Classical Physics

So I was reading the derivation of the wave equation in Halliday's physics, and I saw that they made the simplification that the wave had a very small amplitude, in essence they assumed that the amplitude of the wave is very small and so an infintesimal segment of length on the string (dL) could be said to be equal to an infinetessimal segment of the x axis (dx). Now I decided that I didn't like this assumption and seeing as I ca't sleep at the moment I decided to re-derive the formula without the assumption that the amplitude is small. I also don't have a physics professor who could really comment on anything thats not clearly written in the book with any sense of …

I'll be honest, this is a practice Homework problem. (It's not graded). I just need help getting started..Any help is appreciated. Thanks! An archer shoots an arrow over level ground. The arrow leaves the bow at a height of 1.5 m with an initial velocity of 60 m/s in a horizontal direction. a. How long does this arrow take to fall to ground? b. At what horizontal distance does this arrow strike the ground?

I must have missed something about the standard definition of moment of inertia. how did they come up with the basic formula I= the integral of radius^2times dm? Cheers

Is their a formula to predict which type of decay a radioisotope will go true, what I mean is can one predict if a given isotope will go thru beta alpha or gamma decay?

Say you have a fitted but freely moving piston falling in a large cylinder. The piston weighs 100kg but only weighs 1 kg under water. The cylinder is filled with water, but there is plumbing going from the bottom of the cylinder to the top. The plumbing is also filled with water. As the piston moves down in the cylinder the water is free to move from beneath it, through the plumbing, and back to the top of the cylinder in a continuous loop.Lets assume the plumbing is of the appropriate shape and design to allow the water to travel as freely as possible. What would the velocity of the piston be after a 20m freefall?

Yestarday I was reading an article published in the local daily. It was saying that Animals like Cows, Dogs, Pigs and Horses survived from tsunamis and earthquakes. Do they have sixth sense?

I know that a hole through the earth wouldn't work because it constitutes perpetual motion. But what exactly would stop you from falling, reaching terminal velocity, falling the other direction, reaching terminal velocity again and oscilating like that forever? It couldn't be friction, air doesn't stop you from reaching terminal velocity if you jump out of a plane. Does terminal velocity not bring you far enough into the other side of the earth to reach it again? Long post, I know.

Take a look at this site. There was a big controversy on slashdot over whether that was truly an antigravity device. Another site I found is americanantigravity

Guys, you have GOT to help me out here. Today, I went with my grandparents and my little cousin to Santa Cruz, California, where we passed through (and entered) the "Mystery Point" - a place where they claimed the laws of physics are different. Obviously, I was sure everything is an optical illusion, but it sounded like a nice detour and a great experience, so we stopped by and got in. I am still slightly confused. There is no doubt that optical illusions were part of what we experiences, but it is DEFINATELY wasn't all it was. The forces active in that point were clearly felt and visible, and I have GOT to figure out what the heck it is that happened there. I n…

First of all, everyone who took high school physics knows that acceleration can be modeled by the slope of a line gragh, where the x-axis designates time(s), and also where the y-axis designates velocity(m/s). But I have a little paradox that kinda bugs me. Let's say that an object is moving at a constant speed of 5m/s, and then for some reason, (the reason is irrelevant) it just stops without slowing down. Now I plotted it on a graph, and apparently, the acceleration of the object is infinite. Am I missing something here?

Does this device really work ?, (wouldn't the copper pipe shield the water from the electric field ?). If it does work, how does it work ? http://www.scalewizard.co.uk/howitworks.htm Here is a similar device:- http://www.scalewatcher.co.uk/pages/whyScalewatcher.asp "Scalewatcher" claims to use "audio frequency" signals.

Hello, to put simply. i have an engine and a small sized turbo that allows 9psi of air into the engine. an where the pressure is read from is a 2 inch pipe(lets say) that thereafter goes straight into the piston. ok so the system is EXACTLY the same.. but we change the size of the turbo to a bigger one.. an still have it at 9psi..... my friend reckons that the car goes faster with the bigger turbo... but i dont see how that is possible.... can someone please rectify this problem thank yohu.

