Hi Definition and 264 Threads

Wooohooo, up all night writing a history essay on Galileo's impact on European history. :cool:. Anything interesting happen on PF lately? :-p

Hi, I have two question about transformer and regulator: 1- When one refers to “isolation” with respect to a transformer, what does it mean? It related to the fact that the transformer blocks DC component of the signal? 2- this question is related to the electronic regulator 7812...

ok this is my problem... i have diagonalized the A matrix with the equation P^-1*A*P and the result is J=[-1 0 0;0 2 1; 0 0 2]. in order to find the e^Jt do i need to do the following? => [-e^t t*e^t 1/2*t^2 *e^t 0 2*e^t t*e^t 0 0 2*e^t]...

Homework Statement A dirt bike rider needs to complete a course that includes a "triple", a jump over three small hills that are speerated by a distance of 50 meters. The incline for the takeoff point is 37 degrees. How fast must the dirt bike rider travel to land 2.5 meters on the down side...

At 350degress celsius the equilibrium constant is 70. at equlilibrium the concentration if HI is 1.32 mol/L and that of H2 is 0.100 mol/L. what is the concentration of I2? would it be 0.32?

I'm getting back into Astronomy after a short period (ok 17yrs ;) ) I've brought my self a very cheap telescope £23, its not the greatest but its some to get me started, but I am now in the process of looking at buying another one I have up to £250 to spend on a new one. Can anyone recommend a...

Don't think me silly, but the first question is, where do excess neutrons go? If I do a fission reaction and get protons they are just ionized hydrogen atoms, a free electron is just a negative charge to find a free proton somewhere. But since a neutron can't get back in a nucleus, where does...

He's an Irish Microbiologist living in the Netherlands. He is the funniest person I've ever met and I finally convinced him to join the forum. It would be nice if he stayed in one country for more than a week so I could figure out where in the world he is.

hi all and good day... i'm luzirahs, 28y/o guy from Kuala Lumpur, Malaysia. i found out that this forum is so informative and the discussions are good. i feel like want to share my humble knowledge here and also learn from u guys. so, i registered here and here i'm. hope I'm accepted...

hi i m working on hyrogen as a fuel and need to now exactly how much energy is relesed during its formation.

hello, i was just wondering if there might be study guide or a good information source that could help learn about physics in preparation for next term. i can't quite seem to find any at the library or on the computer:(. thankyou,

hi there, i just forgot how to solve quadratics and was wondering if anyone could help me on a question it is quite easy. (x+3)(x-2)^2= 72 (x-2)^2 =x^2-4x+4 (x+3)(x^2-4x+4) x^3-4x^2+4x+3x^2-12x+12 =x^3-x^2-8x+12= 72 im not quite sure what i should do next if i haven't made any...

Hello there, Not too long ago, i have become very interested in physics, i think it was the end of year nine and I am just through half way of year 10. Our Physics unit is over now and i managed to get an (A) through an average of two quizzes(15% each) and a leveling assessment(70%). i got...

Hello there, Not too long ago, i have become very interested in physics, i think it was the end of year nine and I am just through half way of year 10. Our Physics unit is over now and i managed to get an (A) through an average of two quizzes(15% each) and a leveling assessment(70%). i got...

Hello all, new to the forum, so I hope this question isn't out of place or I'm contravening some rules, apologies if i am. Anyway, I got linked to this... http://www.webspawner.com/users/relativity/ Now, I had a SR course in the 1st year of uni, and I'm revising for a cosmology exam...

Homework Statement in a final burst of energy near the end of a bike race, Julia accelerates at 0.32 m/s^2 north for 15 s, attaining a final speed of 18.6 m/s south. what was Julia's initial velocity and how far did she travel while accelerating? The Attempt at a Solution In this case I think...

Hi all! I'm writer from Ukraine, writing book about Madonna's life. What do you know about Madonna? Please, tell me. Thanks! WBR, Svetlana Shmidt

Hi, can i know two phenomena related to quantum physics ?? hi all can i knw two phenomena related to quantum physics ??

Hi i really need help with dealing with logs: log x - log x = 2 3 9 so i change the base, since 9 is a power of 3. y = log_9(x) Then 9^y = x (3^2)^y = x 3^(2y) = x 2y = log_3(x) log_3(x) y = --------...

Homework Statement Given a connected graph G = (V,E). Let n = |V |. Each edge in G is already colored with either RED or BLUE. Devise an efficient (i.e. polynomial-time) algorithm which, given an integer k, 1 <= k <= n − 1, either (a) returns a spanning tree with k BLUE edges and n − 1 −...

Hi! Could anyone of you post here a link to a webpage that actually describes how a torque (of a screw) is transformed into a force that acts in the direction of the screw's axis, that makes is to screw in? Or could you briefly explain it? Any help would be highly appreciated.

Hi, my name is jimbodude and i like in UK:devil:

This semester I'll be doing a lab project using a radio telescope to map out 21cm neutral Hydrogen in the galaxy to make a nice big image of it. (First proper hands on experiment:smile: ). Anyway that's the basic idea of it but I'm hoping in it to try to find something more specific in it...

