Basics Definition and 379 Threads

Homework Statement In control engg. we define the order of the system as (or atleast as far as I have understood as) Nu/s^m*(s+a)(s+b)... I cannot understand the base for such classification? Why are we classifying systems based on the number of poles they have on origin? Homework...

Suppose we have fluid in a vessel (Vessel A) with inside Pressure 120 bar (achieved by a pump)… When we open the valve, the fluid starts to flow into another vessel (vessel B) that was hitherto empty... Due to the Pressure gradient, the fluid flows with a certain velocity into vessel B. But the...

We're learning about the basics behind surface tension in chemistry and I'm having trouble applying what I learned. I've gone through my class notes over and over for the past 4 hours and I can't figure out how to even begin to solve the problem! Can I have some help understanding the basics...

For the second part of the tutorial, I'm suppose to compile and run to see what the output is. But, each time I click compile and run the command prompt shows up for less than a second and then goes away. What am I suppose to do?

Can someone either explain Quantum dots for me or point me in a good direction? I didn't have much luck with the wiki's I've seen. I would like an intuitive grasp of: what they are, how they are made, and their basic functions.

well if i understand relative motion quite well but while thinking about it i had this doubt- if A is in center of circle and if B is rotating in that circle, A would see B rotating rite? now , how would B see A?... there are more questions to follow up based on the answer...

Hello, Could you point out a good article(s) covering Perovskite crystal structures? There's plenty of literature out there covering perovskite structures, mostly properties or applications of individual crystals. Googling results are either very specific or too general or complete textbooks...

Homework Statement The Attempt at a Solution In rolling without slipping, the friction does some work of torque about the axis of rotation. So mechanical energy is not conserved. A) - r),t) B) and C) - r),t) D) - One example I can think for the instant centre of rotation is...

Q: Why is it that objects in orbit around other objects, tend to do that in elliptical patterns, and not circular patterns? I can picture objects of great mass, planets and stars warping the fabric of space time, and how moons and whatnot get caught spinning in the orbit. But can't wrap my head...

Okay... I've spent a week stumbling through this site, asking random questions, and generally annoying people. Here it is: What are the basic maths and physics laws someone should know before tackling quantum mechanics?

This is for a pre-lab. I'm given three points for force and acceleration: F(Newtons): 19.1, 24.5, 28.2 a(m/s^2): 127.2, 162.1, 185.9 Problem: I'm supposed to relate y = mx + b to the equation F = ma and I'm assuming then to use this to draw a line through the points. instructor has: net force...

I have been told that the relationship n.p = (n_i)^2 always holds, where n_i is the intrinsic carrier concentration. This makes sense to me for an un doped semiconductor (sc.). However, for a doped sc., I'm a tad confused. For an n-doped material say, the electron conc. is...

I started to go over Verlinde's paper (http://arxiv.org/abs/1001.0785) and I'm just not convinced of what he's doing from the start. At (3.5), he is assuming there is a particle within one compton wavelength of the holographic screen. Saying this immediately seems to imply that the momentum...

This is not necessarily a homework problem, as I am not in the course yet, but could someone please explain to me about the basics of friction

Hi everyone I'm trying to write a computer simulation of meshing gears (actually its for a videogame), but my understanding of gears and torque is sadly lacking and I'm having trouble finding the answers to what I think are probably very basic questions. I apologise if I've posted this in the...

What are the basic rules of quantum physics and how does it work?

Hi, everyone: This should be easy, but I am having trouble with it. I am rusty and trying to get back in the game: Let Q(a,b) be an intersection form in the middle homology class of some 2n-manifold. What is the geometric difference between Q(a,b) and Q(b,a).? If n is even...

I was doing tech support at a healthcare conference over the weekend in which one of the speakers talked about stats 101 and interpreting research. In discussing it further with my wife this morning, I realized we've missed a piece of the puzzle. My wife made an spurious example of cars...

From what i understand quantum mechanics has large part to do with probabilities. So is it valid to say that if i walked head on into the wall in my room for an infinite period of time that eventually i could be able to walk straight through it? Also is there a way to calculate a simpler version...

Basics on Quantum Physics... I have Two basic Questions which I need an easy, simple answer... First is...What is Spin of a particle? any simple way to define it?

In The Road to Reality, § 15.2, Roger Penrose introduces the concept of a fibre bundle. Here I'll modify his notation to that of Wikipedia and other sources, so that B stands for base space (rather than the bundle), F for fibre, and E for the total space, which I think Penrose calls the (fibre)...

Hello, I was reading Zeh's "The Physical Basis of the Direction of Time" but I just can't understand him in chapter 1 on something really easy: the definition of the phenomenological entropy + second law. Here is a screenshot I took from the googlebooks edition: Those two lines of...

What I have heard *about* the principle of equivalence is a great and grave over generalization; primarily that gravity is equivalent to acceleration. I would be prepared to acknowledge that it is highly likely that the behavior of free-falling bodies in the region where F=m*g would be...

Hello, am trying to make pcb at my home, but am not sure about the sequence of fabrication steps. i put the board in UV light for several minutes, then i put it in a basic solution and finally in ana acidic one, but nothing happened to my board... What are the names of bases and acids used for...

Why is the vertical axis time multiplied by the speed of ligth? And, what is the purpose of using Minkowski space?

