This is a trip down memory lane. Back in 2014, I was all over this channel. Now, I'm a full time project engineer, about two years deep, and this content feels like muscle memory. Thanks for all you do. You certainly helped me out along the way man times.
Most of the time, my teacher just throws the material for us to learn and doesn't explain anything in depth. So after awhile, we tend to forget a lot of information due to the fact that we don't actually understand anything but memorize the information. It's videos like these that help so much.
The problem statement regards a US car, where power and acceleration is measured in horsepower and miles per hour. This was a deliberate choice to NOT use SI based on the context.
Holy crap I commented this a year ago. I’m now in 9th and still don’t quite understand it. Your comment motivated me to restudy physics and chemistry. So thanks for that lol.
We can accelerate in circle. Infact any circular motion is accelerated motion because direction of velocity changes at each point of the circular path. And change is velocity is defined as acceleration. So we can accelerate in circles.
When something is travelling in a circle there's always an acceleration. Its called centripetal acceleration and the formula is (Ac=(v^2)/r) Ac being acceleration and r being the radius of the circle
Thank you for this. Your tutorials are useful especially in this time of pandemic where we go to school through online class which is hard to deal with but you're here, teaching us. Thanks a lot. God bless
For those of you who still don't get it: 20 mph/sec means that for every second the car is increasing it's speed by 20mph.ie,At the first second(t=1) it's speed is 20mph,the 2nd second(t=2) it's speed is 40mph(20+20),the 3rd second it's speed is 60mph(20+20+20) and so on-mph per second.
Shout to khan academy. Khan academy teaches us a lot. Who supports me? Give like and who does not give unlike. My teacher says Read and disappear . Before ending the class period he comes back and gives us another lesson
The direction of an accelerating car is forward. It can't travel directly left or right - up or down, just forward and backward. Reverse acceleration is of little interest, and forward is the direction a car is geared to accelerate the most effectively. The direction inferred by a cars acceleration statistics is forward. Or as the notation you brought = 20mph/sec (+). Where reverse would be (-) and null = 0 mph/sec.
You are right that the car is ALWAYS going forward. Negative acceleration would not be in the reverse direction. It would simple be Deceleration in the forward direction.
Thanks for the help 😭 My science teacher doesn’t make sense and I don’t understand anything until I searched how to solve acceleration. Your video saved me at the last minute because I’m literally up at 2 in the morning studying for a science quiz ;-;
I am from India, I see Khan giving free ad for the brand Porsche. With khan academy growing day by day using brand names becomes free ad for those products or services. I think he should consider getting sponsorship from them before using it in his videos, this video has more than 10000 views. They can pay per view and help Free education or change the education system around the world.
I find it much easier to simply convert 60 miles per hour in meters per hour, using a calculator of course (except if someone doesn't need). So 60 mi/h is equal to 26,816 m/s. We divide 26,816 by 3 and we get 8,9 m/s2. 8,9 is indeed 1/180th of a mile, so we got the same result. Also I think that Europeans like me would probably like this method much more, we aren't really familiar with miles.
Excellent explanation. "Per second, per second" makes sense to me now!! I was trying learn the equation E=mc2 and wanted to know what is c-square and I ran into your video. Thank you so much KA !!!
I never understood seconds per second or seconds squared until I watched this video. I just couldn't picture it. Thanks so much. I'll be watching a lot more of your video's.
First of all, ı am Turkish and ı did not understand this issue. thanks to the translation and thanks to you in a very nice way ı’ll follow you now and ı’ll learn again thanks you.(sorry the translation may be wrong)
+YaSaman HF it is because m/s is velocity. and acceleration is m/s÷time. We denote time here as s=seconds or s/1. Acceleration =m/s÷s/1 =m/s×1/s Here both 's' will be in the denominator. When we multiply those two 's' you get s^2. Hence m/s^2 I am 13 so don't get mad if I did not explain clearly. It would be better to understand it if you wrote it down in a paper... That's what physicists do...
@tIs4gatorbait What exactly do you mean? The Earth's acceleration is on average always 9.8 m/s^2. An object does speed up in velocity over time with acceleration applied but that does not mean acceleration itself is speeding up. For example, an apple dropped to the ground would be moving at 9.8 m/s in 1 second, 19.6 m/s in 2 seconds, etc.
