best part about khan academy is that he repeats his words several times and teaches us slowly unlike some math teachers who get finished when you look another way for 5 seconds
i have been watching your videos (chemistry n biology) for a while n it helped me a whole lot. n i think its nice of you to do a vid like this but wat i really like is that u used the fastest man alive which is from jamaica n im from jamaca :)
I recommend mathanyics if you do not like this. Please like, if you try mathantics and you think mathantics is great, try to get this to the top so anybody who watches this can check it out!
The fastest human footspeed on record is 44.72 km/h (27.79 mph), seen during a 100 metres sprint (average speed between the 60th and the 80th meter) by Usain Bolt
you're not considering the fact it would have taken him 20 meters at least to reach full speed. You should have times 50-80m to get an idea of how fast he runs.
Lol. My point is the average speed of Usain in this race includes the first second (and likely few seconds) of him being stationary, and then accelerating to top speed. Therefore taking an average you are going to have a lower speed than his speed as he passes the finish line (top speed). And didn't you know about that the quadrennial pachyderm games held in Botswana? - Where the top speed of an elephant (Barbar indeed) was clocked back in 1962.
I don't like how he compares average speed to instantaneous speed of a charging elephant at the end. :) They 'clocked' Usain at over 27mph in his 100m race.
Okay, I think an approximate equation for velocity with respect to time would be something like v = 27 - 27/(x-1), assuming max speed is 27mph. I wonder if there is a better way to do this.
Yes because 1m=1000mm but 6x1m=6m 6x1000mm=6000m. 6000mm=6m. They are the Same answer but you need to covert the units. (If this wasn’t what you were meaning please give a example
how do we solved this: Supposed the speed of the car had been noted during this time and is modeled by the quadratic equation y = 3x^2 + 17x - 20, where y represents the speed of the car in k,/hr, and x represents the number of minutes after you started following the car. How long did it take for the car to be under surveillance before it could finally stop on the side of the road? Did the driver of the car really break the speed limit of 100 km/hr?
I don't think the comparison to the elephant it that applicable; it's his average speed that you are comparing to an elephant's top speed. I think his top would have been over 40km/h
can someone pls help with this Tom cycled 24 kilometres in 45 minutes. What was his average speed in kilometres per hour? i cant understand it and it is on the sample thing for the end of year STen test pls help
But how do we know who the fastest elephant is? Elephants don't attend a pachyderm games where they find the fastest elephant in the world (we'll call him Babar) and we are comparing Babar's fastest ever clocked time in the 100m sprint to Usain's average. The elephant's charging speed (25mph) is most likely the average.
best part about khan academy is that he repeats his words several times and teaches us slowly unlike some math teachers who get finished when you look another way for 5 seconds
Usain Bolt, fastest human ever: 23.3 MPH
Average Housecat: 30 MPH
The more you know
U dare underestimate the cameraman?
Khan's aim is not to do crash course lessons. He wants you to 110% fully understand what he's teaching.
@JOSIAH MUTUKU yes
i have been watching your videos (chemistry n biology) for a while n it helped me a whole lot. n i think its nice of you to do a vid like this but wat i really like is that u used the fastest man alive which is from jamaica n im from jamaca :)
Your voice is so soothing, I slept on my laptop.
You sound like my substitute teacher.. mom I'm scared.. he's fallowing me again..
I recommend mathanyics if you do not like this. Please like, if you try mathantics and you think mathantics is great, try to get this to the top so anybody who watches this can check it out!
THUMBS UP!!!
Khan should make a vid about what the speed of bolt would be if he were not to chill the last piece of distance
THUMBS UP!!!
Very good explanation love it I understood everything 😊
average speed was 23.35 mph. If we assume his acceleration was constant, then a=2.179 m/s^2, and that give us a finial speed of about 46.7 mph
Awesome video.Perfect real life example.
My guess is that a charging elephant's average speed would be much slower than a human's over 100m from a standstill. ;)
Great work, as always, Sal.
Thanks for telling me
The fastest human footspeed on record is 44.72 km/h (27.79 mph), seen during a 100 metres sprint (average speed between the 60th and the 80th meter) by Usain Bolt
thx this vid rlly helped me
@VanMedia
The reason your velocity increases is if your acceleration is constant.
If someone tell you to do another similar question, can you do it? If you can't you should watch the whole video..
Thank you for telling
You are an awesome teacher, thank you! 👍 👍
you're not considering the fact it would have taken him 20 meters at least to reach full speed. You should have times 50-80m to get an idea of how fast he runs.
Sure let's do it
Dude yousain bolt that's how u prenounce it
jordan miller your wrong
@@XtraFilm-zf8jq you're*
It's actually pronounced "Yoosain"
Usain
You should blur out the average speed that displays on the TV clip at the end of the run.
It says 37.6kph on screen @ 00:31 min
Lol. My point is the average speed of Usain in this race includes the first second (and likely few seconds) of him being stationary, and then accelerating to top speed. Therefore taking an average you are going to have a lower speed than his speed as he passes the finish line (top speed). And didn't you know about that the quadrennial pachyderm games held in Botswana? - Where the top speed of an elephant (Barbar indeed) was clocked back in 1962.
