Moments | Moments, torque, and angular momentum | Physics | Khan Academy

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Introduction to moments. Created by Sal Khan.
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Physics on Khan Academy: Physics is the study of the basic principles that govern the physical world around us. We'll start by looking at motion itself. Then, we'll learn about forces, momentum, energy, and other concepts in lots of different physical situations. To get the most out of physics, you'll need a solid understanding of algebra and a basic understanding of trigonometry.
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Опубликовано:

22 май 2008

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Комментарии : 362

@elle9030 5 лет назад

he confuses clockwise and anticlockwise in the end but overall he explains everything else perfectly

@88GTA 3 года назад

Tryna be my tutor? 😏

@zolanhlangulela947 2 года назад

He did correct it in the end..He noticed it

@hippo1503 2 года назад

@@zolanhlangulela947 he said “confuses” not wrong

@michellerstewart7 Год назад

I came here to see if I was crazy. I was so confused, lol

@borisjohnson32 5 лет назад

*Clockwise:* ↩️ *Counter clockwise:* ↪️ Hope this helped Edit: (1 year later) Did i seriously just tell people on the internet what clockwise and counterclockwise is?? LMAO

@kaushikkalesh1678 3 года назад

Seriously? But thanks for the good Intent

@spontaneouspotato133 3 года назад

Boris take away tax innit

@itsjustanapple5452 3 года назад

Cant you just think about a clock in your head.

@Cube_Box 3 года назад

@@itsjustanapple5452 for people who were born in the digital age and never seen a ⏰ they'll find this really helpful

@Rianajay 3 года назад

Here I am a year later laughing at what you said. LMAO

@Davidow1 8 лет назад

I hope this and all other physics videos gets updated to HD and have all their mistakes fixed. I'm still loving KA though and will keep donating!

@niconikko 12 лет назад

"It always becomes a lot easier when you do a problem, except when you try to erase things with GREEN."

@dasumma1 4 года назад

8 years ago and someone is probably seeing your comment for the first time

@samuelhugo467 3 года назад

9 now and I was just the 5th person to like it

@felixling8976 3 года назад

4:29

@EesaSalmanKakakhel 2 года назад

Nico, are you still there, how old are you

@glitchy_star_classes6276 2 года назад

Eesa Salman Kakakhel 18 years .. you?

@nmq3b 14 лет назад

"why did I write down mechanical?" lol. His unintentional humor makes it really fun to watch.

@seungseungminji 3 года назад

How did life treat you? How was school?

@nazirelahi9968 5 лет назад

You literally are my physics exam savior

@pruthviraj9917 7 лет назад

though it is helpful but presentor have confusion in clockwise and anticlockwise

@Datagnan95 10 лет назад

did he cnfused on clockwise n anticlockwise?

@SarcasticxLiar 10 лет назад

Yess omg i was so confused

@AmiraDreams 9 лет назад

yep

@Abss0966 8 лет назад

+Amira Lam. hi

@inesmonteiro7250 6 лет назад

Yes i think he did

@libinchen9899 6 лет назад

I mean he did, but he clarified the method we should use for this type of problems! 😂

@stephaniemalik6108 10 лет назад

twerk.......... now im understanding moments of a force!! thank you Khan

@leechmaster21 11 лет назад

Thanks Sal, I remember I was terrible @ this stuff in high school. Now I'm at university and I need to know this stuff for a Biomechanics unit, so much clearer now.

@BaronMorte 14 лет назад

Sal...you are the man. Thank you.

@harryshepherd4232 5 лет назад

Hilarious how you know all this detailed physics stuff yet can't figure out which way a clock-hand moves. Great video though, very helpful!

@Ridegucci 13 лет назад

mate in a short video ive learnt more from you than my physics teacher.... you made it so easy to explain..

@0113slimshady 11 лет назад

Sal I think you may have just saved my life! THANKS SOO MUCH!

@bballer10590 10 лет назад

Thank God! I'm so happy Dr. Khan made a video!!