Hey,I have a question- a problem solving question.Well,here goes... A 72 N force accelerates mass m1 by 5.0m/s2.The same force acts on another mass m2 and imparts to it an acceleration of 20.0m/s2.What acceleration will the same force impart to the two masses when they joined together? Answer it pls cause I REALLY need the answer...
The video is 9:05 long and half of it is you showing us ways of writing the answer 😂 Let me tell you the problem isn't there, it's how to get the answer that most of us is here for.
@maveric2170 yes.. it will be much easier if u convert at the start. if question is given in hours or mins. its always better to convert to SI unit.. unless u are asked to give the answer in km/h or so.
Squared second?! What is the second? Move of Earth in equator of 460 meters (per second)? Or on poles close to zero meters? Or heart beat of passing life? Or relation between those two? What is the time? How time can be squared? Some basic terms has to be defined, starting from time.
This is a trip down memory lane. Back in 2014, I was all over this channel. Now, I'm a full time project engineer, about two years deep, and this content feels like muscle memory. Thanks for all you do. You certainly helped me out along the way man times.
Nice
congrats
I learned nothing from a 1hr class but this a 9min video helped me pass my test
I got "A" on my physics report!! Thank you so much for your awesome explanation^o^
nice
Good job bro
Shout to Khan Academy bc my teacher definitely doesn't teach me anything :))))))
+Katie Reynolds same :(((
shout out to the most real comment ever read.
wow
Katie Reynolds OMG same
SAMMMEEE
I love how when sal says a word, he first says it, then writes it down, and then, while writing it down, slowly sounds out the word!
boi
Me too
His voice is understandable
i actually like everything about him except for that, its a bit annoying
this man teaches better than my AP physics, and all my teachers gives us a chapter to read and answer problems... THANK YOU VERY MUCH FOR THIS VIDEO
dude seriously my teachers need to pull it together as well.
Most of the time, my teacher just throws the material for us to learn and doesn't explain anything in depth. So after awhile, we tend to forget a lot of information due to the fact that we don't actually understand anything but memorize the information. It's videos like these that help so much.
That’s exactly what our teach does
Your comment is from 7 years ago. How fast!
come to think of it. School doesn't rly matter anymore when you have free tutors on youtube who explain the subject better. smh
Can't get a degree from a youtube video tho
You don't need to go to school to get a degree. Homeschooling works just as well.
He prob means college
yeah but school drives you to do better and let's also just say the engineer field would kind of.... go ded.
You don’t need a degree to be a clothing hanger💀
i'm having wars with physic...
SAME!
Same here bruh
Bruh😂😂😂
Sir you cannot even imagine that how easy have you made the things for some students who were struggling with their teachers.
I have no clue what I'm doing in physics, it's so frustratingggg
ikr
Fighting
SAME OMG
phisics can be use to calculating how much gas you need to burn school :0
real
Khan academy use SI units please
metric system please
how is your channel is about gaming and you are seeing this video
?
lolz_kat_XD you are right.
The problem statement regards a US car, where power and acceleration is measured in horsepower and miles per hour. This was a deliberate choice to NOT use SI based on the context.
You guys make it so much simpler than the professors at college ever could.
college? im studying this for 9th grade 0_0
@@icoudntfindaname I'm studying this for 8th
@@bombasticblunderbuss0918 im learning this in 7th
Holy crap I commented this a year ago. I’m now in 9th and still don’t quite understand it. Your comment motivated me to restudy physics and chemistry. So thanks for that lol.
it's nice to find a physicist who's also a car guy XD
Elias Abu Warda he dont know how to say it properly
he also spelt porsche 911 wrong
@@oscar7476 who cares tho lmao
@@notayushgokul07 me cos its a little annoying but at least i learnt something
The correct formula is this:
Acceleration = Final Speed - Starting Speed Divided by time
Or
a=v-u/t
+Abu Aziz when we say Final - initial, it means change in velocity. Same as Sal states at the start.
Aww thanks!
+Abu Aziz Think of it the logical way: It is how much the speed (velocity) of something changes every second, thus we say "per unit time".
+Madison Fulbright preach
Not true ;)
You forgot your operation priorities so it's
a = (v2-v1) / t
Thank you, Your amazing especially during this pandemic!
Its good, i understand all things, thnk u for the explanations
i literally cannot wrap my head around physics im literally sobbing while
doing homework 🥰 hopefully this helps!!!