Homework Statement An airplane starting from airport A flies 247 km east, then 281 km at 29.3 west of north, and then 385 km north to arrive finally at airport B. The next day, another plane flies directly from A to B in a straight line. In what direction should the pilot travel in this...

Homework Statement What is the acceleration of your car? Time [s] Velocity[ms] 1 8.8 2 12.82 3 16.25 4 20.46 5 24.22 6 28.09 7 31.77 8 35.24 9 39.32 10 42.37 11 44.61 12 46.63 13 49.01 14 50.53 15 52.1 16 52.32 17 53.6 18 53.44 19 53.74 20 53.25...

Homework Statement k so we are doing a lab on determining the chemical formula of a hydrate (CuSO4.xH20) wat i need help on is these following questions: 1. suppose the hydrate was heated too quickly and some of it was lost as it spattered out of the container explain how this would affect...

Hello, I'm new here and I apologize for my first post being a design question. I'm a 20 year old junior Electrical Engineering student from the University of Akron. I need some help with a design that I can't get working for the life of me! If you know pSpice Schematics, or OrCAD Capture...

hi are you fine all i hope that today my son give me this problem to solve it but i can't can you solve Differential Equations are you can help me to solve it please:redface:

how I can slove this intergation ((e)^-x)\x) tank you

What is perpetual motion? Will it work in space?

What's the equation of a circumference that has center on (0,0) and a tangent line x + 3y = 10? The answer is supposed to be x^2 + y^2 = 10, but I don't know how to get there.

:rolleyes: Can anyone tell me the main attributes of: a loud speaker magnet? a compass needle? In terms of permeability, remanence etc. many thanks

hi to all...am a new member here...:smile: :!) hi to all...am a new member here...:smile: :!)

Hi all, pls help me solve the problem below,easy for you right? I very appreciate your help, thank. Question: A flash of light is sent out from a point x1 on the x-axis of an inertial frame S, and it is received at a point x2 = x1 + g. Consider another inertial frame, S´, moving with...

Hi everyone I am new to this forum and i hope that in this forum i'll learn and help others to learn and understand more about physics.

I know the answer. It is from homework. It is about tritium atom in its ground state which turns into He+. It says that right after the reaction, the wave function remains as that ot the tritium. The question is: what are tha allowed energies of the system right after the reaction...

Hi, new user here:cool:

So, if it is okay, would you mind answering this question? There has been much scientific study on the evolution of humans. Although all humans universialtlly want to be accepted, I've come to realize that this "god" that Christians are talking about is perfect. People want to be accepted, so...

Hi everyone, Im new to this forum, just saying hi and am curious about something. Although I done physics at school I haven't dabbled for a number of years now...Anyway, some friends and I were having a dicussion on various topics until physics popped up (2 of them are rather heavy into...

Hi everybody, I am having a lot of trouble in my thermodynamics course. Any help would be greatly appreciated. http://members.shaw.ca/KingofGods/Phys211Assignment2001.jpg . Thank you very much.

Hi do u know anything about fermi zones? I need some good articles to read about...

Hello all Never occurred to me until a friend made fun of me for not knowing how a TAP and a vacuum cleaner works. And even I was surprised! How can I not know!? Question 1. I know that turning on the tap means increasing the pressure so water flows out, and the more you turn, the more...

Hi, I'm not sure how to prove this http://img402.imageshack.us/img402/5367/buoyancyq0wn.jpg I tried developing a bit but I'm stuck, can anyone point me in the right direction please thanks

It is me wolram not kia, i am in the act of moving, a right pain in the ass, i have no internet, and i miss you all so much it hurts, i hope to be back online some time, but not sure when, but i will smite any anything that gets in my way :smile: to say i will be back, may send shudders down...

I'm studying at Physics ,but I am interested in materials engineering,and I want to learn more about M.M.E.in the world. :confused: thanks, maria

I hope you guys still remember me. I do miss you, and of course I miss PF as well. :shy: Also want to say hi to those who don't know me. :smile: Just a brief introduction of myself. I'm a rather old member here but have left here for about a year, and now I'm back! Why have I left? A long...

Hello all, I'm new to this site and think it's a great idea to have a Physics site to help with, b/c we all know physics is the devil... (j/k) :) Anyway I have this problem which I think i figured out but want to be sure. Suppose a block of mass 25 kg rests on a horizontal surface...

This paper http://arxiv.org/astro-ph/0505397 reports the discovery of a HI cloud near the center of the Virgo cluster. According to the morphology and kinematics of a plume in a nearby galaxy (NGC 4388), it is assumed that tidal forces or the pressure of the ICM gas have stripped this HI gas...

hi, does anyone know the character table for the inversion group?

Hi everybody, what do you think will Mr. Bush next move is he going to attack Iran? I have heard some rumors that U.S.A. troops are trying to find a pretext, (justifications), in order to attack Iran, as they did for Iraq, will they? I think they are just mad about the petrol nothing else...