@morvaridahmadijah6999 5 лет назад

You're amazing for refreshing my pre-university memory keep it up :D

@amaadulhaq4319 10 лет назад

U explain so nicely and clearly

@davemcquire504 11 лет назад

I'd love to see a lot of beam deflection problems using calculus. Simple span two point beams with multiple loads and cantilevers - but not all at once. Thanks so much love your work!

@singh123416 9 лет назад

god bless khan academy

@do._.daboss4828 4 года назад

Nobody: Comments: keeps saying he confused between clockwise and counter clockwise non stop Note: am I the only one who writes/says anti clockwise rather than counter clockwise?

@neelamsarma5076 10 лет назад

wonderful and a highly conceptual video......simply amazing......like ittttttt....!!!

@av_naturasmr Год назад

Moment is simply just a rotating force around a specific point/pivot. You can start with this simple meaning

@notslo 15 лет назад

Excellent teaching style. Thanks.

@theslingmethod Год назад

Brilliant explanation. We got the clockwise/anti-clockwise, thanks again! 👍

@pawpawbear1175 7 лет назад

guys he mentions that he kept mixing up clockwise with counterclockwise near the end just go with clockwise and counterclockwise as you would. he was just mixing them up on accident

@jstinlee 8 лет назад

The day that you can torque better than Miley Cyrus

@AlejandraRodriguez-rn1zp 8 лет назад

+Kun Seung Lee better than Rihanna

@Bilnuran 8 лет назад

+Clara “mylove2345” Torque Torque Torque Torque Torque he said me haffi TorqueTorqueTorqueTorqueTorque! xD

@matimuyerhutimsondlane9226 6 лет назад

True that Mr Obama

@theblunderkegs2334 Месяц назад

oh my gosh I was 4 when this video came out, now I'm in college and this guy has helped me get through calculus, chemistry, and physics many many times. thank you sir you have been a blessing in my life

@harrytuttle4069 7 лет назад

Thank you so much!

@joaonogueira3401 3 года назад

finally I undesrstood thanks Sal

@xconwing 15 лет назад

very nice, this is a review for me but your confusion of counter-clockwise / clockwise every now and then is funny, making the tutorial quite refresh and not sleepy

@mexicanmilky123 14 лет назад

Good Video, Confused about The CCW and CW parts until you corrected it at the end. But still very helpful

@OmriKipi 15 лет назад

"i don't know... lets say its 2 " - damn , did i laugh so much :)

@rhshovan 3 года назад

THANK YOU SO MUCH....

@Fywl92 11 лет назад

LOL dude! Nice lesson! I actually learn a lot + it is fun. I love it, thanks a lot, I got a hard time understand this.

@EclipZeMuzik 6 лет назад

dude you're amazing i love this!

@Aboalmaaly 12 лет назад

thanx mate!

@zckhor1778 5 лет назад

Thanks a lot!

@appletime20 11 лет назад

thanks, this helped alot :)

@YeshuaIsKingofKings 13 лет назад

Sal, you are great. Just a little correction: Im afraid that you did confuse the clock- and counter clockwise directions at about 10 minutes. But Its common sense. Best regards from Serbia

@overreactiontime6270 7 лет назад

Its actually really nice thanks

@hatemsaad3421 7 лет назад

you're just overreacting

@TheNigttimeNightmare 3 года назад

this. was. twelve. dang. years. ago. and yet his way teaching never fails to teach me : )

@thanismurugathas7497 3 года назад

until he messes up counterclockwise and clockwise. Still its all love

@guywthclss 3 года назад

QUESTION - Any explanation of "moment" or "moment connections" must start with the etymology of the term "moment" which is crucial for me when I try to understand anything. So any layperson, when they think of the term "moment" is in reference to time. A "moment" of time. So now that we are apparently repurposing the term "moment" for torque etc can you explain why it is called a "moment" to begin with? How is the term "moment" in reference to time used here or are we redefining the term specifically for physics / Engineering?

@DyastKol 6 лет назад

THANKS BRO!

@BobSmith-fg6wi 11 лет назад

thx! i understand now ;)

@renewableenergy78 11 лет назад

THANK YOU!!!!!!!!!