We can accelerate in circle. Infact any circular motion is accelerated motion because direction of velocity changes at each point of the circular path. And change is velocity is defined as acceleration. So we can accelerate in circles.
When something is travelling in a circle there's always an acceleration. Its called centripetal acceleration and the formula is (Ac=(v^2)/r) Ac being acceleration and r being the radius of the circle
Best video Explaination. I think the dislikes are only for physics and not for Khan academy. Because this guy is a legend.
Thank you for this. Your tutorials are useful especially in this time of pandemic where we go to school through online class which is hard to deal with but you're here, teaching us. Thanks a lot. God bless
For those of you who still don't get it:
20 mph/sec means that for every second the car is increasing it's speed by 20mph.ie,At the first second(t=1) it's speed is 20mph,the 2nd second(t=2) it's speed is 40mph(20+20),the 3rd second it's speed is 60mph(20+20+20) and so on-mph per second.
@mtaFTW you are correct! Will annotate!
Hii
الي ترجم المقطع بالعربي ياخي انت أجمل شخص في العالم ❤❤❤
Shout to khan academy. Khan academy teaches us a lot. Who supports me? Give like and who does not give unlike. My teacher says Read and disappear . Before ending the class period he comes back and gives us another lesson
love physics the beauty of it...
yeah me too.
Just wait until you get to quantum physics
thank you so much , شكرا جزيلا , danke so viel
It`s simple but he made it harder
Yes xD
no, he made it more vast.
Zemo
nah, not really
The direction of an accelerating car is forward. It can't travel directly left or right - up or down, just forward and backward. Reverse acceleration is of little interest, and forward is the direction a car is geared to accelerate the most effectively. The direction inferred by a cars acceleration statistics is forward. Or as the notation you brought = 20mph/sec (+). Where reverse would be (-) and null = 0 mph/sec.
You are right that the car is ALWAYS going forward. Negative acceleration would not be in the reverse direction. It would simple be Deceleration in the forward direction.
Thanks for the help 😭 My science teacher doesn’t make sense and I don’t understand anything until I searched how to solve acceleration. Your video saved me at the last minute because I’m literally up at 2 in the morning studying for a science quiz ;-;
i really wish you were my physics teacher.
Thank god there are people like this that care for kids learning.
I am from India, I see Khan giving free ad for the brand Porsche. With khan academy growing day by day using brand names becomes free ad for those products or services. I think he should consider getting sponsorship from them before using it in his videos, this video has more than 10000 views. They can pay per view and help Free education or change the education system around the world.
I find it much easier to simply convert 60 miles per hour in meters per hour, using a calculator of course (except if someone doesn't need). So 60 mi/h is equal to 26,816 m/s. We divide 26,816 by 3 and we get 8,9 m/s2.
8,9 is indeed 1/180th of a mile, so we got the same result. Also I think that Europeans like me would probably like this method much more, we aren't really familiar with miles.
Oh...I remember learning this in school...(years ago)... This is a great reminder.
much much appreciated, thanks for uploading!
Excellent explanation. "Per second, per second" makes sense to me now!! I was trying learn the equation E=mc2 and wanted to know what is c-square and I ran into your video. Thank you so much KA !!!
Finally I understood the physical meaning for the acceleration !!
thanks Khan :)
I never understood seconds per second or seconds squared until I watched this video. I just couldn't picture it. Thanks so much. I'll be watching a lot more of your video's.
This guy is a hero and public servant for good
Come to think of it ive been using khan acc and it made me smarter- than i was in school-
Is it normal that im a 10 year old watching this in my free time
No but also no one asked
@@walri5312 yeah
cool
lol no not really, but this is helping me (14) with ap physics a lot
Bro your handwriting is awesome! Especially in rush.
My son is studying for a test. This is very useful Sal.
Man Your The Reason Why I Almost Perfect my Exam In Science❤️
*you're
its physics buddy :)
@@andrewreyna376 physics is a branch of science😊.
