Physics

hi was wondering how the phonon begins - as in association with the electron-phonon interaction, as the lattice is at very low vibration (to begin with)? and also how exactly the cooper-pair stays in one piece ? how is it so... thanks

Hi We all know that Force = Mass * Acceleration The problem to me is that what should be the acceleration when a object is pushed by hand feed ? Thanks Zirok

Pretty much just what the title suggests: What would happen if two black holes collided and one of them was anti-matter?

Hello everyone, I have got confused with this. Normal the friction force acts to cancel the force. If I travel with 10 N force and friction is 5N, I travel at 5N. Why is that when you make a turn they don't create a net force, but act as separate forces? EDIT: I suppose the tires are turning outward all the time in different directions to keep it on the road. when you have turn in the circle outward force is little bit greater than friction I think, which makes the car turn in the right direction, before it is stopped by friction again.

Hello everyone, When you go down a lift, are you actually falling down. Is the lift carrying you down, or are you falling down due to gravity towards the lift, if the lift goes too fast would your head crash? Sorry if my thinking is completely wrong. Ok now apparent weight is from the normal reaction force. Muscles pump blood up via veins and then they fall due to gravity and other factors. So when they fall and hit the interior of the foot, can't you feel it. So isn't apparent not just the normal reaction force. Thank you

Hi, guys! I really need help! Does anyone know any cool experiment that involves light refraction and optical illusions? Something simple! Or maybe just something cool with light refraction... Perhaps there's a page with physics projects related to this that you can suggest.. Thanks!

alright so if I apply a voltage to a loop of wire in a constant magnetic field, then it should feel both a torque and after some period of time it will have a (presumed) constant angular velocity. my question is what that final angular velocity is going to be and or, the function of time that gives us the angular velocity at that time. also, what would the torque on the motor be as a function of time? I've been working on this problem on and off for the past couple days after seeing a simple electric motor demonstration, I ended up with 4 equations that I thought I could use, namely an equation for the torque on the loop as a function of I,angular velocity, and t…

If you come in contact with any object, it is not going to resist your movement right, why doesn't ice do this much. What chemical property is responsible for this?When I slide in ice, am I coming into less contact with ice, I don't understand. Thanks

Hello! Few years ago, I tried to think on methods to transport freight and humans to space economically and safely. I thought at that time, moon elevator could be created if powerful cable can be produced from development of carbon nano-tube technology. Through moon elevator, space development of mankind, commercial travel to space and moon will become possible, and contribute enormously to development of human civilization. Please have a look at the following introduction of basic concepts, and compare relatively with "space elevator" and its feasibility etc [Moon Elevator] 【Brief explanation on Figures】 Figure 1 is structure diagram of moon elevat…

Someone once told me that an electron can move from one body to another. And those two bodies can be constantly exchanging electrons. I don't think the name for this phenomenon is "electric slide." Does anyone know the name of this phenomenon? In general, the person said that from my body (human body with clothes, etc..) to that other person's body, electrons move back and forth between us.

Hello everyone, Let's say there is a tripod. I attach a string to the tripod and then attach a mass to the string. The string with the mass ,stretches a bit and then the mass hangs in the air. So this means the weight force of the mass must be balanced by the tension of the string. Now let's say this tension is coming from the elasticity of the string. Now after the mass is hung, I take it off and look at the string, now it is stretched and loss its elasticty. So if I attach this string to the tripod again, and hang the mass, and it stretches a bit and stays stationary, where is the tension of the string coming from. It can't come from the string because it has lost i…

Does anyone get how to find the magnification of a specimen just by having lattice spacing as a clue? I don't know any formulas so I don't know how to solve it.

