First law of thermodynamics- Never talk about thermodynamics.

@coimbralaw

Жыл бұрын

👎🏻

@iAnesxx

3 ай бұрын

is that a ******* ****** reference ?

@janakm4135

24 күн бұрын

@@iAnesxxdefinitely 😂

He really understands the value of intuition when teaching hard to grasp concepts, that's why his material is the best. Cheers.

U for internal energy. The way I remember that is internal does not start with a U.

@kdogallyall

8 жыл бұрын

+eragon2121 I read this before I got to it in the video and was so confused

@blackswan9645

6 жыл бұрын

eragon2121 sodium starts with S but its NA in chemistry

@red_isopat

6 жыл бұрын

Black Swan its natrium in most languages

@dhruvverma6938

6 жыл бұрын

Neither does initial velocity start with u.

@rajibhalder1991

4 жыл бұрын

You are wrong, it's unternal energy.

That Is like the first law of everything.

@urairaktaifoi2190

7 жыл бұрын

Raj Harsh คััา

@munirasuappavu6437

5 жыл бұрын

worse

I cannot thank you more! You are simply amazing. A gift to the people who are eager to learn!

I've been watching these videos for close to 4 years now. I love how you can tell the age of his videos by the resolution of the writing. The newer ones are so much more crisp.

@wings4994

3 жыл бұрын

And your comment was made 6 years ago..

@kendo512

3 жыл бұрын

@@wings4994 thanks for the flash back

@kendo512

2 жыл бұрын

@just some guy tired of life my friend I’ve had this KZread account since 2007

8:00 internal energy

Khan, you're the best! Literally life saver for my exam in 3 days.

@ivarbaratheon264

6 жыл бұрын

My exam in 2 days lol

@geico105

5 жыл бұрын

My exam is tomorrow lol

@RahulSharma-hk5yk

5 жыл бұрын

My exam passed LoL.

@ralphlaurenebol2835

4 жыл бұрын

My exam is today

@carlobadiola4994

4 жыл бұрын

My exam is an hour away

Dude you are some of the best professors out there you make mine look like a disappointment.

@anuradhikabajaj9585

4 жыл бұрын

@ aniswar lax 🤣🤣

This is so amazing...I cannot thank you enough KhanAcademy for all the helpful tutorials...It has expanded my knowledge in Chemistry and reduced my worries :) Thank You.

My favorite part: "U for internal energy... The way I remember this is because 'Internal' does not begin with 'U' " lol

Thank you so much! Extremely helpful 👌🏻

When you realize, that you spent hours surfing the internet looking for this stuff explained, and they were here ALL THE TIME. Great courses.

Awesome, good practice for remembering for a ME graduated some years ago!!!

This is making alot of sense thanks you sal for your spend tim to save me from headaches at night😊

You are really AWESOME! thanks for being such a great help!!

Khan post too many videos. Coolest people ever

thanks for this vid! it's really help me in the exams!

The first part is law of Conservation of Energy...... Thermodynamics is about Heat in closed system. ΔU = Q - W could u pls tell more about the heat and adiabatic process.

@ashasalelkar7457

6 жыл бұрын

Adiabatic process is one where heat is neither transfered into or out of the system. Hence Q will be 0. Therefore W will be equal to -U. Now this is equal to -nCv(Ti-Tf). Cv is the specific heat at constant volume (Note - Cv is not only used for isochoric processes as it is thought to be by many. That is a mistake. Cv can be used for adiabatic and isothermal as well) . Now after substituting the expression for Cv. The FINAL eqn for W will be (PiVi-PfVf)/(gamma) - 1. So this just means that if work is done by a gas is positive, volume of the gas will increase and U will be more negative.

This is Amazing

I also liked this one..and also apreciate the person who upload these kind of helpful videos... carry on... God Bless you!!

this is a very interesting video and very informative!

does this guy just know everything. no matter what class im struggling with, he's got something up his sleeve lol

wow this was so easy to understand. If only one of my teachers came close to this.

this is the coolest video i have ever seen....I love Khan Academy

Well i rather waste my time watching him write than to sit at lecture class staring at the ppt slides that confuse me. He's taking his time to help us students understand things that are unclear to us. Your comment was unnecessary and rude...

thank you for this interesting video

@hybeerian I am a philosophy teacher in a school, and did this so my students could reply to your comment (we have been studying Ryle's 'myth of volitions'). You ask "can the energies of yore [sic] internal self exist in another form such as 'ghost' or spirit?" They have answered that question for you: that there is no such thing as an 'internal self' such as states of mind, they are in fact just ways of behaving, and thus physical like the 'carbon moleicles [sic]' that you recognise exist.

