(2:3) The Wave Equation: Derivation (Walter Lewin, MIT)

[jesusgray922]

I want this video on my A31 phone.

[RHDB17]

he changes the angle of the chalk hes holding

i bet at 42 degrees

[Ghaiyst]

that dot technique....would be usful for getting 100 percent on through the fire and flames on expert! :) lol

[universalsailor]

It's dotted chalk. He has it shipped in from Rotterdam.

[MonicaKn17]

Wonderfully explained. And i love his enthusiasm too.

[Seracinfinity]

Fantastic lecture.

[X3QT0R]

I had a 10:48 minute long mindgasm. Thank You @ MIT OCW

[CougarBen02]

I know chalk boards are hard to find now days. but it's easy to do: hold the chalk loosely in your hand and hold it at an angle so that it's ahead of your hand. Push it in the direction of your line and it skips making a dotted line. Too easy.

[lifeDotGov]

how the fuck does he do the dotted line thing? jesus christ.. mind = blown

[goodbyelonglive44]

@lifeDotGov its probably a wheel at the point, he fixes the chalk at the back and when the wheel moves, it scratches the chalk and marks the board..that sound "drrrrrrrrrrrr" probavly sounds like it..

[mynamesnotdan]

@lifeDotGov i have no idea but its awesome lol

[nahaymath]

He owes me a month's salary: not ANY single-valued function of that form f(x+c*t) will work, but any SECOND-ORDER DIFFERENTIABLE single-valued function of that form will work! :) :) Gotta be in C(2).

[goodbyelonglive44]

@nahaymath thats hardly concidered practically conciderable

[Titurel]

Ok - that was cool...

[69erthx1138]

I had forgotten this simple derivation from solid mechanics, but when (mu/T) d^2y/d^2 = d^2y/dx^2 emerged from the analysis at 7:15 the lights came back on!

[beafraid]

Cool freakin chalk.

[basshnter912]

That's what the 5 yr/old said who is using the same exact piece on the sidewalk