Introduction to Momentum

[midgetMouze]

I think impulse is just (triangle)P

[SkyWaveFilms]

Now I like physics, you won a subscriber :)

[HaiImClarakins]

Thank you so much! This was so helpful :)

[shamiiix33]

impulse is J. and you showed us an inelastic collision with the car and truck. Thank you :)

[Kricardose]

I am very happy to see the What momentum is. A simple problem involving momentum.after you give this

[bebeheuy]

I Love The Video What momentum is. A simple problem involving momentum It Can Increase My Knowledge

[Mjhond]

Steady I Really Like This Video What momentum is. A simple problem involving momentum

[MrPEDOCTOR]

its a logic dude.

[SuperXD25]

6:20 too bad the truck was stationary... otherwise the momentum would've been OVER 9000!!!!!

[Zumerjud]

the unit of impulse is the Newton second which is not equivalent to the joule

[checkyesmari]

while i'm watching this video I just can think: your voice sounds like John Mayer hahaha

[raptorclaw333]

im having a problem with the equation d=vt i know the distance but i dont know the velocity and the time i tried to work out the velocity by doing v=at , say a= gravity 9.8m/s2 but i dont know the time so i cant work it out could someone help me

[estejabon]

@raptorclaw333

i'm assuming your doing a free fall problem? If so you can find time by getting the square root of the height at which it falls from times 2 and then devide it all by g so in a formula it would look like squareroot of 2h/g

hope that helped

[estejabon]

@raptorclaw333 the original formula is x (or y) =1/2gt^2

[beadgirl97]

Impulse is not measured in joules..

[hahs4]

how unpleasant would it be to hit by that object. LOL

[tomarunamerienda]

my physics c teacher relies completely on us self-studying because he barely knows the material himself. so THANK YOU!!

[4thKyuubi]

@tomarunamerienda lmao

[FindingVickie]

@miniradman I hope you're not suggesting that my physics class is, in ANY way, easy. I have to stay up past midnight EVERY NIGHT working on physics.

Also, I just heard that my physics class is being turned into an AP Physics class. We do enough work for it!

[FindingVickie]

@sweetgirl94949 I am also in grade 11 physics, and my class is just starting to learn this.

Point: You will most likely see this soon.

[miniradman]

@FindingVickie I'm also in year 11 physics and my class is already pass the simple stuff, now we're going onto the tough stuff :s

[sweetgirl94949]

thanks Salman!

[JediOfTheSea23]

Sal is such a boss.

[TheEvilEmporerBunny]

What does the scouter say about the momentum level?

It's over NINEEEEEEEEEE THOUSAAAAAAAAAAAAND

[MrNeonmaniac]

I am ur huge fan ! Physics has actually started attracting me becoz of u !

[MrVverila]

Im taking this in 9th grade.

[estejabon]

@MrVverila just curious, are you taking pr physics or regular? since i took pr 9th and now (11th) i'm in ap physics

[JiMmOo0]

In what grade do you guys take this ?

[sweetgirl94949]

@JiMmOo0 im in grade 11 physics and this is the first time im learning this

[SoapBoxDancer]

don't you loose momentum because you loose velocity in the end..

[MrNeonmaniac]

@SoapBoxDancer the mass of the new object(cartruck as named) is equal to 3000kg that is the combined mass of both the objects and since momentum is the product of mass and velocity so its not decreased( although velocity is being decreased but the mass has increased)

[mihirt97]

A VERY HELPFUL VID!!

[sweetylova7]

thank you so much -- you're the only person on the web who can explain momentum in a short but understandable way

[thechildrenzplace]

..not gonna lie but you make me waNNA learn.

[riashadbro]

i have my yearlies next week, and i gave up on physics after half yearlies, but not started to study it agian but couldnt understand momentum and impulse

HOWEVER

NOW

I DO

:D

thanks khan !

[SpeedAbsolution]

OK PROS PLZ HELP ME IM REALLY STUCK ON THIS ONE:

I try do solve this problem using the kinectic energy equation: E = 1/2*mv^2.