Well if the person is trying to learn the math and understand it the 13 minutes isn't a waste at all.
That is including acceleration/deceleration, but between the beginning and end he reaches speeds of 28mph.
Hey khana, how about the wind speed
He does well, but I sure wish he had a white board. Thanks
How did you figure this out?
By Using his head
I UNDERSTOOD!!:)
Thx
It was 27.6
Beachkiller101 lol
I love how the German tv has this wrong on the screen.
I don't like how he compares average speed to instantaneous speed of a charging elephant at the end. :)
They 'clocked' Usain at over 27mph in his 100m race.
Okay, I think an approximate equation for velocity with respect to time would be something like
v = 27 - 27/(x-1), assuming max speed is 27mph. I wonder if there is a better way to do this.
math man that's hard math
TV says 36.7 km/h
Calculator says 36.44 km/h .. intresting.. ^^
( I know, we rounded of to 10.4 before the end of the problem )
Does anyone know why you get a different answer if you don't convert from m to km before converting from seconds to hours?
Yes because 1m=1000mm but 6x1m=6m 6x1000mm=6000m. 6000mm=6m. They are the Same answer but you need to covert the units.
(If this wasn’t what you were meaning please give a example
I hate how they are 360k views but only 800 likes and 110 dislikes :(
12 year olds should watch
100m/9.58s = 10.44m/s or 23.35 mph (37.57 km/hr)
I just saved you all 13 minutes.
Thx. I still watched the vid, but thx
Yay! German!
commentator: [speaking german] nice captions
So rates are just a quicker form of finding an equivalent ratio?
8:30 in [about] says [sal] 1000x bigger . no, 100x bigger.
how do we solved this: Supposed the speed of the car had been noted during this time and is modeled by the quadratic equation y = 3x^2 + 17x - 20, where y represents the speed of the car in k,/hr, and x represents the number of minutes after you started following the car. How long did it take for the car to be under surveillance before it could finally stop on the side of the road? Did the driver of the car really break the speed limit of 100 km/hr?
That's almost a marathon in an hour if he could keep that speed, which no one does. Even the Kenyans run it in 2 hours and change.
He runs at 37.578288 km/hour.
he said he wanted to see what his "average speed" was in the beginning of the video :)
I'm still hella confused;-;
O_o
I don't think the comparison to the elephant it that applicable; it's his average speed that you are comparing to an elephant's top speed. I think his top would have been over 40km/h
Didn't know elephants were that fast.
german video at the beginning 😂😂😂
oop-
I bet you'd like that.
*he sounds like jschlatt*
That is not his peak speed, however, it is his average rate
looks like sal khan is obsessed with usain bolt and sprinting
can someone pls help with this
Tom cycled 24 kilometres in 45 minutes. What was his average speed in kilometres per hour?
i cant understand it and it is on the sample thing for the end of year STen test pls help
But how do we know who the fastest elephant is? Elephants don't attend a pachyderm games where they find the fastest elephant in the world (we'll call him Babar) and we are comparing Babar's fastest ever clocked time in the 100m sprint to Usain's average. The elephant's charging speed (25mph) is most likely the average.
you really don't need to say intuitive all the time
I would have a name from the lord of the rings but I am a girl!🤣🤣
go Jamaica's Usain Bolt!
Wait the video was published 9 years ago
sorry this is what I meant
v(t) = 27-27/(t-1)
Distance/time, no?
6th
umm, I'm still confused. Help?
Tell me the doubt,I will try to clear it
should be "YOO-sain" Bolt lol
ITS PRONOUNCED yu-sane-bolt
oOUuusain bolt
8st
I just watched a texas tech college football player grant run 26 mph in full pads
Nice lies
Yeah to e is on the Dolphins now lol he is vary fast!
not sure if trolling or...
Okki first of all it is U(you)sane not ousaine
Khan is calling Usain slow! inb4JamaicaRioters! xD
10.4 m/s is his average speed
Clearly, but he has to make the videos for a broad audience. He can't just assume that everyone knows basic mechanics.
isnt it just a little over ten m/s?
No he hasn't done LAW yet
13:00 your numbers and significant figures are incorrect.
ooosain bolt
It's hard to focus with that huge picture in the middle of the screen
The man's name is pronounced uuu-Sain not ooooo-sain
I mean mathantics
Im still super confused
But the reaction time was like 0.14 seconds so the speed is a bit faster. But nice video any way.
Wasn't it 2008?
coo
*AVERAGE RATE*
23 miles for all the lazy ppl who did not want to watch :3
We don't wanna just know the answer, the whole point you would click on this video is to know how to do it.
geez? isn't it jeez?
lol he had a csgo crosshair to write with
Christian P. Ikr
@pureexpose it doesn't make you any better to talk down to people like that
Nope. OO-sain, He is Jamaican
hmmmmm, I want to know his maximum speed....
lol of course he gets tired.
He just runs faster while he's tired.
whatchu doin here jayex23?
lol his 200m record is only 3 hundredths of a second off of double his 100m record
Ouuu sain bolt 😭😭😭🤣
Oosain Bolt???? LOOOL.