Moments (part 2)

[noor37130]

thank you - for this revision

I use to find moments very difficult to come across

you don't know how many people you are helping by providing this video -

keep providing more...

[goldensilverstar]

WHAT IF U HAVE TWO FUCKIN WEIGHTS PULLING DOWN, ONE ON LEFT AND ONE ON RIGHT?

[goldensilverstar]

Lol at his phone, i thought a train was gonna hit him

[AvinashNico]

Thank You very much for what u are doing, this was really helpful :)

[x0xktbby]

@5:21 Bless you.

[munchuful]

ITS A WOOD TABLE LOL



[goldensilverstar]

FUCK, he burst my eardrums with that fuckin sneeze, nearly shit my pants, thought someone behind me sneezed at my face, fuckin hell ....

[Qrawzseg]

That is NOT a book I'd like to carry around. Fuckin' heavy.

[skylit93]

yes , clockwise and counterclockwise again :) . .

[1300t5]

Omg ty.

[lilfro2009]

lol blowing out my sneakerss

[BarcaB0y10]

bless you :)

[FastFiveForever]

Man, we all appreciate what you're doing for us KhanAcademy, and i want to personally thank you as you got me through with chemistry, biology, and now hopefully, engineering. Thank you very much bro!

[guanatail]

whoa my ears almost popped just now when you sneeze. stupid sensitive headphones :(

[dedly13]

holly crap i love your vids

[niconikko]

That was the police who's calling. They are suing Sal for sneezing in the video.

[078matthijs]

that was one loud sneeze!

[insanitaruisPH]

i have learned soo much, tnx

[AZNKC]

i was stuck on an assignment question like this... thank you for clearing it up for me

[anna53ful]

Merci!!



[xrayguns]

WHO WAS PHONE?!

[dancapo1129]

THANKK YOUUUU :-)

[cnhsmcl]

you blew out my ears... ouch!!! im using head phones!

[scarlett96ful]

@khanacademy Hey. Is there a difference if you use the other leg as the pivot?

[NothingAtAllXD]

Heads up! Brace for 5:20 :)

[whatever3009]

what is the difference between moment and torque?

[whatever3009]

@Balajimt torque and moments are different, you dont seem to be aware of that, all torques are moments but all moments are not torques. even though the difference is subtle it is extremely important in several situations, it would be great if Sal can make a video explaining the subtleties.

[Balajimt]

@whatever3009 hey thanks!!!!! now i came to know more about moments but it would still be gr8 if sal can make a video about it!!!

[Doomzdayxx]

Damn dude, you sure bungled that up

[rotflmaopmpqxyz]

Instead of counterclockwise vs clockwise, can you also say that the net torque up on one side equals the net torque up on the other side or the net torque down on one side equals the net torque down on the other?

[angiesm89]

@rotflmaopmpqxyz

yeah there is another way of doing this :) u treat the table top like it's a ruler or something (from last video) and you use the centre mass as the axis of rotation and you can solve the problem by doing the counterclockwise versus clockwise forces: fd clockwise =fd counterclockwise through simultaneous equations. I find that is a nice way of doing it :)

[imcrazydoicare]

Thank you.

[waleedahmadnabeel]

i really appreciate ur videos...

there should be some comlicated moment problems solved as well.

thanx a ton!

[shawdyKK]

thanx............ I finally understand it

[5partan187]

Thanks! the way my teacher taught me this confused me, but now i realize how simple it is :)

keep making awesome videos :)

[ghettogazz]

hi could you make a video about shear forces and bending moments and drawing the diagrams for them

[hossamrida]

dude, U R AWESOME!!! like seriously u helped A LOT! thanks man, ur my hero!

[toiya666]

damn the phone,nice dude..loving moments now

[mrvlhs]

I don't think you can calclulate momentum with a box because of the contact surface being so extended, it isn't the same thing as calculating it with a "point force" wich has virtually no surface (like say the tip of a finger in a pencil).

Can you confirm?

[bustdakap]

@mrvlhs i think we are assuming that the force acting on the table from the box is acting from the book's center of mass. which is also why sal drew the distance from the axis to the "middle" of the box rather than from the start or the end of it.

--> reduce the object to the object's center of mass.

[mrvlhs]

@bustdakap Nice, thanks. Too bad it took 6 months for someone to answer this lool :)

[aminh896]

im confused

[DishHeads]

i have a question please help me out ... lets say i have a steel metre rule that weights 10 N. It have a pivot on the 0.40 metre mark. In such a case where will the weight of the ruler act ? It is obvious that the ruler is going to rotate clock-wise but how can i use this to balance the ruler and the moments and stuff ? will all of its weight act on the centre of gravity ( where the weight of the object is supposed to lie) or will this be a 40-60 split and how? PLEASE HELP ME OUT I'M DESPERATE

[melrobRTF]

5:21 is lol XD

[dmnunez1]

you forgot to mention 1 CRITICAL assumption, you need to assume the body is ridig, that is there is no deflection either rotation or translation due to applied loading. Essentially you have an indeterminate problem and you assumed it was simply supported with 0 rotational restraints at the boundaries. If nothing is assumed about the rigidity of the table then the actual static decomposition involves solving the system through indeterminate methods. understanding assumptions = correct models

[wells046]

"I'll draw it in wood; it's a wooden table". LOL!

[Patchsixty9]

Really helpful, thankyou!

Keep up the awesome work :)

[MarsBandit]

What about the other two legs on the table? How would you calculate the force on the left and right rear legs. The force is distributed to them also unless this is a two legged table.

[Randomvirusprime]

LOL huge Sneeze, this video really helped me out thanks

[kevhunt2]

I have seen only part of one video so far, Moment(2). I am very interested in online learning. Would it take an inordinate amount of time to substitute video made from a slide show (with narration), in which you use text fonts instead of (sometimes illegible) handwriting and you create a script and read from it instead of talking extemporaneously (with mistakes and corrections)? As a learner I would prefer that.

[lamb2k]

Cunt, lol. Keep up the great work khan!

[Nazthehellraiser]

@kevhunt2: shut up troll

[TuningAnApple]

@kevhunt2

Might as well just buy a textbook.

[woo216]

@kevhunt2 shutup you piece of shit dont try to make sal feel bad you stupid fuck he quit his job for you stupid rat

[bejatz]

thanks for helping us

[DaK1LL]

Its hard hard to focus when you when you repeat everything you say a million million times times times

[RogerTiger]

great videos... sincerely

just one question, can you put a video about center of mass of 2 objects with diferent mass, and know how to calculate it?

thanks

[night5life]

do you mean newton's universal gravitational law?

[RogerTiger]

no, just how to calculate the center of mass of amny objects, not its gravitational atraction.

[xlwaiyiplx]

nasty snotty sneeze

[rinwhr]

Taking an online course atm, it was so confusing even though it had better pictures than you have.

5/5

[chyzz77]

Excellent MCAT review!! Do you teach any organic chemistry??

[erinashleyx]

same thing, i'm also using this for my MCAT, hehe.. i WISH he did organic..... maybe email him and ask?!? :p

[wretcherwretch]

I'm doing the same right now. Haha. Hope ya did well :)

[elementoxygen]

@chyzz77 He does [right now in the future!!!] xD well like actually 2 years

[M3Eshow]

that sneeze really did hurt the ears haha. good video!

[healthyforyou]

What happens if one weight is on the edge of the table, rather than between the two legs?

[OmriKipi]

just learn something that 4 hours lecture didn't managed to do , thanks :}

[ChillerPhil]

Nice Vid! I'm learning from you more than from school!

[fpseli117]

@ChillerPhil me too this guy is great but i wish he could do a little more complicated examples

[anava84]

gesundheit

[sowandpigs]

Thanks for posting enjoyed the video

[Barnekkid]

Not confusing at all and I really appreciate the straightforward approach.