29.3 Moment of Inertia of a Disc

MIT 8.01 Classical Mechanics, Fall 2016
View the complete course: ocw.mit.edu/8-01F16
Instructor: Dr. Peter Dourmashkin
License: Creative Commons BY-NC-SA
More information at ocw.mit.edu/terms
More courses at ocw.mit.edu

[@ayushraj7254]

U taught this topic better than most of the teachers in Indian coaching who who prepare us for iit adv and stuff.
Thank u😗

[@awsomecube0078]

Bruh I’m here for the same purpose

[@Freakybananayo]

clean explanation and straight to the point. thanks

[@sarthakthememegod]

Thanks a Lot Sir, You made is so easy, as I saw a lot of derivations which has no explanation for dm

[@Qwertyuiopasdfghj771]

can't concentrate on the physics cause his backwards writing is too impressive

[@mitocw]

He is writing normally but the video is flipped. You are now free to concentrate. ;)

[@MurasakiBubble]

OMG.....all this time I thought they were writing backwards lol!!!! Mind blown

[@gabriellasut5980]

Mind blown for the 2nd time

[@user-rm1jm7pt2f]

@@mitocw still impressive tho

[@sudarshann7194]

@@MurasakiBubble it's russian technique

[@tlili3990]

thank you! you explained it way better than my teacher did

[@harshalshinde9343]

Why we have taken dm x r^2 only as difinetion of MI of rotational disc

[@itsmorbintime3746]

woah very nice explanation

[@ratulhasan7136]

MIT: making worlds best tech people
Also MIT microphone: we use raw audio with noise

[@virupannamedikinal]

Thank you so much Sir

[@raghavendarb3101]

How do we calculate if the disc is inclined at an angle to the vertical?

[@abhishekmeghwal6663]

Thanks

[@nevilholmes5900]

thanks

[@moo9950]

Since total mass is constant why couldnt we have integrated like this m ∫ r^2 dr from the definition of inertia

[@MyNameIsThe_Sun]

The mass of the total disc is constant however when we consider smaller mass elements the only thing constant is the mass 'distribution'/'density'. So you can't take dm out of the integral!

[@venky543211]

Sir can we slove moment of interia of a circle by considering triangle strip. If can please tell me how to slove

[@Marjiance26]

If you want to compute that I think you're gonna use how you compute for the area of a shape in polar coordinates, so you start from θ=0 to θ=2π and then do the rest

[@PanioGuitarCovers]

2:51 How can you say that the 2nd order differential dr is zero as dr approaches zero but the first order differential remains unchanged?

[@rangerbeast]

for the ease of calculation he did that

[@pamelaabede5535]

Considering the fact that dr is very close to zero, dr^2 can be approximated to 0 because it is way, way smaller by the same factor dr, which is already extremely small.

[@mognokhan1701]

Use a calculator. If r = 0.001 then r^2 = .000001 and so on and on. You can see that dr^2 will approach 0 within that limit.

[@coderanger7708]

Why should r be the integration variable, why can't m be the integration variable?

[@LerAnd-hm9fe]

Isn't the mass constant? Maybe that's why.

[@kingk3302]

The DM is the tricky part

[@abdulsbadr]

How are you writing this ...I'm confused! Are you writing mirrored or flipping the image?

[@final_motion]

Rotate 90 degree to left /right

[@chirag9159]

This is wrong,,,Icm of disc is=MR^ 2/4

[@kelvinadimas8851]

no, its 1/2 mr^2

[@Lucas-yh5zz]

i'm kinda late but 1/4 MR^2 are the momments of inertia tha correspond to the x and z axis that are parallel to the disc while 1/2 MR^2 is the momment of inertia of the y axis which is perpendicular to it

[@theknight4460]

Thanks

[@Alpha_10206]

thanks