Classical Physics

If we want to talk about the "origin of space" or the "emergence of space" as a first principle - before we introduce anything inside it ... what is it that we are actually referring to ? Sometimes the simplest questions are the hardest: "What do we mean by 'space' ?" Outer space ... sure that's easier to define: But what is "space" as we commonly refer to it, the "framework": in which we exist in which "things" exist in which we define and conduct experiments, observe the results and interrelationships, and deduce conclusions How do we define this "framework" from first principles: "Something" with: dimension volume or capacity (to store or …

If the air density of the Earth surface were 1/2 of the current air density, how much energy would be required to escape to the space by rocket? Gravity is the same as the current gravity. A) same energy B) more energy C) less energy D) others why?

I can vaguely remember a question i saw a few weeks ago, but it was multi choice and about identifying a hair follicle a circular aperture was used and dark fringe.<br style="font-family: Verdana, Tahoma, Calibri, Geneva; font-size: 13px; background-color: rgb(227, 227, 227); "><br style="font-family: Verdana, Tahoma, Calibri, Geneva; font-size: 13px; background-color: rgb(227, 227, 227); ">It went like: A hair follicle was found at the scene of a crime where they used a circular aperture at distance of 1m and angle 45(not sure if included). Whos hair was it;<br style="font-family: Verdana, Tahoma, Calibri, Geneva; font-size: 13px; background-color: rgb(227…

Can someone explain the angular wave number and the angular frequency?

from the day one i started doing science there is one unanswered question.... whether the light has mass? so anybody has a answer!!! is dat true light has mass in partical nature phenomena like compton effect,photo electric effect?

It is perfectly consistent to define mass as the frame dependent "relativistic mass" if you like. But it is a bit silly for 3 reasons: 1. All professional physicists mean "rest mass" when they say mass. 2. Rest mass is frame invariant, so a property of the particle, whereas relativistic mass is frame dependent, so dependent on the observer. 3. If m is used to denote relativistic mass, we have momentum p=mv. This is a waste of notation since p and v are now always proportional to one another. It is much more convenient to keep a non-linear relation between them, i.e. [math]p=\gamma m v[/math] with [math]\gamma = 1/\sqrt{1-v^2/c^2}.[/math]

meta pHYSICS,, "Why do we feel black when even our eyes are closed?"

How many directions might the relative headwind blow? welcome to my wormhole.007 bernoulli predicts lower pressure over top spin wind blows east/west-north/south Are there any other vectors the relative headwind might blow? peace ron hints look up, look down, look at my thumb which way does the eye of a cyclone levitate might aether flow through each and all and every singular one of us that my tongue marks you senseless tells more of you

I have seen how very useful the principle of least action is, but don't really understand why the integral of the Lagrangian with respect to time is minimized. It seems to say the most efficient way to get from A to B is via a "path" that brings kinetic energy closest to potential energy. (Yes?) If so, then why is that most efficient? Thanks for any insights.

WHAT CAUSES INERTIA? Does inertia effect time and if so how does it??

I have some questions regarding the gravitational constant and Newton's theory of gravity. To start, I am a first year physics undergrad student just so you have a sense of my caliber of understanding. Here is my question. As I understand Newton was able to come up with an equation for the gravitational force of attraction between any two massive bodies F= (M1*m2)/d^2 Later, Henry Cavendish invented an experiment in order to find the gravitational constant (6.673 * 10^-11 kg^-1*m^3*s^-2), originally intended to find the density of Earth, which happened a number of years after Newton's death. Cavendish's constant was about 1% off the number we use today. What I'm trying …

Hi All, To understand the Faradays law better, I have done the following experiment at home. I have taken a 12V battery, took a long wire and turned some 10 loops and shorted the wire to the positive and negative terminals. Now according to me the coil should work like an electromagnet and should attract small iron pieces. But I did not see anything happening like this. Could somebody please let me know how to conduct the experiment? Thanks in advance, Regards, Satya

Interesting forum topic shaping up here. A bit of a bore until it gets to the concept near the bottom of page three.... Link removed

Hi all, I'm having a small question about current flow direction indication in circuit diagrams. Its shown as current flow from +ve pole to -ve pole, but -ve pole has higher electron concentration (potential) & electrons flow from -ve to +ve. Whats the logic of showing the direction of current flowing in opposite way. Hope I have made myself clear. Waiting for reply. Thanks.

