I believe he made an error in the calculation cuz I get distance to be 643.125 m, nevertheless method is correct. Not that it couldn't have been done in any other way.
sal doesn't make a mistake. The reason why he mutiply by 3600 is because he got the deceleration of the train in m/s. he needs to gets it to km/h. So that it matchs the initial velocity of the train which is 8 km/h. In order to convert m/s to km/h. you need to multuply m x 3600 =h. divide it by 1000 to get it in km instead of m.
@bkjoelover Since seconds/hours is in the denominator, we would be dividing the divisor (which is like dividing by a fraction), so instead we just multiply.
eg. 1/200. If we divide the two hundred by 100, this is equivalent to multiplying the entire fraction by 100: in their case we end up with 1/2 after reducing.
instead of leaving 80 as km/h, I convert it to 22.2 m/s and on the final question about distance, I got a different number, 1712.5m. Is it still correct? Where did I go wrong?
I am very happy to see the vidoe A problem involving a braking train after you give this
Kricardose 1 month ago
I Love The Video It Can Increase My Knowledge A problem involving a braking train.
bebeheuy 1 month ago
Steady I Really Like This Video A problem involving a braking train
Mjhond 1 month ago
Thanks for these video.
MrPEDOCTOR 2 months ago
my science 10 pIB teacher uses ur vids all the time
(That's impressive considering she's full of herself)
but good job though!!!!
TheHajiman 5 months ago
Can you do some videos on relative motion in 1D and 2D?
AnonymousJoelee 5 months ago in playlist More videos from khanacademy
This is amazing, really love what your doing. I really need the extra help and it feels like your right here with me, thank you .
asidewalk 1 year ago
how do you make it so easy?
Taowhr 1 year ago 5
you save lives.
KxSoul24 2 years ago 22
A problem involving a braking train.
TheKing0fKingz1 2 years ago
The handy calculator!
ezboss7 2 years ago
the calculation is correct thx
metalking0206 2 years ago
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TruthLogic 2 years ago
I believe he made an error in the calculation cuz I get distance to be 643.125 m, nevertheless method is correct. Not that it couldn't have been done in any other way.
ua24986 2 years ago
sal doesn't make a mistake. The reason why he mutiply by 3600 is because he got the deceleration of the train in m/s. he needs to gets it to km/h. So that it matchs the initial velocity of the train which is 8 km/h. In order to convert m/s to km/h. you need to multuply m x 3600 =h. divide it by 1000 to get it in km instead of m.
MMX0710 2 years ago
well...it is just a number....the method itself is correct
maybeok1 3 years ago
yea im confused also y is it multiply by 3600....
bangalirussian 3 years ago
Sal did not make a mistake. Do the problem over.
ydultm 3 years ago
sal u need weed to get u runnin like da old sal....
bangalirussian 3 years ago
why do you multiply by 3600 and not divide it by 3600?
bkjoelover 3 years ago
@bkjoelover Since seconds/hours is in the denominator, we would be dividing the divisor (which is like dividing by a fraction), so instead we just multiply.
eg. 1/200. If we divide the two hundred by 100, this is equivalent to multiplying the entire fraction by 100: in their case we end up with 1/2 after reducing.
adeimantius 1 year ago 2
@bkjoelover Yeah, divide by 3,6, km/h -> m/s and multiply by 3,6, m/s -> km/h
raptusss 1 year ago
instead of leaving 80 as km/h, I convert it to 22.2 m/s and on the final question about distance, I got a different number, 1712.5m. Is it still correct? Where did I go wrong?
Latias07 3 years ago
sal made a mistake
bangalirussian 3 years ago