Recent content by kd001

That's exactly the problem that I'm having. As I said the relationship is definitely true: http://scienceworld.wolfram.com/physics/MagneticReynoldsNumber.html However, I haven't come across any books or other sources that explain why this is the case and what the 'additional relationship'...

More than 400 views and no one has an idea? In case my initial post wasn't very clear, I'm just looking for a way of proving that the ratio of the vector quantities on the left hand side of the equation is equal to the term on the right hand side. The expression is definitely correct. I just...

Is there a simple mathematical way of proving the left hand side equals the right hand side (see attached image)? Any help will be much appreciated as I'm desperately trying to work out exactly where the magnetic Reynolds number comes from. I can derive the left hand side (its simply the ratio...

I remember reading an article on exoplanets which suggested that when a star loses its mass, the orbital radii of the planets orbiting it increase. Apparently this makes it easier to identify such planets as they are now further away from their star. What I would like to know is, what...

Thanks. But Would 'h' be the same as 'H'? Also I believe the normalisation constants wouldn't be the same when the equation is split.

H(a1u1 + a2u2) = a1E1 u1 + a2 E2u2 H is the Hamiltonian energy operator, a1 and a2 are normalisation constants, u1 and u2 are wave functions, E1 and E2 are the eigenvalues. Is it possible to calculate the values of E1 and E2 from the above equation if everything else is given? It should be...

Thanks. That worked.

Homework Statement sinh(x) = 1 What is the value of 'x'? Homework Equations sinh(x) = (1/2)(e^x - e^-x) The Attempt at a Solution e^x - e^-x = 2 Then what do I do? Thanks

I need to calculate the mean square speed of molecules in an ideal gas. Mean square speed is equal to 3RT/M, where M is the molecular weight. But what units do I use for the molecular weight if I use 0.08206 L.atm/(mol.K) as R? Thanks a lot.

I don't see how t can be calculated without knowing v in the first place.

Homework Statement Muons, which have a half-life of 2 x 10-6 s, are formed in the Earth's atmosphere at an altitude of 10 km. If they travel normal to the Earth's surface, and one half of them reach it before they decay, what is their velocity? Homework Equations Lorentz...

Here's what I've done. I've treated the numerator as being sinhx/coshx and differentiated it to get (1/cosh2x). I've treated denominator as being 2x and differentiated it to get 2. Therefore I end up with (1/cosh2x)/2 which gives 1/2 as x approaches 0. Is this the correct answer?

Homework Statement Evalutate the limit, as x approaches 0, log(coshx)/x2Homework Equations L'Hopital's ruleThe Attempt at a Solution I can get as far as (sinhx.cosh-1x)/2x by differentiating the top and bottom separately. I'm not sure how to do the next differentiation. Thanks for any help.

Thanks!

Homework Statement A hemispherical piece of ore of radius a contains flakes of gold. The flat base of the ore is in the x, y plane and its curved surface is in the region z > 0, where x, y, z are cartesian co-ordinates with origin at the centre of the base. The gold density is kz kg m−3, where...