# Search results

1. ### Looking into Physics / Astrophysics is it to late?

If you are really interested, its never too late in science. Since you are interested in astrophysics, I would suggest you to read some books which cover the subject broadly. Start with Frank Shu (for conceptual understanding) or Carroll and Ostlie (for basic mathematical training). After this...
2. ### Trignometric and hyperbolic equalities: Why the golden ratio?

Hi! Interesting question. I have always been fascinated by the golden ratio which keeps appearing at places where you least expect :smile: Will have to think about this one.
3. ### Parallel transport of a vector.

Yes it is much clear and illustrative than the picture I was pondering with. I think I got your point. Correct me if I am wrong: I take a vector (any orientation) and move along the curve tangentially (i.e. the line perpendicular to the base of the vector always remains tangential to the...
4. ### Parallel transport of a vector.

Hi, Thanks I got the applet working. Works great. Now I need to spend some time with it and think it over. Thanks again.
5. ### Parallel transport of a vector.

Cannot run the applet : missing plug in :cry: In the above figure (previous post) the vector neither seems parallel to itself nor is it keeping a constant angle with the curve. Then how is this parallel transport?
6. ### Parallel transport of a vector.

Hi, Just to get a different perspective. Can you please explain with regards to the image on page 70...
7. ### Parallel transport of a vector.

I am bit confused now. The explanation given by tiny-tim will hold only if the curve changes discontinuously. Otherwise how do you explain the change of behavior from moving along the segment during AN to keeping retaining the old direction NB in the figure...
8. ### Parallel transport of a vector.

Hi, Thanks for the reply. Can you please explain how you can tell that the vector is parallel to itself during the transport through the segment AN (I am not able to figure that out :smile:)
9. ### Parallel transport of a vector.

Hi, Thanks. Here's my doubt. In the above figure the arrows are definitely parallel in the segments NB and BA. I am not able to understand why the same is not true for the segment AN?
10. ### Parallel transport of a vector.

Thanks. Please help me out with this. In the path 1 it seems arrows are drawn tangential to the surface. So, initially what was pointing right points downwards by the time it reaches end of segment 1. During the segment 2 the arrow doesn't change direction and reaches starting point of 3 still...
11. ### Parallel transport of a vector.

I am having trouble understanding the concept of parallel transport of a vector along a closed curve. It is said that if the space where the curve resides has a curvature the orientation of the vector will change when it comes back to its original position. Can you help me in visualizing this...
12. ### Will the universe reach thermal equilibrium even though its expanding exponentially?

The effect of exponential growth of the scale factor will be negligible at the everyday scale. So I believe even though the distance between objects will keep increasing, the structures in the universe, galaxies and atoms etc would not be greatly affected. Of course the size of the atom would be...
13. ### News Mumbai attacks: Did it have to happen yet again?

The news is deeply disturbing. Hope they can catch the culprits soon and put them to justice.
14. ### How do you parametric plot?

I think this is what you want ParametricPlot[{{4 - t, t}, {4, t}, {6, t}}, {t, -6, 6}]
15. ### Suppose i have a bucket full of water in a closed room,the water is

I believe the temperature of the room will increase. As you mentioned it a closed room and the heat lost by the bucket of water has to go in increasing in temperature of the room. This would be in accordance with the second law as now the energy is distributed among the enormously large...
16. ### Heisenberg uncertainity principle

The wavefunction of the particle and its momentum are related by the De Broglie relation \lambda=h/p where \lambda is the wavelength of the particle and p is the momentum of the particle.
17. ### Dv/dr or v/r

What are v and r? If they are distance and time , then dv/dr is the appropriate quantity. v/r will work for constant velocities only. However if v and r represent velocity and displacement and you are talking about angular velocity then v/r is the correct quantity.
18. ### Why does blackbody radiation exist?

I believe Black body radiation is a purely quantum phenomenon and cannot be explained through classical physics. It is important because of its universal nature. The intensity profile is completely Independent of the source as it comes about because of the distribution of photons in equilibrium.
19. ### How did you discover Physics Forums

Time and again searches in google for something or the other had led to PF. But I never joined that time. Few days back I was feeling bit upset on not being able to discuss physics with anybody for long time. Then in a Eureka moment I remembered PF and there I was :)
20. ### Conformal mapping of images

Hi everybody, I was looking at the following link: http://www.dimensions-math.org/Dim_CH5_E.htm The section 6 deals with conformal mapping of the image for different kinds of transformations. I tried to reproduce them in mathematica for the transformation z \rightarrow z^2. I followed the...
21. ### Favorite physics videos on internet

Hi, Thanks. Just saw the Dimensions series, the visualizations blew mind. Its wonderful. Thanks for posting this.
22. ### Favorite physics videos on internet

Richard Dawkins- growing up in the universe (theory of evolution)
23. ### Time invariance of Schrodinger equation

The Schrodinger equation is linear in time. I was wondering if that means that is not invariant under time reversal. That would be a surprise because all other microscopic laws (Maxwell's equations, Newton's equations) are time invariant. Can you please clear this doubt?

25. ### Favorite physics videos on internet

Some more of my favorites 4. The elegant universe by Brian Greene
26. ### Favorite physics videos on internet

Hi Friends, I thought it would be interesting if all of us put our favorite physics video links that are available in the internet for all to share. Here's a list of mine: 1. Walter Lewin lecture series from MIT 2. Leonard Susskind lectures from Stanford 3. Carl Sagan's Cosmos...
27. ### A question about wave function

For a free particle, the amplitude of the wave function at any point is a constant. The wave function is not normalizable, so the probability interpretation of the wave function is not applicable. All you can say is that the particle is equally probable at all the points.
28. ### A question about wave function

There are two kinds of states for wave functions: bound states and scattering states. For bound states the energy of the particle is less than the potential energy at infinity, such a particle cannot be found at infinity and the wave function goes to zero at infinity. On the other hand for...
29. ### Phase transition in one dimension

Hi, I was listening to Susskind's lecture on statistical mechanics (lecture 8). He mentioned in relation to Ising model of magnetized spin systems that there could not be any phase transitions in one dimensions. He mentioned that it has to do with the stability of the system. Can anybody...
30. ### Mathematical purity vs real world understanding

I am personally facing the same dilemma, but perhaps you are correct. Some times it is good to accept one's limitation and focus on one area at a time. I wanted to read all areas of physics, but doing this alongside my PhD is turning out to be a great disaster. It would be good if others can...