More on moment of inertia | Moments, torque, and angular momentum | Physics

More on moment of inertia | Moments, torque, and angular momentum | Physics | Khan Academy

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8 жыл бұрын

In this video David explains more about what moment of inertia means, as well as giving the moments of inertia for commonly shaped objects.
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Пікірлер: 122

@saifsayed5019 4 жыл бұрын

I am an engineer having 7 years of work experience in Structural field and today's the day I actually got to know what Moment of Inertia literally means.

@gilbertwamichwe1190 2 жыл бұрын

Welcome to the club

@adityagopinathan7791 2 жыл бұрын

Then what your where doing last 7 years without knowing how to balance the weight equally

@hrn8935 2 жыл бұрын

hol up

@YashodhanReddy 2 жыл бұрын

This is the reason our country is still "developing" These "dumb" people get jobs but don't know what they are dealing with..

@AdiPrimandaGinting 2 жыл бұрын

I know you mean it as something funny, but it is actually something being dangerously very ironic

@vishnuprasadha4449 6 жыл бұрын

Dave you just saved a man's CGPA

@trevor7097 7 жыл бұрын

"If you don't know Calculus that would just look like witchcraft to you." I don't know why anyone would need a better reason to listen to these lectures. I laughed audibly enough for my neighbors to be concerned about my well-being. 10/10 would play on loop.

@rockyk6805 5 жыл бұрын

ahhahahahhah damn ur comment made me laugh a little too hard too

@nrgaming5849 3 жыл бұрын

Trevor loop means

@thetaiman5351 3 жыл бұрын

Had the same reaction and went to look through the comments to feel validated. now I am.

@zafrizulfi 4 жыл бұрын

My professor has a Ph.D., but still, he didn't explain like this. He has 3 hours per week to teach.

@Born2Losenot2win 4 жыл бұрын

Hahaha same, welcome to the bigboys study hall

@mrpee2482 3 жыл бұрын

Okay ... So what ?

@Born2Losenot2win 3 жыл бұрын

MR Pee they are not meeting up with the standards even though they are getting payed by the standards, Basically the tutors on KZfaq deserve more than this and people who don’t do their job right don’t

@mrpee2482 3 жыл бұрын

@@Born2Losenot2win Okay

@bradvincent2586 3 жыл бұрын

@@mrpee2482 so it is absurdly pathetic that countless college professors are incapable of communicating basic principles in their field. Maybe 10% of my professors have been reasonably good

@Boleniana 6 жыл бұрын

This is really useful, thanks! I was having a hard time understanding what exactly this was, then someone in upper year physics recommended this. Also, thanks for having closed captioning. I'm watching this on a library computer, and you can't easily get volume with that.

@nandha0150 7 жыл бұрын

Excellent explanation. Thanks Gratitude from India :)

@ankitaroy759 7 жыл бұрын

Thank you!!!! , khan academy has always been a life saver for me.

@melodynamics9957 8 жыл бұрын

I like the way u teach! Clarified all my questions!! thanks :)

@cowgate 3 жыл бұрын

I'm quitting uni and just watching your videos now man. You cover this in no time but I'm sitting in 3 hour lectures? 🙄. Thank you!!

@Slime5276 6 жыл бұрын

Very well explained! Thank you so much.

@soramin1599 3 жыл бұрын

u just made my life 10times easier. i wish u were my professor in physics

@aliciapang9006 4 жыл бұрын

I am about to literally drop out of my college and major in interpretive dancing or something IDK.

@ProlificPianist 3 жыл бұрын

This helps so much. My teacher & book have been throwing different values of inertia around with zero explanation or what the heck the significance of a point mass is. While I still need some more work with it, this has cleared up so much of the mystery as to why 1/2, 1/3, 1/12 and so on.

@larrynmcmahan9536 4 жыл бұрын

I saw this video, and when I saw the collection of point masses, I said "Hey! This is just a Riemann sum," I can figure by just integrating all the "point masses" together. I was able to verify the equation of I for a sphere this way.

@bantehromarick5053 Жыл бұрын

Thank you so very much. Ur teaching method is so dynamic and clear. Please don't stop uploading. 🙏🙏 Great video

@alfanalarabi1137 7 жыл бұрын

this saved my life, ty

@FLstudioProjectfiles 6 жыл бұрын

I am preparing for indian embassy examination from you channel😃😃 I appreciate your help. Thank you very much.😃😃

@marufhasan2516 7 жыл бұрын

Great explanation to understand.... thank you... hope to get more...

@Bobby14221234 5 жыл бұрын

Would be nice if you back up your lectures with calculations when you say inertia becomes 1/3 or 1/12 ..

@marthalatorre2383 2 жыл бұрын

Excellent video, very good explanation. I have a question: what are the differences between the MIM and the Volume Moment of Inertia?

@renevega2 6 жыл бұрын

Very helpful. Thank you.

