Lec 32 | MIT 8.02 Electricity and Magnetism, Spring 2002

[KClaisse2]

@cabbotron you just hold the chalk loosely in your hand at an angle and let it bounce as it moves over the surface of the chalk board.

Say the chalk board is this line and the chalk is represented by the slashes. You are going to move the chalk to the right while holding it at the same angle (maybe even rotated a bit more counter-clockwise) in the illustration below:

--> ____\\____ -->

I always see this asked on all these videos so I hope this explains it well.

[EJNewbury]

One thing that does annoy me about all these videos is that in -every- one, someone asks about the chalk line. This guy is explaining some really cool shit, and we notice his writting utensil more then anything else....

Mr. Lewin, please, for the love of god, post a video about the damn chalk line so people will stop asking, lol. I'm begging you. Or maybe, crazy thought, people could just buy some damn chalk and try it out on a sidewalk till they get it, you knkow, cause it's so importent.

[ducaticlaudia]

there is nothing special about a cos(x) in life

LOOL

[MRburitz]

2 people failed this class

[BetterRedThanDead]

at 7:05 (ish) did he really just say that there is nothing special about cosine... IN LIFE? it sounds like that every time i hear it. to that i reply lol. and i sincerely mean lol.

[PolskaUrban]

thats harvard MIT right?

[rukus100821]

@PolskaUrban completely different. research it to get your answer.

[kristiankroflin]

"They" call it transformator when one thing of one scale get´s transformed into the same one, but they don´t call it transformator when it gets transformed into something higher, then it is called motor or generator (or microphone and loudspeaker - or whatever else, mustn´t b connected with scales misnamed as electormagnetism at all) - but it´s all transformators.

[webphy6]

...when i say "go to" I mean really become a part of - as a student ;) hehehe

[webphy6]

One of my dreams is to go to a nice university in the US; seeing this video, in a way, fuels that dream ;) thanks for the post!

[scientificboysclub]

ME TOO

[navyseal100]

me 2

[picobyte]

Lollz the dutch accent is funny :)

[cabbotron]

38:15 watch out for molten copper falling on your hands, Professor "I don't wanna melt my hand no more"

[cabbotron]

I'd like to see some proof that the poynting vector "oscillates like mad." (24:17).

[cabbotron]

22:23 "You're an idiot!!!" if you choose any other coordinate system than the 'right-hand' XYZ. Well said...hahahhahaa

[cabbotron]

at 20:02 he draws a straight line by moving his chalk so fast...it actually makes a dotted line. Is there a special technique used to do this? Or does his medication cause a cosine frequency of seizures in his wrist of which he has perfect control? :o)

[theone320]

@cabbotron There is a special technique to the dotted line.

[DonQuichotteLiberia]

"There is nothing special about a cosine in life." Hah. :-D

MIT rocks, I wish they featured an exchange program with my uni.

[alanot]

In an Electric Circuits course you see that it is important to set the power supply in terms of cosine, to simplify the circuit when working with several series/parallel impedances.

[DonQuichotteLiberia]

it doesn't matter if you take a sine or cosine, just adjust phi accordingly

[alanot]

of course... that's the way for you to change between sines and cosines....

[zgr9]

holy crap i didnt know this guy taught emag, awesome! love walter lewin!

[FrozenPixelStudio]

This guy is so scary.."Can,and will be!!!" (Resistance is futile!) ;)

[CoolQuestions]

Week 1 Question

Who Is Your Favorite Youtuber?

Go To My Featured Video To Vote

[AiBuster]

why coudlnt this go up last week? my final was today

[LosAngelesCity]

UCLA Jacket in an MIT lecture haha nice :D