I understand you better than my lecturer.. thanks so much khan academy

Thanks, Very good video and good refresher.....

@hybeerian While there may be many different ways to store or to release energy, energy itself is equivalent. The reason that static electricity doesn't kill you is that there isn't enough current (amount of charge passing a given point at any one second) while in an Alternating Current or Direct Current Circuit there can be if there is not enough resistance. This does not mean that the energy itself is any different though. You can also essentially break down all forms of energy into...

wow. Its week tw and im still confused but now i understand. Thanks very much

wow physics on chemistry! this helps since Im takng physics 1 with chem 2.

Thank you khan, you are the man!

Be grateful that someone is willing to spend their time teaching you

Very well explained!!

Khan this is very useful ......

It can absolutely be applied to digestion. Calories are a unit of measure for heat. By determining the caloric intake, taking into account the efficiency of the human body in processing those calories, you can determine, fairly accurately, how much work the body would need to perform in order to "burn" the calories ingested.

from where kinetic comes from ?although the participial is at ground state the is no motion. kinetic energy is due to the motion of particles /mass??

took that straight out of my head dude haha

@ChirtyPoundsOfBoost Thanks! So the air resistance when the ball is being thrown upwards is much smaller than AR when the ball is moving back to the ground? Therefore, it's not "worth" mentioning the upward resistance?

this was really helpful

very very good guide, your not boring at all

Love you sal Khan! You are the best teacher I ever had!

great video....thank you so much god bless u.

dude you're amazing i love this!

Wouldn't throwing the ball up meet the same amount of air resistance as it would when falling? Thus making the speed of the ball the same both ways?

Whats the difference between work done and pressure volume work?

So in the case flash paper, if one burns the paper it just disappear . So what has been done to the energy not destroyed????

Perfect!

very clear , well done

Thanks .But I have a question.Are we serving as a system or as a surrounding ?

@bleedinmagnification it radiates out into the surroundings, doing work to speed up other molecules, perhaps the molecules in the walls of the container...

Thankyou so much sir you are just amazing.

Seriously, I wish my professor is like Sal. My professor is seriously terrible at explaining everything; I think he does not understand how a student learns.. Thanks Khan Academy.

Khan Academy helped me so much in my development

@hybeerian Thanks for your reply. Technically matter and energy are different forms of the same thing, but essentially I see your point. However, I would not so readily classify everything as either of those. Information fits into a category I like to call patterns, which our brains love to identify. For example, if you were to print this page out, there would be information on it. Now you could add up the energy in the ink of the text, but I would not say that this energy "is" the information.

Does the First Law of Thermodynamics apply to cold and heat energy or does it extend into types of energy like electricity (or even bio-electric -neurons) for example? If anyone can help me with this curiosity please send me a reply. Thank you.

So it was said that atoms don't really have rotational energy but molecules potentially do bc of sigma bonds that are able to rotate. However, atoms have atomic spin. Doesn't that translate into rotational energy? Was this an accidental omission or do atoms also have rotational energy? Much gratitude for your videos!

thank you!

very very usefull , good work , and you are very pro :)

You're better than my physics lecturers ANY day

thanks for uploading!!! YOU ARE THE BEST!!!!

"no Mr first law of thermodynamics '' this should be a line in a Neil Gaiman book

Good question. The law of conservation of energy is precisely why perpetual motion is "impossible". For motion to be perpetual, there would need to be no negative forces acting on the object in motion. As he discusses in the video, friction is one of these negative forces. So, since the law of conservation of energy states that energy cannot be destroyed, it has to go somewhere, right? Well, in the case of friction, the energy is converted from kinetic energy to heat.

Thank you for this video,it help me a lot.Greetengs from Serbia

I think Sal's favorite word is "intuitive" ;)

7:32 KE was transferred to air particles (rub) = heat 11:49, 12:44 internal energy (U) - "all the energy that is in a system"

hi khan academy does it mean in a thermodynamic cycle change in internal energy is zero

Right after watching this i went outside and threw a rock in the air XD

Incredibly helpfull

Best explanation ❤!

Difference in velocity might be one of the reasons for less Kinetic Energy.

It’s always U = Q + W . The sign conventions of W differs depends whether ur class is chemistry, physics, or engineering.

very few teachers uses this concrete method,,, talented

'And then I say no, Mister first law of Thermodynamics' XD 'The way I remember U stands for internal energy? Internal Energy doesn't start with a U!' Hahaha your funny comments in the vids help me to remember the content so much better !