@albertwood8836 3 жыл бұрын

Great explanation! And I'm actually happy that you didn't do the calculus, so i can do it myself...

@SHwao123 3 жыл бұрын

It's been a great help to study kinetics.

@sonofquebec 6 жыл бұрын

Thanks that was very helpfull !

@vj9995 7 жыл бұрын

thank you my ap physics teacher is useless

@Nik-wo7hk 7 жыл бұрын

vmar same my teacher cant solve some of the easy problems

@ilmihaqim3186 5 жыл бұрын

well, my teacher is smart genius, the problem is he thinks everyone in class is a genius. SO, we can't catch up to his pace...

@sophiem7770 5 жыл бұрын

ilmi haqim abdul nasir lord I know the feeling- everyone in my class failed a test and he said Aw Damn Sucks To Suck and moved onto the next unit.

@user-fp5xz9mo3p 5 жыл бұрын

2 years later this video saves another student's life :)

@chansam4917 4 жыл бұрын

Well, my Math teacher used 3 months to teach all the thing that we are supposed to learn in this whole year, its like one chapter one lesson. And everyone failed the exam beside those insanely smart students. Than my Math teacher be like, I know you guys got this, all of you are smart, just pay more attention so you can pass. -_-

@sanidhyasharmaji3422 8 ай бұрын

You don't know what have you uploaded my dear you are God of physics for me from now❤❤❤❤❤❤❤❤❤❤❤❤❤❤

@Mohammadalhashash 6 жыл бұрын

Nice explanation, thanks alot

@jackbrujali5372 2 жыл бұрын

Bro this is really helpful, thank you

@SQUELCH-zj7il 4 жыл бұрын

Moment of inertia for a solid beam and hollow beam please!! There is nothing about this that is very helpful on youtube! Thanks..though i have a wee test on this on Monday

@phylipeesposte8906 5 жыл бұрын

Thank you!!!

@AtagherUsha 6 ай бұрын

This is really amazing

@AbuSayed-xs5jn Жыл бұрын

Grateful explanation

@davisjohn1517 6 жыл бұрын

THANK YOU

@pappin7423 3 жыл бұрын

great content, thanks alot

@Hari-_-______-137 2 ай бұрын

We are not dumb teacher's teaching makes us to feel that we are dumb

@SuningH 2 жыл бұрын

omg brilliant!!!!!

@faarisalam3900 5 жыл бұрын

You just saved my career! Thank you!

@cornationboot8690 Жыл бұрын

@@huzaifaabedeen6509 nah just a student

@fathimafarah767 Жыл бұрын

Thank you very much

@CillianMurphy. 7 жыл бұрын

Thanx sir

@speakingbooks3727 3 жыл бұрын

In this video they discuss about Mass moment of inertia, but didn't mention that. It should be mentioned that mass moment of inertia and area moment of inertia are different.

@Zhujiayi7 3 жыл бұрын

thanks david

@hiexpressdoral7714 5 жыл бұрын

Very helpful explanation and example. Great work!

@mrlipton4571 Жыл бұрын

thank you so much

@pixelrabbit261 3 жыл бұрын

I can't believe I' saying this, but could you point me in the direction of the calculus for this? Great video.

@briarmahamd2767 4 жыл бұрын

well done

@kaleab27 4 жыл бұрын

Thanks

@ucontrol7858 Жыл бұрын

thank you .....what is the program you are using?

@Igorinlondon 5 жыл бұрын

I would like to make a device to measure the moment of inertia of a bat or tennis racquet in an axis 10cm from the end of the handle. Can anyone help me? If necessary we can use arduino as devices to measure acceleration and angles. Thanks

@jordankhadafi6416 6 жыл бұрын

@galaxyfr3sh 6 жыл бұрын

Freshman in college trying to take physics- if you take the integral of the general equation of inertia, i could swear that you get I=(1/3)*mL^3 and when changing the axis of the rod, you should be able to use the same integrated formula but just divide L by the farthest points if the farthest points are equal on both ends

@groyt541 6 жыл бұрын

You have to divide the mass by L in order to get that fraction of mass in each little slice you're adding up

@rainGod81 3 жыл бұрын

Thank-you

@alhabibahmed6440 Жыл бұрын

Thank you❤❤❤❤ so much ❤❤❤

@zeinabmohamed1668 Жыл бұрын

Think you

@nitingupta4k 4 жыл бұрын

what if the center of the mass is on the center of the rotation axis?should we take r =0

@harjassingh388 Жыл бұрын

How moment of inertia of axial fan can be calculated

@yjmsniper 4 жыл бұрын

What about the second moment of inertia for deflecting a beam?

@carultch 2 жыл бұрын

It is a misnomered term, that has nothing to do with inertia. A better name for it is "second moment of area". It is a concept that is analogous to the moment of inertia, except you replace differential mass in the integral, with differential area. It is a property that indicates the geometric stiffness of a cross section to support a bending load.