My best teachar is khan. He reached me a lot . So thanks khan academy 👏🙏
Very nicely explained!
explaining this better than my sci teacher ever can 🙏
"And the entire time you would be pasted to the back of your seat" what an awesome way to end a video XD
It's very pleasant to watch Khan's videos in order like this and always understand everything he says. ^_^
That was best explanation ever. It's so use full to me. Thanks bro.🤗🤗
First of all, ı am Turkish and ı did not understand this issue. thanks to the translation and thanks to you in a very nice way ı’ll follow you now and ı’ll learn again thanks you.(sorry the translation may be wrong)
Great Job Khan Academy. Thank you very much, Mr. Salman Khan, being a maths and science teacher and tutor I enjoyed this lesson thoroughly
THANK YOU SO MUCH YOU ARE A SAVIOR
+YaSaman HF it is because
m/s is velocity. and acceleration is m/s÷time. We denote time here as s=seconds or s/1. Acceleration
=m/s÷s/1
=m/s×1/s
Here both 's' will be in the denominator. When we multiply those two 's' you get s^2.
Hence m/s^2
I am 13 so don't get mad if I did not explain clearly.
It would be better to understand it if you wrote it down in a paper...
That's what physicists do...
Teacher we need u pls continue 🙏
I love physics! with his teaching its easy. we do physics on a daily basis
Khan academy helped me pass evry regent i encountered.... This yr might be different
tysm for such a great video! hopefully ill pass my test now!
...wow. I can't believe how helpful this was.
Learing It In 6th Grade Science thanks for making Acceleration clear to me!
Yes, you can replace mp/h with km/h because you still keep the same 'porportion' when trying to find the acceleration.
You Are Amazing, It Is Like You Are The Next Albert Einstein. Keep The Videos Going Khan! Your The Best!
his name is sal
His voice deep...loving Physics
your handwriting is very neat in the laptop I bet you have been practicing and very good video
honestly this helps alot
Thank you so much! You're a better physics teacher
@tIs4gatorbait What exactly do you mean? The Earth's acceleration is on average always 9.8 m/s^2.
An object does speed up in velocity over time with acceleration applied but that does not mean acceleration itself is speeding up.
For example, an apple dropped to the ground would be moving at 9.8 m/s in 1 second, 19.6 m/s in 2 seconds, etc.
If yall are wondering, the SI unit of acceleration is m/s squared
Thank you,now i understood what is acceleration.But Porsche is spelt porsche not porsh.Once again a lot of thanks.
We’re not even in acceleration we just learned valocity and I needed help went to you and decided to go to this video because I’m intrested
which software are u using to make videos
WOW!!! This was really helpful, Thanks! Hope you are doing well.
Tmr is my exam , after watching ur vids I didn’t need to study
The units for acceleration. This is why in Canada we use Meters per second rather than mph.
Thank you very much Sal for your great videos! I just wanted to note that you forget a "C" on Porsche! haha
You are a better teacher than mine
thank you I couldn't get the information from my school either and I understood your explanation immediately thank you
Thanks
very nice explanation tysm for explaining😊😊😊now it's seems easy
thx for all lessons , i enjoy them all ^^
but i wanted to ask what is the program do u use to explain the lessons ?
Im so happy because you used the numbers 9 & 11 but other than that thanks because I really understand the topic °v°
Very useful for my homework
Sal is really awesome.
i owe everything to you, Sir.
Do physics classes in America use metric units and negative index notation?
Great video by the way.
Beacuse Accleration is V/T
Velocity is m/s and time is s
so when u divide it..it will give u m/s^2
THE MAGENTA THING . Hallarious
Hey,I have a question- a problem solving question.Well,here goes...
A 72 N force accelerates mass m1 by 5.0m/s2.The same force acts on another mass m2 and imparts to it an acceleration of 20.0m/s2.What acceleration will the same force impart to the two masses when they joined together?
Answer it pls cause I REALLY need the answer...
The video is 9:05 long and half of it is you showing us ways of writing the answer 😂 Let me tell you the problem isn't there, it's how to get the answer that most of us is here for.
S its dimensional analysis, you need to know it eventually they have it on the ap test
sir will u please suggest which book to refer for practice?
Karan Dave ha
You have helped me thanks
Helped so much
Adding more numerical to a single video would be nice
THANK YOU
thanks a lot brother that was was very helpful
Acceleration=change in velocity / change in time.. Simple formula
@maveric2170 yes.. it will be much easier if u convert at the start. if question is given in hours or mins. its always better to convert to SI unit.. unless u are asked to give the answer in km/h or so.
istg youtube teaches me better than all the teachers in school.
Squared second?! What is the second? Move of Earth in equator of 460 meters (per second)? Or on poles close to zero meters? Or heart beat of passing life? Or relation between those two? What is the time? How time can be squared? Some basic terms has to be defined, starting from time.