I did and experiment where I used a small circular cloud chamber to see the trail of mist created by an Alpha particle and I put a small cylindrical shaped rare earth magnet inside the chamber, the result was that every time an Alpha particle passed by the magnet the vapor trail left by it would be drawn toward the magnet and on some occasions the vapor molecules would find an orbit on the magnetic field of the magnet, I soon had a dozen or so molecules fallowing each other on a spiraling orbit from one end of the magnet to the other and then upon reaching the end just got flung off the orbit. my theory is that magnetic fields have a motion from the negative to the pos…

Hello everyone, lets say we have a object of mass 1 Kg kept on a table it will have energy at rest & potential energy. If I lift it to 1m up and kept it to same location back, object will have same energy. Can we say all energy is used in motion of object. Where that energy go? is it wasted/used? or converted to other form? Hope I have made myself clear.

Assume you have two identical cups, filled with identical water and identical amount of water. The only difference being that the water in the second cup is hot, the other room temperature. After placing them in a refridgerator, which one of the cups of water will freeze first, the room temperature cup or the hot cup? It seems logical to say that the cup with hot water has first to cool down (although it cools down quicker because of a higher temperature gradient as the room temperature water) to room temperature, and then it would take the same amount of time for it to freeze as the room temperature water, so it would last longer for it to freeze. Simple logi…

If you flip a scale upside down and hook it to the ceiling, then release a helium balloon under it, such that the balloon pushes up into the scale... A. What will the scale reading indicate? Will it really reflect the (negative?) weight of the balloon? Edit: Will it reflect the difference in weight between the balloon and an equal volume of air? B. Will the mechanics of how a scale operates prevent it from working in an upside down position? What if you "zero it" first? Edit: What if the moving parts of the scale were weightless?

Hello ladies and gentlemen! I could use some diverse minds to help me solve a problem with a potentially life saving piece of equipment. I am looking for a material that is lightweight, cost effective and has good anti-ballistic property's. I work in an environment where knifes and ice-pick are a greater threat then bullets. After a close call and armor failure, I am needing something better. I am playing with the idea of making a flexible roman reminiscent lamellar armor .I am currently working with Kevlar, HDPE specify delrin (polyethylene high-density) , Fiberglass (resin coated) ,vulcanized rubber, aluminum and PVC sheeting. My goal is to make round laminated d…

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What could you do when you want to get a physics paper,when you didn't subscribe the Journal? ( Several days ago, a professor of Europe asked for my paper "title and publication deleted" via E-mail, I send this paper to him. url and email deleted) no advertising of speculations subjects outside of speculations

When i ask this question many of you will envision the force of gravity, though this is not what i am asking. If everything with mass can exert gravitational force when confronted to another body with mass, is their a proportion for mass to gravitational field? example - for every G of mass their is an F to its gravitational field From what i understand this is heresy because gravity will always have an affect, no matter how far away it is from an object. I'm uneducated in physics having never taken a class although i will in the fall and have taught myself some basics. I'm really asking why this is impossible, not if theirs anything to it. How do …

Hi there, I wanted to check whether I got this one correct: Q: A bubble rises from a height [math]h[/math] from the bottom of a tall open tank of liquid that is at uniform temperature. Write an expression for the bubble's volume [math]V_{f}[/math] just before it bursts at the surface in terms of it's original volume [math]V_{i}[/math], and the uniform density of the liquid [math]\rho[/math]. A: By taking the temperature to be constant, the initial pressure to be that of the atmosphere plus the pressure at a height [math]h[/math] in the liquid and the final pressure to be simply that of the atmosphere. By using the [math]\frac{PV}{T} = constant[/math] equation I de…

If you're into science, which we assume you are if you are reading this, you should try the Gauss Rifle, named after the "The Prince of Mathematicians", Karl Friedrich Gauss. You'll need neodymium magnets, steel balls and two dowels to construct a rail for the balls and magnets to sit on before you "shoot" your rifle. It's a fascinating experiment that will make you wonder the various possibilities with this type of science.

Sand, being put through an hourglass or funnel, will fall through the hole relatively consistently. Liquid, however, will not. To test this, take an empty milk jug, fill it with water from your kitchen sink (you could also use milk, but kitchen sink water is expendable), and then, turn the jug upside down. It will fall into the sink in gulps, making a "BloopBloopBloopBloopBloopBloop" sound. Why does liquid do this? Why does it not pour consistently like sand does?