Free space Definition and 82 Threads

I was thinking if the Higgs part would be found next year, is it true if it could be removed from materials, that you could build spaceships from such materials, you could travel with speeds close to the lightspeed, so Star Track would be a real possibility in the future ? Or do I forget...

Homework Statement Two identical particles, each of mass 1300 kg, are coasting in free space along the same path. At one instant their separation is 15.0 m and each has precisely the same velocity of 900 m/s. What are their velocities when they are 2.00 m apart? m_1 = m_2 = 1300kg at...

Homework Statement An infinitely extended cylindrical region of radius a>0 situated in free space contains a volume charge density given by: [ ρ(r)= volume charge density ρo=constant=initial volume charge density radius=a>0 ρ(r)=ρo(1+αr^2); r<=a ] with ρ(r)=0 for r>a Questions...

I'm returning to grad school for physics this fall, but I've been out of the classroom for thirteen years. (teaching music, of all things) I'm working my way through practice problems for the placement exam, but I don't have any way to verify correct answers for the problems unless I find...

I'm not asking a question of what is permeability, but rather why is pi involved in its definition of 4pi x10^-7? As far as I know, pi is generally only used whenever dealing with a circle. How does the idea of magnetism relate to a circle?

Homework Statement If the electric field in free space is E=Eo(x^+y^)sin(2pi/lamda)(z+ct), with Eo=2 statvolts/cm the magnetic field, not including any static magnetic field, must be what? 2. Relevant equation ∇ x B= 1/c ∂E/∂t The Attempt at a Solution First I calculated ∂E/∂t=...

Hi, In my physics book I have two values for the permittivity of free space: 8.854x10^-12 c^2 N^-1 m^-2 and 8.988x10^9 N m^2 C^-2 What is the difference between these two? When would I use one or the other? Thanks.

Here is the problem: In free space, what would the answer to number 2 be? Number 2 is a=((Vrk)/(1-kt))-g. I think that since there is no gravity in free space the answer is a=((Vrk)/(1-kt)). Is this correct and is my reason for it correct?

Hi Guys, This somewhat abstract concept just happened to pop in my mind. CASE 1 :- Assume a 3 phase Induction motor to be placed in free space such that both the stator and rotor are free to move relative to each other i.e. neither the stator (nor the rotor for that matter) is bolted or...

Dear Friends: Can you help me to design free space optics system link between Geostationary Satellite and Optical Ground Station?(bidirectional),Thank you in advance for any help.

Hi All, I understand that the impedance of free space, according to the formula E/H, is 377 ohms. I understand that if the impedance is high, a given electric field is associated with a smaller magnetic field but what does this really mean? What is being impeded? Also, what is the...

Homework Statement In Jackson 3.16 we have to prove the expansion \frac{1}{\left{|}\vec{x}-\vec{x'}\right{|}}=\sum_{m=-\infty}^{\infty}\int_{0}^{\infty}dke^{im(\phi-\phi')}J_m(k\rho)J_m(k\rho')e^{-k(z_{>}-z_{<})} Homework Equations The Attempt at a Solution I tried to use the...

This isn't really a homework problem, I just need to know how to do a problem similar to this one for the final and I don't want to fail, so I posted it here. The problem is: Given the electric field for a plane wave in free space: E(r,t)=E1cos(wt-ky)k a)what is the statement for w and ka...

Hi All, I'm reading about the attenuation of radio waves in space and I understand that, in addition to the normal attenuation that is proportional to the inverse of the square of the distance, there is also a loss due to the medium. This surprised me as I thought that there was no loss...

Hello I'am a fifth year senior majoring in telecommunications , and i'am considering FSO ( free space optics ) for my graduation project . i managed to obtain many books and papers covering the theoretical part . but material covering the design of the electronics - transmitter & receiver -...

Homework Statement Well, I´m doing a project about FSO (Free Space Optics), it deal with optical communication but without fiber, only by air. Then, I have already studied the transmitter (gaussian source), the channel and I know I need a photodetector APD for the receiver but my questions...

Homework Statement As in the title Why can an electron - antiproton pair not be created by a photon in free space? This question came up last term but our tutor told us that it is because there are "no stimuli", I'm sure there is a better answer than this. I seem to recall that it can...

We know for sure €0 and µ0 for free space. We know as well €r and µr for material Have theses values been calculated for stand alone particles like an electron, a proton or a neutron? Have somebody then connected theses values to an atom (of hydrogen for example) which is a combination of...

In David Bohm's "Quantum Theory" (an intro topic building up to the Rayleigh-Jeans law), he states: "We now show that in empty space the choice div a = 0 also leads to \phi = 0 ... But since div a = 0, we obtain \nabla^2\phi = 0 This is, however, simply Laplace's equation. It is...

Hi! please help me! I am having a real problem this days about my free space on my local disc C. Sometimes when i turn on my computer i find that the free space on my local disc has diminished itself without that i have saved anything on it before . This is very serious because there is at...

Sorry for not following the template but as I'm not answering a problem it didn't seem apropriate. Hopefully this is the right place to put this (it seems somewhere between introductory and advanced). Just when I thought I was getting my head round this stuff I'm completely stuck on how the...

Hi everyone, Been doing some reading on permeability lately... My question is would the permeability of free space (u0) be related in any way to the vacuum energy density or would it remain the same regardless (4PIx10-7)? For eg would u0 be lower inside the space between the Casimir plates...

Please do not answer these, just give hints A block of mass M is connected to a second block of mass m by a linear spinrg of natural length 8a. When the system is in equilibrium with the first block on the floor, and with the spring and second block vertically above it, the length of the spring...

I was alerted to low free space. It was 199MB on my C drive. I did the "disk cleanup" and nothing revealed anything more than about 400KB. That's K and not M. None of my browsers use C for cache and I don't keep a recycle bin on drive C. So I searched drive C for anything modified today...

Permittivity of a vacuum is a number arrived at beginning with a value for the speed of light in the vacuum and the permeability of the vacuum. NIST uses the term "electric constant" for what is commonly known as the permittivity of free space: Here's their official value...

Light travels at approximately 186,000 m/s. as long as it is in its "natural" environment(space)... but put it in a vacuum and things change. So tell me then... Why do we call it the speed of light still? How about the velocity of space. So now... let's discuss this... please do not lock this...

For a rocket in free space, it seems that P = mv + (m_0 - m)(v-u) where m is the mass of the rocket, v is its speed, m_0 is its initial mass, u is the speed of the propellent relative to the ship. But in solving dP/dt=0, I get that the velocity is linear in m. There seems to be a mistake...

Magnetic Dipole Moment does not include the permeability of free space? Hi, The formula for a magnetic field in a current loop involves the permeability of free space. But the formula for the magnetic dipole moment which seems to represent the flux through a current loop does not...

A very long straight wire carries current I. In the middle of the wire a right-angle bend is made. The bend forms an arc of a circle of radius r as shown in the figure below. Figure: http://east.ilrn.com/graphing/bca/user/appletImage?dbid=1161207397 Lets say the permeability of free space...

Does anyone know of a physical explanation of \epsilon_{0} and \mu_{0}?

What information does this law give us? This seems to be a different question to "what does this law mean?", which I could answer with "it describes the electrostatic force between two charges q1 and q2 separated by a distance r, the magnitude is inversely proportional to the square of the...

And why is it related to pi?