I have just started working as a supply high school teacher in science. The lab part of the courses doesn't seem to interest the students all that much and I don't really blame them. The experiments are very basic and not that impressive. I am trying to think of new experiments and I was just wondering if anybody had suggestions about sources to consult (internet, books...). The courses that I teach touch a broad range of subjects: mechanics, optics, electromagnetism, thermodynamics, general chemistry, technology, earth sciences, biology... Thanks for any suggestions

IF I invert a test tube, with it fully filled in with water, and put it above a beaker of water, just like the process of electrolysis. What is the pressure at the bottom and at the mouth of the test tube? I guess the pressure at the mouth is 1 atm, but where supports this relatively large value apart from the little weight of the water held?

Hello, I want to determine the kinetic impact by meter square. The data I have is: speed, weight, diameter and lenght of the object.

Hey all, does anyone know where I can get decent information on the physics of catapults? thanks.

I noticed that steam condensing on the underside of a horizontal surface formed drops which only dripped off when they reach a diameter of approximately 15mm. Is it possible to calculate the interatomic forces between water molecules from this observation ?, (given: Avogadro's number, the molar weight of water, coordination number of liquid water, and acceleration due to gravity).

I've been trying to solve this problem for a while. Suppose two blocks with mass 1kg each are stacked on a frictionless table. Suppose the coefficients of friction between the blocks are 0.6(static) and 0.5(kinetic). If I push the upper block with a 7N horizontal force, what should be the final acceleration of each block?

Consider there is a car driving in a horizontal circular path, as stated in my book, a radial force exists and causes the car to accelerate towards the centre. Here the questions are: why the acceleration must be towards the centre? with a positive acceleration in a direction perpendicular to the motion of the car, the car should be accelerate towards the centre and this results in an increase in the speed of the car but the fact indicates that is impossible, why? Besides, what is centrigual force? Is it prerequisite in order to have a complete understanding of rotation? This question I've tried the web links in my books, and other E-books, however, I still …

I remember reading about the three body problem from the advance notice article I received for my OCR synoptic physics exam. In fact, I have it here with me now. To get to the point, it interested me very much and made me wonder if it could have been solved, and worry; rather stupidly that it might be on the exam. Anyway, I'm glad it wasn't, as the article stated there is no comlete solution to the problem. Why is this? Are the solutions to this problem only approximate? If so, are methods involving matrices involved? Also the french mathematician Jospeph Louis Lagrange is credited with finding special places where the smallest body of a system(consisting of an as…

Here's a curious experiment see if you can guess what will happen and more importantly figure out why it does what it does, to date no one seems to have given a clear answer, no one seems to know how this works including myself. take a bar magnet and tie a string in the middle, then suspend it and twist up the string or rubber band whichever you like so that when released the magnet will spin such that the poles are rotating parrellel to the horizon( you can put a small electric motor to the end of the string also which is what I did eventually it works better). Now that your magnet is spinning take another magnet in hand and hold either pole next to the spinning mag…

Hey, I've got a question I've been thinking about. I'm going on a rafting trip next month. There's a rope swing next to the river. If I want to swing on it, let go and get the most distance at what point in the arc of the swing do I let go? I realize that my speed is greatest at the bottom...and to release when traveling at 45 degrees with reference to the water (normally the best trajectory) I will almost be stopping at that point in the arc. Please help so I can impress people with my distance, hehe

Does anyone know any references about fluid dynamics as a field theory? In particluar I wanted to know more about the symmetries of fluid dynamics and possible Lagrangians. The only references I know are HEPPH-0407101 and papers by the same people. Are there any others out there that I don't know? Cheers

Can anyone suggest me a good book on mechanics that starts from senior secondary level and takes you very far(may be Msc. level or at least Bsc.) Also,it will be good if It will have some sort of revision chapters on the required maths. Thanks kenshin

I am trying to figure out something that kinda puzzles me about how an airfoil works. From what I know, air moves over the top faster than under the wing, creating a lower pressure region of air over the wing, creating a vacuum style lift effect. That all makes sense, but what I don't understand is, is how you can get so much lift from that simple process. The difference in air particles above vs below cannot equal the mass of a boeing 747, so how does it generate that much lift? Am I just looking at it wrong? Should I be comparing the pounds per square inch of air pressure that push up below the wing, to the far more neglible pounds per square inch of very …