Introduction to work and energy | Work and energy | Physics | Khan Academy

[@Someone-cw9jj]

Stop reading the comments and pay attention to the lesson.

[@anti-fangirlfanclub4776]

Thames .............

[@restrorekha5891]

Lol thanks

[@Amanda-wx5ck]

Thames 😂

[@teumeyeongwonhi4613]

HAHAHA i'm reading comments while Listening. Now I realized that I need to pay Attention. Thanks for advice😂

[@Budsport_TV]

Thames ty

[@Raskolnikov2055]

May the Force be with you.

[@Yoda-vv6ev]

I approve this

[@mosesvalentin1600]

I love my work too much buddy

[@MizzHoward23]

may the force be with you

[@whattheduck2106]

may the force be with you

[@alejandrocacho1772]

no way... today is may the fourth

[@218Flow]

Khan Academy - "looked it up on Wikipedia".

[@leoscarpoli1nonly]

LMFAO!! Exactly what I was thinking

[@aryankinge2295]

special

[@zylnexxd842]

So?

[@nickrr3626]

Title: "introduction to work and energy" Khan: "I'm not gonna introduce you to the concept of work and energy"

[@greenday94591]

now*

[@junng6848]

He said “NOW”

[@onepunchben]

Sir, I owe you so much. You have been my professor through out most of my math classes.

[@lydia4095]

Thanks

[@Dundertaker]

Please continue making videos, even for old topics. I always look back at all your physics videos every month to just revise myself and every time it helps a lot more than it did the first time.

[@tofoo72]

Ancient Comment Acquired 😱

[@dhruvchaudhary8054]

Why are u doing nowdays..?

[@arthurgames9610]

@@dhruvchaudhary8054 👆

[@PhysicsOnline]

Very clear descriptions here that have really helped the students I teach. Thanks.

[@marcopoloabenes6275]

I have exam today,I hope I'm not gonna fail

[@starheart1633]

Marco Polo Abenes how did ur exam go? I have mine tomorrow and am scared.

[@tanaygupta5310]

My physics exam is tomorrow and I am too scared.😓

[@abdelrahmanashraff4027]

hey bro,did you pass?

[@tanaygupta5310]

Abdelrahman Ashraff Passing marks were 32 and I scored 32.😁😁

[@abdelrahmanashraff4027]

Tanay Gupta wow congrats bro Khan really save a lot of ppl

[@mantistobogganmd2865]

jesus, this came out in 2008 yet he has a better mic than most tutorials in present day youtube

[@ltmsocial]

ong

[@chanachon56]

"Now, I want you guys to have the most accurate definition available so I just brought them from wikipedia" Wait WHATT???

[@kushtheemsft2000]

lol

[@like2upload3videos]

+Nam Chanachon Late reply but it was a joke .

[@earendilthebright5402]

Wikipedia's definitions for the sciences and mathematics are pretty spot on, they actually often far more rigorous than the average student requires.

[@like2upload3videos]

No that's a horrible misconception. Wikipedia is absolute trash and you should NEVER trust the information there because anyone can edit it. You can always just check the answer to that math or science problem on different, more accurate sources.

[@earendilthebright5402]

EveryExperience-A-Lesson that is not my point. If you're using Wikipedia as your only resource then yes, you are a moron, but that is not its purpose. it's supplementary​ material. A good example would be the definition of a rational no.

[@darienrampersad4062]

You might be the best teacher that I've ever learned from. Thank you so much for your amazing ability to explain formulas!

[@LN_06]

You sir, have made me understand physics. This will help me on my final exam in 2 days :) Many thanks.

[@HamzaLabshAbazid]

how did it go?

[@TheCricketer15]

man, im relying on you and your videos now to pass my physics finals cause i have been skipping so much lectures at uni..

[@musicaldarpan629]

Dude.. did you pass 😢

[@tofoo72]

@@musicaldarpan629 We don't know.... we might never know ;(

[@SomeGlasses]

Did you pass?

[@RanveerSingh-sv9co]

Did you pass?whare are you now??

[@AXHM]

@@tofoo72 no we're going to figure this out, just keep checking every year

[@drummerreshma]

These videos are so helpful! Thanks!