@christopherhan9756 10 лет назад

for the last time, clockwise = --> this way counter clockwise=

@user-um5wz6xc2e 10 месяцев назад

Hello Sir! I have a question regarding the direction of a force. How can I determine if a force is clockwise or counterclockwise? Could you please provide some guidance or resources on this topic? Thank you in advance for your help!

@ShiftnoteProductions 6 лет назад

basically the closer the object is to the pivot... the more effort ( force ) required ?

@imedyana 13 лет назад

thanks a lot.

@f8tal_156 5 лет назад

oof almost a million people saw sal getting confused with clockwise and counter clockwise xD if you view the same video on the ka website a small pop up corrects his mistake

@adamokoh4355 8 лет назад

thanks dude

@xensationss 12 лет назад

this was very good.. i get it now!!lol.. im in 10th grade and when im studyings physics for exams this is so helpful!! thanks=)

@imedyana 13 лет назад

thanks a lot for the video. great help to students like me.

@daniellaokafor6970 2 года назад

You still alive?

@Blueknightex 14 лет назад

Oh shoot! I gotta watch this! I'm so lost @ my Engr. Mechanics right now and I don't get the magnitude of the moments stuff!

@leroypetersjr.2831 11 лет назад

thanks alot

@morrispons 12 лет назад

got it!

@heavymetaldeath4life 12 лет назад

@vladuz1001 Always remember this formula: F=ma where 'F' is measured in Newtons(N), 'm' is measured in Kilograms(Kg) and 'a' is measured is Metres per second squard(M/s^2). 'a' is usually 9.8m/s^2 when you're talking about forces acting perpendicular to a surface. If we apply F=ma to your problem: 1,294(N)=m(Kg)x9.8(m/s^2) You're trying to find the mass, or 'm', so we divide both sides by 9.8 to make 'm' the subject. 1,294/9.8=m Therefore m=132Kg

@NerakCraze430 11 лет назад

oh thnx god, this video save my live!!!

@ceesingharora 13 лет назад

good' i understood'

@AngelusLabyrinth 13 лет назад

Ah! I sure wish I found this channel earlier! But thanks too anyway.

@gold_455 11 лет назад

thank you very ,much

@DOROnoDORO 2 года назад

take a shot every time Sal mixes clockwise and counter-clockwise

@ineedcoffee21 11 лет назад

Cheers Sal

@zikmir007 6 лет назад

RIP Clockwise and Counterclockwise.

@emmanueladebayo3564 4 года назад

Thanks 😊

@baydood510 12 лет назад

God bless you Sal....I have a nephew who looks like you btw

@Montecation 11 лет назад

Look its easy, just think about trigonometry: your angle is positive as it goes counterclockwise and negative as it's going clockwise. if you can just keep that image in your head, everything becomes pretty straightforward as far as the direction of torque goes.

@Nandine2 16 лет назад

oh my god, thank you, thank you, thank you.

@onlyAerik 14 лет назад

11:00 24N*8ft would work very nicely.

@kiannaking2565 6 лет назад

thanks bro!, you helped me a lot, keep up the good work!!!

@J001ean 12 лет назад

It was easy for me to understand because i saw your comment prior to watching :D

@makd7659 6 лет назад

How do you determine the unknown force as clockwise or anticlockwise? Or you just assume

@LichKing887 12 лет назад

Same with me, I really am having problems about the rotation, whether its a C or a CC.

@PianoWallaby 15 лет назад

You say clockwise and counterclockwise backwards at 11:00. But thank you for the great video[s]!

@rolandsaucier1006 Год назад

I got it ......and, as a teacher myself, I have some sympathy for the guy here. Some days are just harder than others. LOL.

@verza5042 4 года назад

The explanation is very comprehensible and we'll simplified, but the video is only available in low resolution..

