Recent content by H.fulls

Hi guys, I recently started reading/working through Scott Dodelson's Modern Cosmology in preparation for a Masters course I'm taking next year and one of the exercises has stumped me and (arghhh!) its not one of the solved ones in the back! It is in Chapter 4 (The Boltzmann equations) and is...

Have a look at theta again. You can't just set sin theta to 1.. Have a look at a diagram of the experiment to see what theta actually corresponds to

Thats not how the question is worded :/ Would maybe make more sense like that...But it definitely says by what factor do the two operators given differ.

1. Homework Statement I have two operators A^2B^2+B^2A^2 1/2(A^B^+B^A^) 2 By what factor do the two operators differ? 3. The Attempt at a Solution I believe I either have to find the inner products of them and relate them somehow or use commutation? Not sure which one! I don't...

Homework Statement I have two operators \hat{A}^{2}\hat{B}^{2}+\hat{B}^{2}\hat{A}^{2} 1/2(\hat{A}\hat{B}+\hat{B}\hat{A}) ^{2} By what factor do the two operators differ? The Attempt at a Solution I believe I either have to find the inner products of them and relate them somehow...

Homework Statement It is said that good ice skating only occurs when the ice below the skates melts. Using the Clausius-Clapeyron equation, estimate the coldest temperature at which good ice skating can occur. (Water expands 9% on freezing, Latent heat of ice melting is 334 kJ/Kg, the contact...

Take a look again at your pressure... It is 10 atmospheres not just 10. You will end up with a much smaller value for volume

Ahhhh okay! I finally understand! Thanks so much for your help :) !

Ahh okay.. is the other pair the boiling temperature and pressure for normal conditions? i.e 100 degrees and 101 KPa ?

so the vapour pressure at boiling point is the pressure I originally gave in my question?

Ah okay so the P's denote just the atmospheric pressure? I know the pressure for not boiling, but I don't know the pressure for when it is boiling! So confused by this question!

But if the pressures are the same does that not make the left hand side ln(1) =0! ?

Ah okay :) Erm..nothing probably! But I seem to recall that the ambient pressure and pressure at boiling point are the same? maybe... ? haha :)

sorry that's v = \sqrt{\frac{T}{M/L}} so f = \frac{\sqrt{\frac{T}{M/L}}}{2L}

Okay so check this diagram out http://www.physicsclassroom.com/mmedia/waves/h3.gif Thats a 3rd harmonic... So you've got 4 nodes where the string is not moving at all, and 3 antinodes of maximum displacement. Its fixed at each end, so 0m and 9m must be nodes! They can't move if there being held...