[@MsAyoosh79]

Your videos on fluids saved my life. I wish you had videos on fluids with friction as well. Thank you so much :)

[@rachelle3572]

He is the only math/science teacher that i don't get annoyed by their voice. his voice is so nice!

[@luisrubio539]

these videos always help. they actually explain things well so you can understand it. not just tell you to memorize formulas

[@embevany]

I'm from Germany and trough you I understood so many complicated concepts picturally. Thank you for your effort, you are my favourite teacher on KZbin!

[@jnp4825]

this helps so much, thank you.

[@stephaniegreen4057]

@8:40 mind. blown. second time taking physics 1 and i have never seen this relationship.

[@bhavoh]

Ohh I saw about this guy on CNN Student News...thanks a lot for what you're doing! It's really inspiring and you make wayy more sense than my science teacher :D

[@musicaldarpan629]

10 year old 😳😅 amazing

[@caradelevingne9811]

Its too sad that KZbin has many easy examples but when my teacher asks a word problem that is hard, i can't find any solution to look for in youtube ☹️

[@sreeragsajilal6378]

how r u now ? u r in 10 th

[@BDMTV-lh3zf]

You are right

[@TheChamp91100]

Thats cuz these examples are basics to help u get going.. if u cant answer the "tough" questions.. u dont understand the basics...

[@nikolavideomaker]

I am at UNI and I am learning some quite complicated physics. These videos have helped me a lot. It is the basics that you must know before thinking of a problem. Imagine it like this you can not write a story if you do not know how to write.

[@abhijeetdate4190]

🤘🤘

[@ColRon]

This is a great review for my physics exam. thanks a lot

[@The_one_always_changing]

How did you do on your exam?

[@RandomVortex]

Anything that promotes learning is wonderful!

[@SamRobertduty]

I like your videos and It is answering all my questions. Thank you.

[@mansoralhammadi]

Adam Caith the comment is over 11 years 😱

[@gunter84]

I just want to let you know that I am taking Physics 1111 at the University of Georgia and I find your videos not only informative but VERY entertaining. Thanks!

[@amanicricket9367]

Michael Gunter hi there

[@musicaldarpan629]

Oldest comment here 😳👀

[@ordiv12345]

Thank you for sharing your knowledge.

[@ayfmlol9725]

This guy should be a millionare, he is so helpful and smart, Thank you!!!!!!!!!!!!!

[@alexander324324]

You are awesome dude! I was so desperate before i found your videos. Thank you very much.

[@larsalee]

my physics teacher is great, but this is a even better way of learning things!

[@gabbytangney9632]

This is the most helpful thing I have ever watched on KZbin!! Thank you so much!!

[@junng6848]

In physics, "work" is when a force applied to an object moves the object in the same direction as the force. If someone pushes against a wall, no work is done on the wall because it does not move. However, depressing a letter on a computer keyboard requires work.

[@shreyjha3206]

Work= Force*displacement

[@rollmosses1351]

Laughing Sküll workdone=force*displacementcostheta

[@ib3e]

@@rollmosses1351 r8

[@deeeoss21]

this guys the man. makes it so much easier

[@musicaldarpan629]

10 years ago 😳👀

[@yuliehe2002]

Love your caption So much! It completely solve my language problem

[@susanlin2377]

good way of learning things. this could help me 4 science homework!

[@nashaintsmol8385]

13 years ago... nice

[@RebornLegacy]

I always defined work as the transfer of energy onto another surface.

[@musicaldarpan629]

😃😃😃🤘🏻

[@academiarelatedemails9769]

Deriving (Vf^2*m)/2 from f*d blew my mind. Wow. Awesome video and I love your sense of humor!

[@helenkhudhur9178]

so useful 👍

[@yeetholmes619]

thank you 4 the good work sal...

[@syedrayyan9314]

Very thank you sir for delivering such a nice lecture .. helped me very mich .. cleared all my queries

[@aribanasir5289]

can u guys believe that this video was posted on 17-02-*2008* firkkin 13 years, many of us did not even reach this level of physics, stop reading the comments and pay attention lol

[@anonymouss910]

I have an exam physics tomorrow and I hope I don't fail after watching that video 🙏🙏🙏

[@uttamspl]

Tfd

[@dozza92]

thank you for that algebraic explenation to KE. Really helped :)

[@nimbhandari4272]

you are best than my teacher your way of teaching is really good

[@simsimsingh6]

yes it is! infact that connention helped me score pretty well on my physics paper!