So the energy of the car is 40500J. And when the car hits the truck, the energy will still be 40500J, but the mass increased to 3000kg. Now let's solve the equation and I got v=5.2m/s!!! not 3m/s..

O_O help plz..

[Jazalibur]

My teacher just reads off power points and text books .... Hard to understand things in year 11 

[000watchingyou000]

Sir, i don't understand why we need to add the two masses ( here : the truck and the car) before they collide, cause momentum is conserved only after they collide.

[ansarinazim1]

Delta P = J

[daksh96]

How can we do this problem using force?

[kodexz5]

I wish more people were like Sal, who would care about other people so much, i.e. investing his own precious time in making these EXTREMELY useful free videos. So let's not be selfish and thank Sal by donating whatever we can, no matter how small or big it is! Thumbs up if you agree

[MrParham00]

You're a science gift from the gods of science. Damn i love your videos.

[enzorussian]

1000kg is exactly one ton not slightly over

[TheLost4rmzone]

Oh... my... god... I FINALLY UNDERSTAND WHY MOMENTUM IS CONSERVED. Thank-you so much. Your videos are so helpful. I watch them on my free time... that's sorta surprising.

[MrKallebra]

pinkyfrompk- definetly P

J is joules or energy units

[JohnIsMoreThanU]

Khan Academy has saved my grades more than once and this physics video only has 75,000 views?! More people have to learn of this site!!!

[MrViele83]

thumbs ip if you came because of portal

[TheOxygenstatic]

j stands for joule, and impulse is "I" and i think its unit is N,s or Kgm/s2 * s

[pidde15]

"a 1000 kg... so a little over a ton!" nopee 1 ton = 1000 kg !! hahah ;) but you'r entertaining and have a sympathic voice (no homo) plus you can explain it well so thanks buddy!!

[shartle94]

@pidde15 Actually, a ton is 2000 US pounds, or 909 metric kg, so he was correct in his statement.

[pidde15]

@shartle94 Oh, I'm from europe so i never even heard about metric kg. Thanks man. 

[metalmaniac767]

@shartle94 One "Short Ton" is 909 metric kg. One "Metric Ton" is 1000kg.

[VegetableFRIES]

Thanks for the help, this video really helped me a lot. My physics teacher is great, but explaining a problem and whatnot slows her down, yet you must be very quick to catch it and have good intuition to fathom it. Ironically, I had this same exact question on a test, and though I've presented an invalid answer, I'm glad to have finally understood this formula. I used to think it, (m1)(v1)=(m1)(m2), even with the knowledge of the formula you've shown. I was a bit doubtful...

:/

[kilmurraygirl6193]

Thanks so much for this video. I have a great physics teacher but he often explains things very, very quickly. This helps so much with my homework. The way you explain things makes so much more sense. 

[ThoughtGazeCarlos]

When thinking of momentum think about the character Juggernaut from the X-Men movie. Wouldn't like to get hit by him.

[thebigblu13]

I believe that a car-truck is called an "El Camino" :P

[gengen23100]

THANK YOU SO MUCH! YOU ARE AMAZING!

[ishotyaaa]

lmao.. a cartruck!

[seppy50]

THANKS! SUBSCRIBED :)

[darkcornbreadhunter]

hmm, I saw a cartruck on my way to class today!

[donchng1994]

u shld come and tutor me for my ib physics higher level

[BeeezyFBaby23]

P because Plura Means Momenta , So Momentum (:

[Yvesiscool]

Does the problem with the car and truck happen in a frictionless plane?



[IIIDeathWraithIII]

@Yvesiscool ofc :/

[crimsonxXxeagle666]

you just got another subscriber :)

[aznlily124]

Thanks for everything that your doing. I was wondering if you can do a video on Elastic and Inelastic Collisions for physics? For momentum. Thank you so much :D

[AbbasBagwala]

Thank you Khan.. (if that's your name :D ) 

[jlspma]

Lots of help thanks!