@AmRKlAsHiNkOf 11 лет назад

yes dude you r right

@imogenburn7549 11 лет назад

your better at teaching than my science teacher

@carbon273 7 лет назад

just use right hand rule for the sign convention of clockwise and counterclockwise. I finished this in half the time it took time to explain

@libinchen9899 6 лет назад

Come on guys, understanding the graph and method is wayyyyy better than complaining about clockwise and counterclockwise, this this case, u just need to know the force direction is different and put them in opposite side of the equation.

@prabalpratap603 5 лет назад

Nice class sir

@pranshusingh2000 6 лет назад

Please make an HD video of this

@thetiger693 11 лет назад

If I screwed up a video explaining a simple concept such as this as badly as this guy did I would re-do it.

@onlinearcherychallenge2440 8 лет назад

Would you do a presentation on torque created on a archery shot where the hand meets the bow?

@Saudibodybuilding 8 лет назад

plz are you sure about what u said in your Example < clockwise and counter clockwise >!!!! I think you reflected the trends ........who is agree with me?

@TerenceYipMusic 8 лет назад

+Taj Alhashem as long as you are consistent with your direction, the result would not really matter.

@KeijiJohnLibadisos 8 лет назад

he's wrong .. that's not counterclock wise

@puneetpathak5840 7 лет назад

clock was screwed and so the directions

@careerlid7078 6 лет назад

@everydaynews2162 6 лет назад

Me too

@hosniashekeb2976 7 лет назад

This was great! ;) ;)

@gavincedana7781 8 лет назад

i was confused in your video.. please make it better and correct for the next time around.. Thank you..

@mashrefatarannum8983 4 года назад

Dear Salman , plz dont bother that you clouded the directions in the last case. Know that you're an amazing teacher and we love you a lot.

@jeremyenoria8933 7 лет назад

it really helped me in some points but when he pointed the clockwise and counterclockwise ...

@mcpel1055 10 лет назад

There's a problem with rotation direction but the computation is correct since it is to be equated to zero for the system to be in equilibrium.

@technodaisy18 3 года назад

For all of you guys confused wondering if he got clockwise and counter-clockwise mixed up, he didn't. That's how torque works.

@tasinal-hassan8268 7 лет назад

12:10 why are you multiplying the variable F with anti-clockwise moment 6*3?

@KeijiJohnLibadisos 8 лет назад

that's not counter clockwise 😒

@lordloki86 12 лет назад

Hilarious how he mixes up counter clockwise and clockwise, even when he acknowledges he's done it!! :)

@rahulmawa5149 8 лет назад

but it really helped me though

@SuperGamerYoBros 8 лет назад

How is that counter-clockwise ?

@mdhussain363 7 лет назад

because we get +ve value of F .. and initially we assumed that it will be in counter-clockwise

@naominene6554 7 лет назад

Lifesaver. About to write a test and you have no idea how much confusion you saved me from. @MdHussain

@mdhussain363 7 лет назад

😊😊

@JordanMorris-nzer012-_-PSN 6 лет назад

I don't get, and I have a test next week. Help pls!!! @Md Hussain

@SharkRockstar 6 лет назад

How'd your test go? And just for advice: keep searching on UTube & you'll find success. X''S

@someonetoogoodforyou 11 лет назад

Hey Sal, I've been looking at dozens of videos and wikipedia pages, but I can't find a formal proof for why M = Fr. Can you do a video describing the formal proof behind this formula? Cheers

@artroaster9886 8 месяцев назад

its not angular momentum its troque for angular momentum it will be momentum times the radius

@TheJJJJJasonXRX 11 лет назад

angled ones u need to use cos or sin to calculate... and u can assume clockwise as any direction and counterclockwise as the opposite direction of the clockwise... stop complaining, he is good

@nyashasb5273 6 лет назад

HELPFUL ONLY I GOT CONFUSED AT CLOCKWISE AND COUNTER CLOCKWISE BUT I GET IT NOW

@Scott111188 7 лет назад

If the sum of anticlockwise moments and clockwise moments are not in equilibrium and I want to find a particular force can I do this, for example: 20F - 5(10g) - 10(10g) - 15(10g) = ma? 20, 5, 10, 15 are distances from the pivot in metres, and m = mass, a = acceleration.