[@meyouanushole]

@Guffington It can't be a bit confusing especially since most energy is related to the motion of particles. Thermal energy is related the motion of atoms. However radiant energy doesn't relate to particles in that way. In fact, the Large Hadron Collider (LHC) collides atoms and destroys them, when you destroy atoms you release pure energy...there is no particle left. In fact, sometimes weird things happen and particles are created from energy (so "out of thin air" by the way we would see it)

[@ballsoffury4]

C)No forces are doing work on the object D)There are no vertical forces acting on the object. Now if it is at a constant speed the net forces must equal zero and there is no acceleration. First off how does it move if something is pushing and pulling on it with the same force? Second, my book says there is work being done by pushing and going against (friction), how is there work being done if the net force is zero? Thanks and blessings :)

[@toofresh91]

KE should apply at any angle, because a force can move an object, with any angle to the horizontal. In this example, the vector F not moving at any angle, but parallel to the x-axis, so theta would be 0. Cos(0)=1. KE=(1/2)(mv^2)(1).

[@goodnothing4664]

Wooow man that's just what i needed. Healthier than a cup of coffee ;)

[@protoname_]

Thx so much!!! I have a physics midterm tomorrow!!!

[@pranjal527]

Sir, a little question i would like to get answered. Why were the concepts of Work and Energy developed ? Could you please provide me with some examples of scenarios where we can explain that scenario only with the help of Concept of 'Work and Energy'. A scenario which can exclusively be explained by the concept of 'Work and Energy' and no other concept of physics could explain it.

[@hgdeviant]

my mind exploded at 8:01. thank you sir for your sneaky awesome explanations.

[@narutosramenbuddy]

YOU SIR ARE AN ANGEL.

[@musicaldarpan629]

😆🤣 lmao

[@Anzalnaibrahim714]

thank u soo much for explaining this it was very informative

[@divyeshpk515]

Thanks u Sir.my dought got cleared after seeing the video .

[@algi6518]

Energy is what makes time and work possible. Work is an isolated event in which excess energy affects both the source of the abundant energy as well as the object that received some of the abundant energy

[@vishalasthana9269]

+Al Gi And do you believe most people would understand it? Much easier to write than speak sir.

[@algi6518]

I have an unreal imagination

[@misterman567]

very much liked the derivation of kinetic energy formula

[@lysafae]

GOT IT:P Could you give us some sample problems in which we can solve and then answering it after? I mean so that we could be more interactive.

[@EclipZeMuzik]

i really like this keep up the good work!

[@aliabdelmaboud312]

I am nothing but grateful ❤

[@julietnewton33]

Wow well understood OmG I read this tins so many time I'm just understanding it right nw thank God

[@shmiy8]

Which video explains the equation at 5:33?

[@humzaashraf321]

The future will be Khan Academy in every school

[@musicaldarpan629]

U lied bro... I am from future 😢

[@ashleysbigfans]

Kinda late now, but think of it as a fraction: f/m times d/1 (because d has always been in the numerator) so it becomes fd/m when multiplied

[@ram79la]

thanks so much !! very detailed and clear

[@dhruvchaudhary8054]

Are you still alive?

[@えみ-c3m]

Aww that cute small mistake he did at 4:22-4:25 :"> I love this tutorial! :))

[@Peter_1986]

"Whoops. ♫"

[@musicaldarpan629]

😃😃😃😃

[@princeagas9600]

when will you gonna use the angle theta?

[@musicaldarpan629]

😂😂😂😂😂😂lol

[@smitty16082]

what program do you use to do this?

[@bimboy08]

mannn ur going to help me alot im a senior taking physics and its confusing as hell but sad part is you use radicals or w/e u call them when you do cos

[@Guffington]

So, am I right and saying that energy doesn't actually "exist" in the same way that light and matter exist? It is just a model to help measure velocities and motion?

[@Peace-ey5hn]

I have a lot of ENERGY. But I just sit there on the couch. My parents come along and FORCE me to put that energy to WORK: I took out the garbage, mowed the lawn, and painted the porch.

[@shannonsamlal9945]

Thanks alot! You made it way easier for me :D SUBSCRIBED!

[@ADAEZEworship]

I love you!!! and your videos tooo!!!

[@musicaldarpan629]

😃😃😃

[@ashleysbigfans]

Does w = KE = (mv^2)/2 only when theta/the angle equals 0 so cos will be 1? Or does that KE equation apply for any angle?

[@sleepyxyz5]

I don't get the weirdo's who dislike his video.....Guess it proves that n matter how awesome u r u can't please everyone cause people have a tendency to be jealous idiots -.-

[@Melomathics]

Is F the *resultant* force on the object, or exactly the force 'needed' to move the object? e.g.: I might 'need' only 1 N to move an object over 1 metre, but if I apply a 10 N force to that object over 1 metre, am I still doing the same work as if I applied a 1 N over the same 1 metre distance?

[@sejalsingh3632]

V.nice sir

[@yoometh]

Thank you once again!

[@TheScienceCube]

Great!

[@teeannalleje7198]

I really love Khan, but Wikipedia isn't really a good source. Well, just sayin. Though, Khan is great! It really helps me a lot!

[@ushnamaqsood558]

Well understood

[@toofresh91]

@ Hamza Shihimy. Fg=Mass *Gravitation Acceleration. Ex 2kg*9.81m/s^2=19.62 N.

[@preciouskitten85]

thank you!

[@musicaldarpan629]

Oldest comment here 😳👀 What are you doing nowadays 😅

[@saumyaawasthi538]

Which software do you use????

[@runiali5583]

5:34, where can I find the video of proving this equation

[@pancakesareforme]

14 people couldn't understand how great khanacademy is...

[@musicaldarpan629]

Now 300 😃😅

[@stephenpogi998]

this is great!

[@junng6848]

Is typing on a computer keyboard consider doing work in physics sense?

[@samuel9skinner]

+Jun Ng you are using energy so technically yes but not really

[@obeidatmd]

+Ahmar khan Nope, you're displacing the keyboard buttons from their orginal position.

[@callumissocoollikf]

+Ahmar khan yes it is, you're applying force to something in order to move it, every form of movement is work done.

[@tabaicanking3701]

movement and force. since work=force * distance

[@perihangummadova5017]

as i understand, both the keyborad and you finger are doing work. we all know that the keyboard is doing work. but, in the light of our fingers applying force to pess the button and the movement of our finger (up to down),we are doing work.

[@ballsoffury4]

Hi Khan or anyone who can help I'm very annoyed right now I seemed to understand Physics very well when I took the course but am having a little trouble as I am studying for the Mcat. Anyways I have this question An object with a mass of 50 kg moves across a level surface with a constant speed of 15m/s. Kinetic friction=.7 which of the following is true. A)The force exerted on the object by kinetic friction is negligible. B) There must be some other horizontal force acting on the object.

[@MrSidney9]

Work is energy in transfer. For a definition less circular

[@alisuri6637]

Nobody: Literraly nobody: Khan: I just found this from Wikipedia :)

[@monissuri6803]

I know

[@monissuri6803]

Haha

[@monissuri6803]

Stupaad

[@alisuri6637]

@@monissuri6803 heh

[@Purple9471]

Run right through him with your arm forward with fist. Power and Force are as fast as you run. 0 to 1 to 2 to 3 to 4 to 5 to 6 to 7 to 8 miles per hour (so x times). So the faster you run the more power and force you have. Go Girls!

[@karkourkhawla9808]

thank you so much for thes informations thanks a lot

[@sayandas9744]

isn't work = force * displacement instead of force * distance ?

[@vsmoonchildmahir283]

Nah, work is the distance moved in the direction of force *not* displacement, because displacement is the net distance moved

[@kayseil]

which app do you use to explain everything?!!

[@1ThatSkater]

what would i do if there is weight involved in the problem thanks

[@SmogHouseTradingCo]

You go from v"square"= 2 f/m d - then go to v = square root of 2 fd/m, how did it go from f/md to fd/m?

[@chinmaygupta1530]

*Why is this video 240p? I know that this is just a first world problem, but aren't the videos usually 720p?*

[@sumanrai1422]

The Real EEED Cure is over 300 Yеars Old! twitter.com/aa553651fdb95b460/status/804602507225808896 Introduction to work and energy Work and energy Physics Khan Acaaaademy