What is Basics: Definition and 378 Discussions

We have been going over causal systems and I am still having trouble determining what defines a system to be causal. I was told that if the input is anything besides x(a*t) where a=1 then the system is non causal. I can kind of see this, but it is still a bit blurry for me. I also was...

hi please can anyone tel me how to control a motor connectd to an electronic chip connected to the computer uning serial port , using visual basics(iknow how to use VB )

I'm having trouble learning electronics because I don't know what to start with. For example in order to learn about capacitors I need to know what they're used for. I know they store charge but I don't know what this stored charge is used for. When I read up on them it tells me they're used for...

Can anyone suggest a textbook/paper or two that serves as a good intro/reference to reps of SU(5), SU(5) GUTs and embedding the SM? I am looking for something that is beginner-ish to medium technicality. A reference of some sort that summaries all basic results and properties. thanks in...

Homework Statement Trying to prove some of the basic laws in set theory, and would like any opinions on 1 of my proofs (eg hints on how can I improve it, is it even a valid proof). Thanks in advance. (A \subseteq B \wedge B \subseteq C) \rightarrow (A \subseteq C) Homework Equations...

hey i know the basics about complex numbers like: 5*i^7 = 5*i^3 = 5 * -i = -5i = (- pi/2, 5) but now : how would i represent : -> 1 ^ i = ? = ( ? , ? ) or would it involve another mathematical dimention and be more of a (? , ? , ?) ? //////////////////// and now, how can i...

Homework Statement I have two vectors V1 and V2. V1 is parallel to xz plane V2 is perpendicular to V1 V2 is 10 units.Can i get V1? Homework Equations The Attempt at a Solution Force triangle?Can''t solve?

Hello. My understanding of this subject is limited. I thought I basicly understood it, but now it seems my concept of it was similar to the theory of the http://en.wikipedia.org/wiki/Luminiferous_ether" . I've read more about it but I still don't understand, and wondered if I could ask some...

<b>I need a brain refresher</b> to see if i have everything straight in quintic and quadratic expressions. The n's in an expression represents how many turns a line would have The amount of (x+1)^2 means a quadratic curve The if the n is odd there are no complex roots Now here is the...

I'm trying to get a grasp of the basics of a Tolman SB test. Please correct me if I'm wrong: To be able to do a Tolman SB test you first have to observe a couple of identical objects at different redshifts. "Identical" here means objects of the same spectral type and luminosity class. Then...

Hello All! I'm very interested in learning about particle physics and am wondering which book you guys recommend as a starting point. I'm looking for something in between undergrad and grad. So far it seems like the two best choices are Griffiths' Introduction to Elementary Paticles, and...

I have a fundamental question regarding conservation of momentum (not homework). So if we have a system of 2 balls, identical in size and weight, one of which is initially stationary until hit by the other ball. We have the following: m1v1 + 0 = 0 + m2v2 or v2 = v1 and therefore...

Could anybody please explain the concept of extended plane and extended space? I know the definition of an ideal point and that's the only part that I really understand. If each two distinct planes (in extended space) meet in just one line, does it mean that there's only one ideal line for each...

I had to withdraw from this semester due to medical reasons and I would rather not repeat the two engineering classes I took - I feel that I can study what I missed and master it. My only option is to take a test my school would give me in those two classes that I couldn't complete and if I pass...

hey, i'm just trying to learn about special and general relativity and i figure a good place to start is with minkowski space since that is the basis of special relativity. I have a few questions though, i hope you forgive me because these questions will sound rather ignorant and silly i...

The Health Physics Society is an excellent resource for information on radiation and radiation interactions. http://www.hps.org/publicinformation/ate/cat47.html The following FAQs have been developed by our topic editors for this category: How Can You Work Safely Around Radiation...

Hey i was wondering if someone can help me out with radios and whatnot...i know making transmitters are illegal but i was just curious as to how they work as well as receivers. The thing that confuses me is how do you get information to and from the signal? I mean if i made a tank circuit that...

I've just started multi dimensional calculus, among which Langrange's Multipliers. I have some questions which will help me grasp the concepts since I'm a very curious guy... a) What are you finding exactly with this technique? b) What is the constraint? c) What does the extra variable...

I've just started multi dimensional calculus, among which Langrange's Multipliers. I have some questions which will help me grasp the concepts since I'm a very curious guy... a) What are you finding exactly with this technique? b) What is the constraint? c) What does the extra variable...

The acceleration of a particle on a horizontal xy plane is given by a=3ti + 4tj, where a is in meters per second-squared and t is in sec. At t=0, the particle has the position vector r=(20.0m)i + (40.0m)j and the velocity vector v=(5.00m/s)i +(2.00m/s)j. At t=4.00 s, what are its position...

Hello everyone, Could someone explain the basics of the qubit particularly pertaining to quantum computing? Maybe if you know any good links that explain the basics or if you could explain it yourselves. I appreciate it a bunch! Thanks guys!