@jordanwinslow978 2 жыл бұрын

what is that app? please

@8cec 7 жыл бұрын

Please dont stop making these awesome videos !!! = ]

@walidzein1 7 жыл бұрын

i have a test on monday and i really need help ,do u have old physics test about the momentum angular momentum thank u

@oximas-oe9vf Жыл бұрын

what exactly are we taking the intergal of ?

@gabewinter9406 2 жыл бұрын

At first it seemed counterintuitive given torque/moment increases with distance, but imagine being spun on ice skates holding an object close to you or farther away.

@alienproductions9679 2 жыл бұрын

Just” learn calculus “ he says it so easily

@mohitdhadwal9840 4 жыл бұрын

Sir, moment of inertia for a disc or hollow cylinder is 1/2 mr^ but whole mass of the cylinder is distributed at a same distance that is r so why it is 1/2 mr^ not MR squr

@maxyousofirahimi4555 2 ай бұрын

why is the distance squared?

@bluesapphire3615 2 жыл бұрын

But sir a point mass never rotates. Then how can we say that this point mass is rotating?

@mattasaikiran4812 4 жыл бұрын

Sir can you please explain me ,how moment of inertia of circular section of diameter D is {(πD^4)/64}

@ahusain03 3 жыл бұрын

Actually in this video they discuss about Mass moment of inertia , {(pi.D^4)/64} is area moment of inertia.

@carultch 2 жыл бұрын

That is a different kind of "moment of inertia", that really has *nothing to do with inertia*. A better name for it is "second moment of area". It is called "moment of inertia" because it has a lot of properties in common with mass moment of inertia, but the essential difference is that dm is replaced with dA. In other words, instead of using a differential mass element in the integral, we use a differential area element. A better name for it that is also used, is "second moment of area". An application of the second moment of area, is as a geometric measure of the stiffness of a beam cross section. This term, along with Young's Modulus, gives us the beam stiffness term.

@clemsmith2253 2 жыл бұрын

What is inertia telling us. I have to find inertia in a wood beam and I end up with 1230 in cubed. What does that mean. That 1230 cubed of the wood beam is the minimum for it not to be overturned? but at what force?

@carultch 2 жыл бұрын

Which "moment of inertia" are you talking about, because the term is used for two unrelated concepts? Moment of inertia as discussed in this video has the units kilograms-meter^2. The other kind of "moment of inertia" that should really be called "second moment of area" has the units meters^4 (or other distance units). Moment of inertia in this context, refers to the mass moment of inertia, which is a body's resistance to a change in state of rotational motion, that when multiplied by angular velocity gives angular momentum. It is a property of mass, shape, and distribution of mass. The other concept is the "area moment of inertia" or "second moment of area", which has *nothing to do with inertia*. This is purely a geometric property of a cross sectional shape, that indicates a structural shape's geometric stiffness against bending. The product of the second moment of area and Young's modulus, indicates how stiff a beam cross section is, against bending. This combination of factors relates bending moment to curvature of the beam. The reason it is called "area moment of inertia", despite having nothing to do with inertia, is that it has a lot of properties in common with the way we define mass moment of inertia. The essential difference is that we integrate relative to an infinitesimal area element dA, instead of relative to an infinitesimal mass element dm.

@rinesaajdari8316 Жыл бұрын

I am guessing that for the moment of Inertia for the cylinder you should have to take the integral of m*r² for dm. This should be 1/2m²r², why is the mass not to the second in your video?

@wannabe-dev 2 жыл бұрын

one question, you keep saying "if you do that integral", but what integral? i would actually know how to solve cause in my physics exam i dont have acess to any paper saying what the moment of inertia is for which case :/

@amansourav9963 5 жыл бұрын

why is I proportional to square of radius??

@carultch 2 жыл бұрын

Because mass that is farther away from the axis of rotation contributes to its angular momentum in two separate factors. Angular momentum is r cross (m*v), where r is the distance from the axis of rotation. For a rigid body, the tangential velocity is proportional to radius as well, via the angular velocity. Both of these factors together, mean that the radius is squared in the moment of inertia definition.

@balkdermins1528 4 жыл бұрын

what sofrtware and device do u use to make your vidz

@mohammada4523 4 жыл бұрын

I suggest you learn calculus

@splashtech7093 Жыл бұрын

4:31 4:33 for

@quantumaravinth 6 жыл бұрын

7 people who disliked are people who are the living testament of “madness”

@amenassefa 6 жыл бұрын

Awesome educational video and an even better joke... "If you don't know Calculus that would just look like witchcraft to you." hahaha

@varunkota1289 6 жыл бұрын

isn't this supposed to be the other way? mass away from centre will make easier movement. for example we can close/open a door easily if force is applied away from the hinges

@khaledyasser8293 5 жыл бұрын

Imagine trying to swing around a jug of milk tied to the end of a 10m string vs trying to rotate it when it's in your hands (both cases you're the axis of rotation)

@kkikkodan 5 жыл бұрын

No . That's a completely different concept