Recent content by mmh37

well, from the question, I think this is how it looks like (note that the system is arranged in the horizontal plane): Can anyone please try to help - this is really important (exams start in one week!). Thanks so much!

a point mass is constrained to move in a horizontal plane and is attached to four fixed pegs by 4 light springs. The four pegs are arranged at the corners of a square of side root2*a. Each spring has a natural length of a/2 and a spring constant a. If the mass is displaced towards one corner...

Hi all, can anyone see what is going wrong in the following problem please (this is really important, so if you have any hints that would be fantastic!) The restoring force corresponding to a change in length of the bnd between Hydrogen atoms in H2 is k = 2400 N/m, find the fraction of...

it is indeed, as the question then asks to compare this with BEC. However, the solution manual says that d = 60 um, but with the uncertainty principle I got 2.45 *10^(-7)m ?

Can anyone help me to find an approximation to the size of a He atom at very low temperature (10^(-9)K)? My attempt: At this very low temperature all electrons will be in the ground state, thus using the equipartition theorem: 1/2kT = h*c/lambda now, for the zero point energy...

thanks for this! Using the flux and the ideal gas law one can now find the pressure - the result it gives is correct!

Thank you Tide! That was indeed easier than expected! However, I can still not calculate the pressure. I was trying to do it with the relationship p=nkT but that does not work. Would you mint giving me another hint?

Hello everyone! I have trouble finding the answer to the following problem - this really bugs me. Can anyone give me a hint? Here is the problem: A vessel contains a hole of 0.1mm^2 above the liquid level (contains liquid mercury) at T=0°C. The vessel is contained within a very much larger...

I was wondering whether anyone was able to give me a hint on the following problem: Is the average kinetic energy of all particles in a gas hitting the sides of a container less, equal or more than 3/2kT? And if it is not equal how can you calculate the mean kinetic energy? I was...

Thanks for your help. I just found the answer myself. It is quite straight forward once you know that Cp/Cv = 3/5

thanks for this! So in the first part I will simply state the peviously derived equation for p: p/p_0 = exp(-mgh/kT) In the second part I still do not get the correct result. Would you mind giving me another hint? My attempt: T is not constant since the expansion is adiabatic from...

I got stuck on the following problem, which is very important for my exam preparations - would anyone mind giving me a hint? A balloon of Volume V(0) is tethered to the ground using a light cable. It is filled with helium gas of density rho (He). At ground level the pressure and density in...

thanks very much! Those links are really good and helped me to see that the vetor of an arbitrary point on an ellipsoid is NOT equal to its normal at that point! :smile: One other quick question: the normal that I had initially given was NOT normalized. grad (psi) = (2x/a^2, 2y/b^2, 2z) =...

Well, if a = b =1 then it would simply be a sphere, wouldn't it? And for a sphere the normal vector is simply the vector x of a point lying on the surface of the sphere. Wouldn't that be the case for an ellipsoid as well? i.e. a point on its surface is the normal vector at that point? I...

Hello! I am trying to find the normal to an ellipsoid of the form x^2/a^2 + y^2/b^2 + z^2 = 1 What I did is the following: Let psi = x^2/a^2 + y^2/b^2 + z^2 then grad psi (and thus the normal) is: grad (psi) = (2x/a^2, 2y/b^2, 2z) = n Could anyone tell me whether that...