1 Gustavo Bagu, January 4, 2009 at 11:28 p.m.:

Dear Dr. Walter Lewin:
As I was watching one of your video lectures, the whole process came suddenly to a stop and I was addressed with the message "stream not found". I do not know to what this may be due, but I would very much like to continue watching them since I find them so useful, interesting and amusing.

What is there that I can do to solve this situation?
Thank you so much
Gustavo from Buenos Aires, Argentina

2 S.A..HADI, June 15, 2009 at 7:23 a.m.:

Dear Dr. Walter Lewin:
I am trying to download and watch one of yuor
lecture on waves. BUT I could not down load. what is there that I can do solve the problem.
Regards
S.A.HADI
From KIU GILGIT PAKISTAN

3 Ivan, October 21, 2009 at 3:16 p.m.:

The lecture is great, thanks to MIT for giving the world an opportunity to see it. I'd very much like to visit such a course in person :)

One remark - I'd expect to see a bit more math in such a lecture. For example, a couple of words on the solution of differential equation for harmonic oscillation would be useful to display those deep bonds between physics and mathematics. However, that information could have been present in student handouts or books that they were required to read before the lecture, then my remark is invalid.

Another thing I suddenly became interested in - what's that chalk that enables you to draw dotted lines? I have never seen such one in the places I was studying. Is it a special kind of chalk or is it easily made from a regular chalk?

4 Psylum, December 23, 2009 at 5:19 a.m.:

Ivan-It's a piece of chalk on a small wheel.