Lec 30 | 8.01 Physics I: Classical Mechanics, Fall 1999

[gtq838]

Yeah i was wrong about the chalk thing.... Its been said already... I stand corrected... Please stop trolling for fucks sake.

[gtq838]

Yeah i was wrong about thel chalk thinh...

[jorisewout]

His accent gave away that he is dutch

[Dave67004]

Awesome. Think I understand physical pendulums now...lecture 21 traumatised me :(

[8urfutrkin]

easy

[fthbl01]

talking about a liquid in a U-tube on youtube ...

[hodgedawelshy]

im in year 12 and im trying to understand D'alemberts theory and im struggiling

cand any1 help no hard words plz

[hrabia99332]

:O I AM HAPPY THAT I GOT HERE BUT I DONT KNOW HOW !

[MrWaffcn]

great teacher. But i am wondering why there are so few students in the classroom?

[cgxuvimr1]

these types of people are in iit?

[mani230608]

wish i had a teacher like him



[Cifrocco]

Why do so many people wonder at the way he draws dotted lines?!? Are you people STUPID or what? Geez, don't you have just a teeny weeny little bit of imagination to try and figure out just what might be going on? Is it really that mysterious and are you really that dumbfounded?!?! LOL

[DaBhaalspawn]

Ok.

Step one: grab a piece of chalk and find a blackboard

Step two: try to write a straight line holding the chalk almost vertically (with care not to make the screeching sound everyone hates)

Step three: marvel at the instant dotted line

[TKDKobioshi]

how the fuck does he do the dotted line so quickly hes dumbeldore of physics

[HunterDX77M]

8:32

How does the square root of 1% become 0.5%?

[birkenfeel]

@HunterDX77M it's the propagation of errors: to calculate the error of a dependent quantity X(Y), you take the error of the original quantity and multiply by the derivative dX/dY; for the square root this is where the factor 1/2 comes in.

[nibauAntunes]

I love these lectures!

[welderguy5]

He does the dashed lines by angling the chalk into the board so it catches and skips

[nibauAntunes]

@welderguy5 good trick!

[samuel91222]

i have a question. At about 6:25 where he is writing the equation for the moment of inertia of a rod, should not that I of c becomes 1/12 m (1/2 L) square?since 1/2 L is the distance between the centre of mass and the rotation axis.

[bubbajotbone]

@samuel91222 Whaaaaaaa....?

[fustilarian1]

@samuel91222 the moment of inertia of a rod about its' centre of mass is ALWAYS (1/12)*M*(L^2), he used paralell axis theorem and found the moment of inertia about point P by adding M*((1/2)L)^2.

[stavlois]

excellent lecture

[Tykovni]

@stavlois It sure is.

Much easier to understand than lectures I get.

Funny thing is that my 1st language isn't English ,but it's much easier to understand him than my teacher.

Thumbs up!

[atreusK]

how does the period make sense for a uniform circle like a e disk to be oscillating about its center of mass? Thinking about it, the disk would not oscillate about its center. Mathematically, the period T equals 2pi* sqrt( .5R/g). Which one's right?

[fustilarian1]

@atreusK for the disk, he modelled it as oscillating about it's pivot (because the moment of inertia he took was about point P.

[rickycax]

he is really good at his job.I do respect him.GREAT JOB

[1888junkteam]

excellent work!

[VideoMaker0123987]

i am in 8th grade and i am 14 but i get almost all of this.

[amrosik]

@VideoMaker0123987 what didnt you understand^^, the calculus parts or what?

[VideoMaker0123987]

YA kinda... his way kinda threw me off

[firemanleeman]

I love his energy for the subject.. .it's contagious! NOW!

[iamdarwingalapate]

this teacher is doing great job..is he married? maybe he was the grand son of isaac newton...i learned a lot form his lecture,..thanks sir!

[sgmachine2003]

walter lewin rockz..! It was his funny lectures & experiments (8.02) that helped me score good marks in my 12th std exams.

I wish i get a chance to meet him and say a thanks before i die.

[poolplayer999]

does he account for "fluid" masses, such as a very pliable rod, where the pivot point is not fixed?

[pinkie24]

what level physics is this?

if physics I (as it says in the title) is just general physics, then wow..

[w2wgamer]

yeah it is general physics lol it is with calculus though. my college calls it physics 251

[kingofbums5]

absolutely genius i dont know how thats even possible to be that intelligent

[mremile72]

yeah walter lewin is really something else isn't he, fantastic =)

[jcorye1]

how does he do that dotted line thing?

[gtq838]

lol, he has a special chalk holder, but you should see him craw circles free hand... almost perfect.

[neutrinosaur]

@gtq838 FALSE, dotted lines are created using a simple technique similar to tool chatter...

[gtq838]

@neutrinosaur I'll be darned. learn something new everyday

[cgxuvimr1]

@neutrinosaur great expert



[nicenow25]

@gtq838 do you have video evidence

[nicenow25]

@nicenow25 maybe lecture 25