[tnagan]

Sal, thank you so much. I've been a student of yours for over a year, and you have helped me immensely. 

[ckabhinav]

Explanations were comprehensive.....

[lsass911]

Thank you very much ,, u really helped me

[dalcde]

Those cars are really slow...

[EatShanklish]

M1=1000 kg

M2=2000kg

Initial Velocity.= 9 m/s

Initial Velocity 2= 0

Final Velocity=Vf

We pretty much need the Final Velocity, and since they both the smaller car embeds itself in the truck, theyre going to have the same final velocity. So,

*M1xVi + M2xVi2= M1xVf + M2xVf, *The Formula.

1000x9 +2000x0 = 1000Vf + 2000Vf

9000= 3000Vf

Vf= 9000/3000 which leaves us with Vf= 3 m/s

[sandygill619]

wow this was really helpful : |

[yyttr4]

[;\frac{3}{4};]

[yyttr4]

Yea... [;\nabla(v);]

[SentientRaven]

Kilogram-meters per second, eh?

[thevadercrucible]

"J" is used for impulse in my textbook

[edwebo]

a car with a magenta bottom..

XD

[wildrider100]

u shud open up a skool



[StephenMcCrystall]

Thank you! I find physics enjoyable and generally easy, but somehow, I've managed to not understand momentum. As we are really under pressure to get our course finished on time, I've fallen behind on momentum. So thanks for explaining it in great detail xD

[randumbtimes3]

N*s =/= Joule

N*m = Joule...

[thegamefox1]

you are amazing!@!!!!!! I understood what you were saying right away. Im not trying to be mean to my teacher in any way, but your teaching methods are far better. Thank you so much Khan!!!!!!!!!! BTW how do you write so well on your computer?

[D0g63rt]

What 9000?

[hallieberrygoodup]

i love u keep doing the good work don't let anyone discourage u from teaching i understand every work u stay thanks

[94jmcorrea]

Thank you from Colombia! you are the physics teacher I have never had the patience to listen to

[MrPlender]

Why is it that momentum is always conserved?

[Tedjevanes4001]

very nice man, you've made things pretty clear to me, keep it up!

[drstingrae]

Another analogy for impulse, would be the Cardiac Defribrillator, that actually send a force of 300-360 Joules to restart the heart.

Just another idea, o fully understand things, as useful tools!

THESE ARE REALLY GOOD REVIEWS THOUGH!

[drstingrae]

Kaplan give an example of a Ship and a Bullet..

That starts it off much better.

Just an idea for you!

[Deflorescere]

This is great [:

[PeeteeyL]

life saver

[paulojunior201]

lets run really fast and im a big guy

[a9933]

nice example !

[archis84]

I am confused. In my language we call impulss p=mv. I always wondered why americans call it momentum. What's wrong here? lv(dot)wikipedia (dot)org/wiki/Impulss

[himearieru77]

haha CarTruck nyc 1...

[jmkupka]

Unbelievable! Just started physics, can't stop watching these vids, nodding yes, yes to my teacher (cuz all is so clear thanx to these vids), wife sez I'm such a loser. You've taught me 4yrs of math in the last 3 months. You're going to heaven, or valhalla, or wherever!

[HabibSardar]

Thanks you!! Keep posting:)

[serchyissexy]

he's indian, riggparkstephen

[whatthewonderfulland]

YOU DID WELL!!

[DSmusicguy]

wow. i love you.

Now I will not fail! haha!

[riggparkstephen]

can someone answer me is this guy black or white, no racist please reply

[Dundertaker]

@riggparkstephen

He's Brown

[reece0krazy]

omg. thanx alot. u make it so easy. gd job!!!

[erkannnaga]

He speaks like he is eating a quince.lol

But he is a good lecturer.

[sabriel80]

Just to clear some things up for the viewers...

The symbol that represents impulse is J and the unit is N•sec

The symbol that represents energy is E and the unit is J (joules)

[michalchik]

Yep. that is what i meant to say.