I know I am thick! I know this sound stupid but my kid has brought his homework home and although I am OK at higher maths i seem to have lost the ability to do the basics! :eek: Can anyone help with this... A car leaves a quay and ends in the water 6m away from the foot of the quay. The...

I know its a banal question but I am new to calculus course and there are no math teachers in summer... also my book does not explain it Why it is \mid a_n - L \mid < \varepsilon And not just L - a_n < \varepsilon ?? wouldn't the relation be the same?

Hello, guys. Last week I have begin my study of linear algebra from cero. I am learining about the basics of matrices. Please, I would like to know if this is ok: 1. Let "In" be the identity matrix (n x n). 2. Let "e1" be an elementary row operation such that, applied to In, we obtain...

I went through primary and secondary school without (any?) knowledge of the theory behind English. Although I am capable of writing an A level essay. But I like to start learning the basics now. Could anyone recommend good books with lots of excercises on the basics of English?

I am new to nuclear. you could answer me one question : why do people say "fission", I thank you

Alright, I've learned a lot of electrical physics over the past month. So far, I know about charges, forces, fields, flux, potential, and capacitance. The problem is that I'm having a hard time visualizing how these properties relate to each other. I'm also having a lot of trouble knowing which...

Hi, I'm building a rocket, and my team is planning to use airbags to protect the tanks from crushing during landing. I'm a newbie at this, and I want to know where I should start:) Thanks

Can anyone here help me to derive that during an adiabatic expansion, PV^gamma?is a constant, as well as other expressions similar to the above? I have found the following equation using definite integration and the basic formulae, nRdT/gamma - 1 = work done.

Hi, I'm wondering if mechanical engineering requires a fairly extensive knowledge of the basics of electrical engineering eg. circuit theory and the practical side of it.

First off i want to say thank god i found a board dedicated to helping out with physics, i am having so much trouble with this subject, and ironically, I am pretty good in math. well anyways i wasnt to sure about posting here or in the homework/class section, but since i just need to know the...

I know very little about General Relativity, I don't know what a tensor is and don't know any of the mathematics involved (even though I know pretty much all of the equations in Special Relativity.) Could someone please explain tensors to me, or point me to a link that does? And where can...

I know it's embarrassing to ask this. But I don't know anything about the stuff about Internet, server,... What's a static IP? How can I create a static IP? What's a port? What's a port used for? How can I establish a port? What's DHCP? What does it do? And what's MAC? I tried to search for...

I've posted this in the homework section since it is an assinment. I am required to write a program in VB than creats N number of 'particles' in a random position within a caresian co-ordinate system. The x and y-axis are to go from -100 to 100 and be bounded i.e if a particle's x or y...

(100) (.2)x(.8) 100-x x Trying to solve this using 1, then 2 for x. The same parentheses are around both the 100 and the x. Thanks

Could some one help me where to get free tutorials to learn physics. From basic to depth.

I've just found a review of m-theory which should be very interested for you. http://arxiv.org/abs/hep-th/0509137 "This is a review article of eleven dimensional supergravity in which we present all necessary calculations, namely the Noether procedure, the equations of motion (without...

Hi.i have a question about Field of view. I know that it is an angle showing on a triangle.inside the area of the triangle any object can be photographed .am i right?i know tha it is not a scientific explanation, i am just saying what i have understood. i have a camera. I do not know the...

what is general relativity really talk about?

I was just wondering, can you name of the books, which they are kind of basic, and explains all the formula's. Just name the books that's all.

hi, Can someone suggest some good books in Control Systems engg. which includes all from laplace to bode plots,nyquist etc etc. Thanx for any help.

I've got a basic idea of string theory but if anyone can give me a sort of overview i'd be grateful thanx :cool:

can anyone tell me how AM transmitter works?thanks

Hi all any ideas wat computational fluids dynamics is all about.. how should i go about using it, using codes? Wat kind of codes are used? Is it C programming or stuff like that? Thanks regards ss

Here are a few questions about quantum mechanics (Bohr’s atomic model). 1. An electron is a particle revolving around the nucleus. So it should radiate energy (by classical mechanics). But if this energy comes from the orbital, it must finally become 0 and the electron must crash into the...

I am having trouble making sense of the KE=1/2MV^2 formula. If I am interpreting it correctly, it is stating that twice the speed = 4 times the energy. To my way of thinking, it seems to violate conservation of energy and relativity. I even did a simple experiment ( dropped a weight on...

For a computer beginer, what should i recommend him to start learning from? Thx

I have no idea how AC Motors work. Can anyone point me in the way of a basic book or website which explains how they operate :confused: I need to know about them for my new job :blushing:

Could anyone explain how red tacton works in terms that a high school junior would understand? ^_^ thanks.

Please Help Explain... Can sombody please explain what all the unification theory has to explain to be right. As far as pass theories (that have to be still be correct according to it), and what forces goes. :tongue: