Dot vs. cross product | Physics | Khan Academy
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- Опубликовано: 7 авг 2008
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Understanding the differences between the dot and cross products. Created by Sal Khan.
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shout out to you for being a better teacher than... well.. my teachers
Best comment reward 👑
Its like when you have full interest on what teacher teaching and you listen to it carefully you understands everything clearly and thinks that teacher is the best creature ever👼
best comment reward 👑
Omg, sorry to hear that. I tbought this one sucked
@@mohammedadil7170no. Schools just pick the topic do it for a bit and move on to the next. To really understand it we need to do more selfstudy and practice stuff like questions. Schools doesn't have time to do all this and cover the entire syllabi, at least the way they go now. It's up to us. Also it's also depending on the teacher. Some teachers really have a way to make students understand thing by making sense out of things.
I was amazed with the drawing xD
Yeah me to
ikr!
Lmao
was looking for this comment haha
Dot Vs. Cross Product: Top 10 Anime Battles.
You are a mathematician as well as an artist. Well explained.
I don't know why but my middle finger goes to my math teacher.
Ashish Neupane mine too for some reason
😂 😂 😂
Dear
Never say anything bad about your teacher.because she or he deserves more respect.
@@bincybiju437 Not necessarily, respect is earned through interaction, not age.
@@zavallagarciaricardo3924 True. A teacher can't just command respect just because of his/her position. That's blind loyalty.
2:00 theta looks like ^_^
hahaha
ThX! sal
I came here just for the awesome fingers
Literally Mannn.... 15 years ago!!!.. I was just 2 year old back than!.. Amazing.!!
very funny, light hearted and informative. perfect!
Excellent! very intuitive. You have a clear way of explaining things. Thanks for the video.
This video was released when I was born and still the best explanation video of this topic!
ur not only a good mathematician, but ur also a great artist! the hand!!
Thanks for the great video :) great for general revision
Thanks very much. Didn't get the dot product for so long, and in one video you gave it to me in such an nice and easy way to understand. Very helpfull. Wish I had you as a teacher in school ha
Thanks, this answers a lot of about cross products!
You sir are my hero. I wish my Calc teacher spoke with the same clarity and english composition as your video.
Dot Product or the Inner Product between two vectors yields a scalar. Cross product x X y yields another vector....one orthogonal to the plane shared by x and y.
Wow, that was ridiculously helpful. Thank you.
good drawing for the hand ..m
8:59 indian genes took over for a second there
what
thank you so much!! I managed to get an A1 in my exams just bcos of you :)
Thank you. It is really helpful for self studying.
Lovely hand drawing. fingers took the heart away ❤️❤️
Awesome youtube channel. Subbed and thanks.
I was reading this topic for more than one hour , but ur video gave me hope !
woa that arrow analogy for the cross product going into or out of the page is awesome. I wish i had had that when i was first being taught about current and magnetism and whatnotz.
wow, very helpful!
Calm mind... excellent concept
Is it only me who thinks soo or is Sal obsessed with the word intuition 😂
2:01 SM--> SMILE :D nicee
You are my God!
If i am watching a 15 year old lecture video at middle of a night, it means the value he provides is soo deep. Thank you ❤
Thank KA my professor doesn’t even teach you are a life savor 🙏
That's good drawing right there damn
great video! helped a lot!
you are good at explaining .
now its time to upgrade and explain through animation
😆 Theta in 2:00 be like. 😆
nice, thank you
fantastic explanation
Thank you so much KhnAcademy. These are great sources!
Just found myself teo useful channels one khan academy and the other one's yours
i wish u would be my home tutor who is a ocean of knowledge
mashalla thanks allot brother.....
:) I agree.
Khan is so cool! *draw a masterful rendering of hands, wait 30 seconds, ERASE!!*
Did not expect him to be such a goated artist out of nowhere wow
Thank u man 💙
|a||b|sin() can be seen as the surface area of the parallelogram formed by the vectors "a" and "b".
Good video to share among the student
Nice!
thank you!!