[michalchik]

~3:30 you say, the unit of momentum is joules. That is the unit of energy. P=KgM/s^2, E = KgM^2/S^2

[siinghdj]

@michalchik

He says impulse, not momentum, which is correct.

[MrGMauler]

how is his voice sexy??? lol

[MrGMauler]

thx

[lilmannorcross54]

dog, your voice is sexy, i cant help it

[PinkyFromPK]

I believe they use letter "J" for impulse.

[mouli106]

@PinkyFromPK They use I for momentum!

[purplezeke]

@PinkyFromPK Not at all, it's "P".

[pidde15]

@PinkyFromPK i believe the letter J stands for joule and is a unit

i think thats what it is lol sorry if you meant that

[vahmcatvz]

@pidde15 j is the letter for impulse and J is the unit for work and energy

[Drizzen123]

@PinkyFromPK`No, "I"

[vahmcatvz]

@Drizzen123 its j

[sharkfeet123]

@PinkyFromPK ur just being selfish

[ardiweezybaby]

THANK YOU!!!!

[whitefroufrou]

I am going to pass my test next week because of this. :] Haha.

[simsimsingh6]

Hi! Loved the video! I was just wondering what kind of a child you were! Were you always solving problems for others????

[BPColin]

1:11 - 1:22 LOL

[pirocan1]

wat a sexy ass voice

[Ihatenicknames1]

very good video =D=D!!

thank you ^_^

[HammamTube]

I want thank you

it is great vedio

[checkeraka47]

What about angular and linear momentum?

[calvinhobbesliker2]

The kinetic energy of the car is 40,500 J, and the kinetic energy of the car-truck is 13,500 J. Assuming to loss to heat or sound, where did the energy go?

[ridleychris0329]

how did you get KE=13,500 J with v=0m/s?

[calvinhobbesliker2]

v=3 m/s. I was talking about the final system.

[PinkyFromPK]

tell me how would YOU ???

[brent826]

Okay thanks, my physics teacher always uses the arrow and I never see it anywheres else so I was a bit confused

[AceStapler]

brent, you are partially correct however, Work uses the units Joules, but it is a (J) without an arrow over it. This is also the units for Kinetic Energy and Potential energy.

[bEmusEdpAnDa]

whoa amazing

[shaan8426]

i think it's great. thanx.

[AceStapler]

impulse is J (with an arrow over it)

[brent826]

Isn't the J(with an arrow over it) work, measured in Jules

[AceStapler]

As far as I know units never have the arrow over them. In this case it is vector notation. Impulse can either be viewed as a vector quantity (a number with a direction) or simply as the magnitude of impulse (purely a number). For anyone reading this who doesn't understand vector notation: Vector notation is any variable with an arrow above it. This arrow means that we have a quantity (magnitude) of something with a direction(angle or components-components being in R1-x, R2-x,y , R3-x,y,z....)

[aaamandii]

aaaah thank you so so much :) i have a gcse exam soon and you have no idea how much of a confidence boost you have given me.

[jennyuzzy]

this is really gr8. am glad i found it. thanks

[irgopwn]

UURRRR a legend m8, i passed my physics exam. Ur way betta then my fukin teacher ur a legend LLLOOOVEE u LOL

[Zephyruu]

Fuck year, Cartruck!

[demonheart1514]

lol... symbol of impulse is J dont ask me why though :P

[demonheart1514]

and the unit is the N.s

[pookellypoo]

Cartruck, lmfao. Man its awesome watching your videos

[jimy5527966]

the equation for impulse is equal to the objects change in momentum which is Ft=P, i think that this would help u at 3:00 and this is a really gud video keep up the gud work

best wishes

[psychox4]

you make it so clear, you're great. thank you!

[personsame]

WHERE can i get more vides?

[CoreaFever]

u helped me more than my college professor...

Thank YOU!!

[darkknight302]

@CoreaFever they teach this in college?

[HjalmarGuitarMaster]

@CoreaFever I agree totaly!

[DeathByLight]

Best tutor in the world

[Xanimal1221]

very nice, good job