@chrisjohnston2043

Amit Mahajan, I realize that this is an old ass comment, but I can't let that slide. You can't treat second order derivatives as squares by "squaring" both sides, that's why the second order derivative operation is d^2x/dt^2, to signify that squaring it does not turn a first order derivative into a second order one.

@DoctorFastest

It looked like his string was a spring of some kind. But it works with a normal string, too; it doesn't have to be able to stretch. 

 The only catch is that the string has to be heavy enough that the air resistance is negligible compared to the momentum, and that the string be flexible rather than stiff. In other words, air resistance makes it so this won't work for a piece of thread, and stiffness makes it so that it won't work with a thick cable. But for most strings, a good approximation.

@kamiltoktas4897

That line at 4:36 is flat as a ruler. Wow.

@suvratsharma8817

someone please tell me at about 1:11 when he tells about the shifting of the graph .......i dont get that how you get to know where the graph will shift or even if it will shift in any direction......im confused , somebody help ....please

@optimusimperat

brillian lecture

@RbtV92

alright thanks Mr. Lewin, now I have more questions than answers, just how I like it. 

@shahramkhazaie

Dear friend, the term "d2y" that you have multiplied to both sides of your equation has nothing to do with dt2 (dt squared), i.e. d2y is not "dy squared", that is the second derivitive of y with respect of a variable that is not precised in your calculations ...

@RDash

I'm jealous of his students since they're being taught by the God of Chalk. we are mear mortal peasants in his presence

@hamsterpoop

You are just manipulating arbitrary symbols to reach an answer that you already know. Your wave equation contains no information about what "v" depends on. Without that, you can't use it to model any phenomena.

@GGRSC

awesome

@roygbiv146

thanks

@ashdeash

I am in love with u genius : )

@lovuami

v= dx/dt
v2 = dx2/dt2
1/v2 = dt2/dx2
1/(dt2*v2)=1/dx2
d2y/(dt2@v2)=d2y/dx2

there is no need for any string 

how strange, kindly tell i am new to this