Hi, I am having this problem learning interacting fields. In scalar Yukawa theory, two scalar fields (one real call meson phi, one complex call nucleon psi) (interaction term psi-dagger*psi*phi) why can't we write at first order in the interaction an amplitude from a single meson state to vac...

Hi! I just need some basic things cleared and I would really appreciate if someone helped me out. Here are a few questions that put forward my doubts: 1. Thermodynamic equilibrium requires mechanical equilibrium--please explain. 2.How many state variables (Voume,pressure,temperature...

http://www.exoplanet.eu/catalog-all.php?&mode=0&more=yes". On one of the this it has for the for each exoplanet, in the list it gives the information about the parent star's properties especially its phototemetry. Specifically it lists star's the V-order, I-order, H-order, J-order, and K-order...

hi everyone! I'm sorry if this seems like a really easy question, but... Suppose I have a device in which manually rotating gear A clockwise causes gear B to rotate clockwise. If gear A and gear B are at a weird angle to each other (say 35 degrees), what sort of intermediate parts could I use...

Hello gang. [I used the search but couldn't find much except for recommendations for Horowitz's Art of Electronics, so I apologize in advance if I missed a similar thread somewhere] I realized that my knowledge of electronics, circuits, and the like is appallingly bad for someone who claims...

Two baseballs undergo a head-on collision. Ball 1 is twice as heavy as ball 2. Ball 1 is traveling at an initial speed of v1, while ball 2 had an initial speed of v2. Elastic collision. If ball 1 travels at a speed of 7/5v1 after impact, what is the speed of ball 2? Conservation of...

Hello everyone, I just started reading "Fundamentals of Statistical Signal processing" by Steven Kay and just got done with the first chapter, which describes the estimation problem, PDFs etc. It has some very interesting problems at the end and some of them have me a bit confused. I think...

So we are learning the basics of integration now.. i don't quite understand how it works.. a little help please?

Can anyone help me get started on the basics in electrical engineering or maybe sending me some of the threads that already exist in the forum that are related to the basics and introduction of EE. Would be glad if someone helped, thnx!

Learn "advanced basics" of statistics? I'm a physicist and would like to prepare for a job interview where the job is to do statistical analysis and optimization of models for medical data or so. The firm does consulting for pharmaceutical companies. Anyway, I know the very basics of...

Basics Physics...Need Help Homework Statement -In a movie, a stunt man runs horizontally off a cliff at a speed of 6.0 m/s. The stunt man lands in a deep river that is 23m below the cliff. A) Determine when the stunt man lands in the river. B) Determine the horizontal component of...

Homework Statement The acceleration of a particle is defined by a = -8 m/sec2. Knowing that x = 20 when t = 4 and x = 4 when v = 16, determine: The time when the velocity is zero The velocity and the total distance traveled when t = 11 Homework Equations The Attempt at a...

Hey all, I've just started grade 11 and started studying Physics for the first time, so I have very little knowledge in Physics and find it very difficult to understand things that are given to me during class and reading them off the internet. Some of my main questions that I have trouble...

Hi there. I have just started to read about the Relativity part of Maxwell's equations and would like to get some clarification from anyone here were I can discuss and/or get answers in a more " every day life " way of writing. 1) What is the most simple way of transforming Maxwells...

could anyone help me with cnc turning process, diagram of machine. it be better if you can give me manual book about it. i need to learn about cnc from introduction and part of that machine. I'm new in this course.

I'm trying to understand the meaning of the components of the stress(-energy) tensor. Considering just the space-space components, is this right? T^{ij} = \frac{\mathrm{d} F^i}{\mathrm{d} A^j}, where F^i is the x^i[/tex]-component of force, i \neq 0, and \mathrm{d} A^j is an area element...

I am in general chemistry I, and need a little clarification of the following: When balancing an EQ say CaSO4 + AlCl3 \rightarrow CaCl2 + Al2(SO4)2 The subscript 2 outside of the parentheses confuses me. Do I distribute that 2 to make it S2 & O8? This is a homework problem, but I do not...

help me about karnaugh maps

Say I make a simple crystal radio using a 1N34A diode. If I use it to tune in a radio station 100 miles away, would it be possible in theory to detect an infinitesimal increased load at the station when I tune it in with my crystal set?

As I https://www.physicsforums.com/showthread.php?t=283482", I'm struggling with physical basics of vibration in rods as a non-physicist. If someone would be kind enough to explain in simplest possible terms, I would like to understand two things: 1. What is the relation between standing...

Hello, First of all, I'm not sure if this is in the right section, and I know it's probably a very basic question compared to all you levels of knowledge. So please if it isn't in the right section, let me know where I should post it, and if not thanks in advance for the help. I'm trying...

Does a given lattice of a torus (either twisted or untwisted) admit only certain orbifolds - ie. only specific N of Z_N ? For example, consider the twisted torus lattice (in complex plane) in page 121 of Green, Schwarz & Witten 's Vol-2 book. It is said (in page 122) that the torus is special...

Hi all, I am sorry if I have posted this thread in the wrong region. I am in 12th standard presently. I wish to pursue mechanical engineering in college.. mainly mechanical + electronics.. All i want to ask is where should i begin with? Which books(or any other source) should i refer to...

I'm reviewing my Group theory notes at the moment. I have a few questions. 1)what is the "connected component of the identity"? (How would you go about working this out?) 2)Why is Lie(SO(n))=Lie(O(n))? 3)Why is the SU(2) Lie group isomorphic to a sphere in 3D?

Is there anyone can describle phase ac?