speed of 46.7 m/s. It accelerates with a constant upward acceleration of 2.16 m/s2 until its engines stop at an altitude of 138 m. What is the maximum height reached by the rocket? How long after lift off does...

Homework Statement If 57.5% of the fission neutrons escape from a bare sphere of 235 Uranium, what is the multiplication factor of the sphere?. In this system, the average value of nu being 2.31. Homework Equations nu= number of neutrons emitted per absorption in the fuel The Attempt...

Can anybody recommend a good introduction to QFT book? I'm looking for something that just barely classifies as a textbook, with lots of tutorial verbiage between the equations. Thanks in advance.