I searched the internet for the last 2 hours learning and understanding the Watt/Watt Hour/BTU conversions using data collected. I am not sure what I might be missing, but Wikipedia has supported that a defined Watt ~ 3.412 BTUs. Some simple constants: 1 Watt (W) = 1 Joule per second 1 BTU Hour (BTU/h) ~ 1055.05585 J 1 hour (h) = 3600 seconds (s) So, inherently, a simple formula can be derived to convert BTUs into what I believe should be Watts: W = Joules(BTUs)/Time Elapsed(seconds) OR 1055.05585/3600 ~ .293 W Rating Their number of 3.412 has apparently been used by applying: W = 1 Hour (Seconds)/Joules OR 3600/1055.05585 ~ 3.412 W Thi…

Now when the spring recoils, it loses its elastic potential energy to the dart. If it loses its energy how does it come back to its original shape. I'm thinking it is the elastic potential energy that is used to make the coil come back to its orginal shape. Also let's say a spring was compressed and I took my hand away. Now it recoiled back to its shape. The spring didn't transfer any of its added elastic potential energy, to any other object. So does the spring has more energy now. When I compress a spring I'm thinking I'm adding extra potential energy. Am I adding extra energy or, changing the allready existing energy in the spring to elastic potential energy. …

This might be moved to speculation: Like we still don't know the extent of the universe, can there be something like a smallest particle? Everything has to be made of something smaller, right? Is it that the smallest particle defined will be the maximum one can magnify things in that period of time? Is it sort of a continuum that everything has to be made of smaller particles?

Hi, was wondering why plastic is not conductive.

According to the following paper, the displacement current doesn't produce magnetic field. Is the Maxwell's theory wrong? Poincare pointed out that the displacement current violate momentum conservation. How about the energy? Why do we still use Maxwell's equations? References: The present status of Maxwell's displacement current John Roche 1998 Eur. J. Phys. 19 155

Hello everyone, If an object is hanging from a string in the wall. It is stationary so this means tension of the string and weight force of the object must be equal. Is this tension coming from the elasticity of the string. So if the string loses its elasticty by a heavy force, does that mean there would no be a tension foce and the object would keep going down and fall to the ground. When the spring is elastic it stores its energy as elastic potential energy, when it becomes plastic like, is this energy converted to change the structure of the object.

Hi, was wondering, is it that something (metal) can only be conductive if the electrons can be delocalised or are delocalised (already)

If I push a spring on a stationary wall and release, the spring would fly in the opposite direction right? I understand that there is elastic potential energy stored and this causes the movement but when I normally compress a spring it springs back to its orginal shape, how does it fly away in other direction. For example when I compress a spring against a wall, why doesn't it regain its original shape and fall down, why does it fly away instead. I'm thinking the elastic potential energy is used to make the spring go back to its orginal shape. Thanks I'm trying to understand newton's third law using this. If I push a book, it will push back on me. How does this occur…

Hello everyone, May be the question is when something has energy and there is no resistance why does it move? Thanks

Hello everyone, Let's say there was gun and a bullet with a mass of 1kg at rest. The bullet and guns speeds were 2 m/s in opposite directions after firing if I right the equations. Kinetic energy 0.5m1v12 + 0.5m2v12 = 0.5m1v22 + 0.5m2v22 Why doesn't this equation work when objects are at rest. Mathematically I can understand but why physcially. Can anyone explain what is happening to kinetic energy in this scenario. Why does conservation of momentum equation hold in in inelastic collisions but not this one. I understand some energy is lost but why is it not affecting momentum.

I've recently been reading about these: http://en.wikipedia.org/wiki/Polywell They're a fusion reactor which is a hybrid of a few different ideas including inertial electrostatic confinement and magnetic confinement (if I got that right). They sound substantially less complicated than the much more heavily researched Tokamak design and also carry with them the potential for commercial power production. A quote from someone involved in some recent Navy research into this concept: Dr Richard Nebel commented that "There's nothing in there [the research] that suggests this will not work," but "that's a very different statement from saying that it will work…

Since a lense behaves as a set of prisms, so then a lense must also have the same prperties as prism. In a prism, the angle of deviation decreases with increase in angle of incidence. in a lense the angle of incidence of rays of a beam of light parallel to the principle axis is less at the lense surface near the principle axis but the deviation is less. why?

Hello everyone, May be the question is when something has energy and there is no resistance why does it move? Thanks