@hybeerian Thanks for your reply. My argument is essentially that the information in our brains is not energy. It is the result of patterns in our neural network. I will also stress that there is no such thing as one kind of energy or another kind of energy. All energy is equivalent. The energy inside my computer is exactly the same as the energy inside my head. The only difference is in the arrangement of that energy.

wait i have a question wen a gas is released from a container into a room dose it expand?

Vary super cool & good topics

i have question: A glass cleaned in 45celcius hot water and placed on the table bottom up. The room air at 20 celcius that was trapped in theglass gets heated up to 40 celcius and some of it leaks out so the net resulting pressure inside is 2 kPa above ambient pressure of 101kPa. Now the glass and the air inside cools down to room temperature. what is the pressure inside the glass?

very helpful

Thank you so much

Calculate AU for an endorthemic process in wc 20.6kj flows and where 13.7kj is done on the system

What factors affect the internal energy of water and steam. Please help thank you.

@ivarbaratheon264

6 жыл бұрын

It's temperature

WHY do we have to learn this in med school...hate my prof lmao. Ty buddy

Gracias.

Thanks!

What is kinetic energy measured in?

Yea. You can watch the videos at 2x the speed like I do! :D It saves so much time when I am watching lectures or learning things on youtube!

excellent explanation...i could have learned from KZread a long way before....anyways i'm happy i see it now !!:-)

@kroflet No the air resistance is the same, the density of air in this frame of reference is the same.

@MerkaMage check out Heisenberg uncertainty principle when it comes to quantum mechanics.

Don't you have air resistance throwing the ball up into the air as well (as it falling downward)? Can someone explain to me why there is more kinetic energy when the ball is thrown upwards than when it is falling downward? I would have thought because there is nothing opposing gravity's negative acceleration then the kinetic energy would be greater. Though you say there IS opposition and that it is air resistance, I wonder why you say there isn't any as the ball is thrown upward..

@Sinnbad21

6 жыл бұрын

Chris Guillen I know I’m a little late. Sorry. And I think your I understood your question. There is air resistance and friction whether you are throwing the ball up or down. Rocket Ships leaving the ground get very very hot when going up through the air because they are encountering air resistance. Same for coming down. That’s why meteors are on fire when they enter the earths atmosphere. The reason the ball slows when going up is also because of gravity. Anything launched in the air will ALWAYS come back down due to gravity unless it is going at a speed of 7 miles per second or more (that’s the speed you need to beat the gravity force holding you down). The ball when coming back down will speed up bcuz of gravity until it reaches a certain speed where it can’t go any faster because of air resistance. This is called terminal velocity. If you jump out of plane you will fall faster and faster until you reach terminal velocity (which I think is somewhere around 120 mph. I can’t entirely remember). The reason there is more energy when being thrown up than when it comes back down is because he has thrown it harder and faster than the speed it would naturally fall down at with just gravity pulling it. If I was floating in the air above him and he threw the ball to me at 10mph and I catch it. And then I throw it back down at the ground 15mph then it has more kinetic energy going down because of the force or work I put into it. I guess it just depends on high you throw the ball also. If I throw it one inch in the air from my hand that means there was barely any kinetic energy put into it and it will surely fall faster and have more energy when it fell to the ground than it did when I threw it up an inch. Me throwing it into the air one inch means it only went like 1 or 2 mph (I’m guessing) but when it falls back down to the ground because of gravity it will have to travel a few feet and within that time it will gain more energy than it had when I threw it a measly one inch in the air. Hope that makes sense. In short it he threw it with more force going up than the force of gravity pulling down

@zodial I am just wondering the same thing. got any good answers? :)

@kroflet There is, the ball is trasnferring its kinetic energy into thermal energy when its traveling against gravity as well. He made it seem like the force that accelerated the ball upwards was much greater then when the force of gravity acceled it downwards.

Love you khan academy

So of energy can't be created or destroyed. How is it possible that subatomic particals can be created in a vacuum, even though it is for a milisecond or less?

Where did the remaining kinetic energy go after the ball hit the ground?

@VankyKataria

6 жыл бұрын

andrew hastings As the ball hits the ground,Due to a imperfect elastic collision of the ground and the ball,Some amount of energy of the ball is absorbed by the ground,And the remaining is used to make the ball bounce again(But,This time the total kinetic energy of the ball has decreased)..This keeps on going unless the Total Kinetic energy of the ball becomes zero

I have a question. Why do you use the capital delta in U = q + w, where q = -w ? Doesn't q and w depend on how you got them? And therefore they aren't situational functions, but path functions? I don't know how you call these functions in english though. In Dutch they're called 'baanfuncties' and 'toestandsfuncties'

what app or program do they use for these videos?

@AlexG-mj3bv

7 жыл бұрын

Im not sure, look on the website