8:50 mind blown
I think I broke my finger. At least I can’t take the test now!
Thank you very much sir
I waited for my physics prof to say what the cross and dot products meant practically.
That was a mistake.
Dot product = a product of two vectors and a measure of how aligned they are.
Cross product = a product of two vectors, a measure of how crossed they are, expressed as a vector that is perpendicular to both of the original vectors.
one more thing ,can u please do a video on hydrocarbons-preparation of alkanes ,alkenes........etc.pleaseeeeeeeeeeeeeeeee
Super! Thanks, Anneke
Simple and nice :) but the determinant way is better for understanding and tidy xD
Aah 240p we meet again😀
Wow great
Good job with the hand drawing
perpendicular*
'Hey Khanacademy! Sal here. Where are your fingers?'
He draws better hands on a computer than I do on paper. Gosh
do a tutorial for hand drawings lol :) :D
Thank you
13 years in the future, love you
cool
This video saved me. Thanks!
Tomorrow is my exam and i am watching it now 😳
Thank's❣❣❣❣❣❣
Should have mentioned the relationship and reason why sine or cosine is used in dot or cross product.
Thanks sir
Thanks
What do ladders have to do with this?
thanks
good
This tutorial will only make sense to those who already know how it works.
Storytale He already made separate videos on both the dot and cross product so maybe watch them instead of criticising him for trying to help people
I've got to stop looking at these videos, I really should be finishing my homework.
geometric algebra interpretation is much, much better. (a b) = (a . b) + (a ^ b) = |a||b|cos[theta] + i * |a||b|sin[theta] .... the cross product is a bad interpretation of wedge product.... (a ^ b) = i (a x b), where the cross-product obscures the fact that ordinary multiplication is related to complex exponentials.
7:22 i think its not bcos(theta), maybe its b/cos(theta)
around 7:00 it was a bit confusing cause in the sketch it seems like you are drawling a line perpendicular to b, not a (the little orthogonality square was hard to notice) and I said to myself "wait that is not possible, how didn't he notice THAT mistake?" heheh :)
3:11 test
well explained, thank you very much!
At 2:02 the theta looks like a laughing smiley.
if a (b)sin(angle) is the component of b perpendicular to a, then it should not necessarily be perpendicular to b. then Why do we say that it is perpendicular to both a and b
Hey Sal, at minute 1:04 you say that order does not matter when you multiply two vectors together in a dot product. I Know we get the same magnitude, but wouldn't the direction run in the opposite direction.
Order doesn't matter with the dot product, because all you do is multiply corresponding components, and then add them. Ax*Bx + Ay*By + Az*Bz is exactly the same as Bx*Ax + By*Ay + Bz*Az. There are no non-commutative processes in the dot product.
The cross product by contrast, is where order matters. A cross B = negative B cross A.
I could read the textbook for 2 hours or watch a khan academy video and skim the textbook
Is the first letter always the index finger?
In my school the fee is so high but the way they teach is so unworthy for that money they teach 😭
anyone here in 2019?
me
Nice fingers
So is it collinear or not
The sin Theta is going crazy 😜... Had laugh alot in 12 years........
nice hd
any ib students ou there?
happy theta at 2:00
A force = 4.85 Ni - 7.36 Nj acts at a location = 3.99 mi + 2.21 mj on an object. What is the torque that this force applies about an axis through the origin perpendicular to the xy-plane?
2
Are you starting with an assumption that we are talking vectors? I thought dot product was like this: I walk a mile in an hour, how many miles can I walk in 3 hours? Scaler times a "thing" of some kind (dot product, a quantity). Cross product: basic electricity, V=IR. Suddenly two "things" are being multiplied together (current and resistence). Commonly, vector abstraction comes later. Isn't that the essential weirdness of reality, the cross product, emergence of a new "quality"?
How do I find the sin of a smiley face?
Just ask Jesus for the sin list
easy way to remember (helped me)
dot is grayscale
cross is colored
I request Khan academy to teach on white or black board
NICCCCE