@@ryanechelberger7035 Yes, but his channel was created because he started out with helping people for free, and he insists that people should be able to use it for free without being forced to pay for it.
I believe the typical flaw of many physics teachers is that they don't really explain things in-depth, they just shove formulas into your face and tell you to calculate something. Anyone can put numbers into formulas, the real challenge in physics is to actually understand what's going on and WHY the formulas look the way they do. Khan is very good at explaining those kinds of things, and it gives you a much better intuition.
Thank you so much! I was feeling a little shaky about a few things for my Physics exam that I forgot to ask my teacher, and these videos have really cleared things up!
Hey Sal, I remember hearing you say you can code too. You are a brilliant teacher, could you do some video tutorials on C++ or some other programming language? Its a lot to ask but it'd be amazing... thanks anyway man.
Sal, I am a retired former physicist trying to relearn what I used to know. Can you please tell me what grade level physics you are targeting? Since I have not looked or thought of physics for 40 years, I am having a ball with your videos.
When I am in class, I'm like, "GOD WHAT CAN'T THIS PHYSICS CLASS BE SHORTER..." When I am watching this video, I'm like, "GOD WHY CANT THIS VIDEO BE LONGER..." ;)
wow when he says that he has run out of time bc the video was posted in 2008 and YT videos could only be uploaded at 10 minutes max. Oh how the days have changed.
All your videos there is one thing common...at some point in the explanation you hit the bulls eye of explaining the logic behind the topic..that makes it interesting rather than blindly bye hearting the formulas...Thank you very much..
Watching your videos always makes me envy the kind of education developed countries get, where i'm from physics might as well be math with different units ..
+YES! Yes! How rude and arrogant! She's voicing her opinion, there's no need to judge her. Moreover, you know nothing about where's she's from or the struggles she has, so don't try and act like it's nothing. We all have problems in life, and yes...the environemnt does matter. Some students simply don't have the same opportunities and facilities as others, and this is an universal fact. Furthermore, an overwhelming percent of the time it DOES create an impact on the future of the students. So focus on your own life, and keep your negative attitude outside of others'.
I can tell you as a student that often students don't want to be in lessons or don't care about what their teacher is saying, but if a student stays around long enough to watch a video then they definitely care enough about the topic or like way it's taught and it's a convenient time for them. Hence students always find educational videos more convenient and hence better.
Because lots of teachers don't fully understand what they are teaching. They know how to get the right answer, in terms of using the formulas correctly, but I bet you they couldn't break down what that formula is actually doing... They don't understand WHY the formula works essentially. Don't get me wrong there a lots of awesome teachers (from my experience at least), but there are also too many that simply teach the curriculum, without an in-depth understanding of what they teach.
Yeah, noticed that, too. I love when I understand well enough in the beginning to recognize a mistake later on in the video. Makes me feel a bit confused but also let's me know I understand well enough to even recognize mistakes.
"Hooke's law states that the force produced by a compressed spring is dependent on the amount by which the spring is compressed. If a spring compressed by 1 cm requires a force of 1 newton, then compressing the same spring by 2cm will require 2 newtons of force."
@NPowah But spring force should be in the opposite direction...I thiink Sal is wrong, because the APPLIED force he used was (+2 N) and the restorative force (spring force) he put down was (+2 N). He's solving for K, so conceptually, he should put down the correct F to get the correct K. If he was solving for F, then yea, the (-) would factor itself in to get the spring force (F) in the opposite direction and all you would need to worry about is getting the correct sign for distance.
Cause Physics can't explain jackshit. (Well, in my case my teacher teaches so slow and so incoherently that everyone falls asleep and no one learns anything except those people who already know all of AP Physics)
Shouldn't the value of K in the last example be positive due to the fact that the force isn't put to compress? In that way it's negative from the beginning, -2N to counteract the positive force of 2N?
You would have to watch Khan for a month or so without a break in order to watch all their videos. I just calculated it assuming the videos average 10 min in length. Better start somewhere...;)
he assumed that (k) is positive for all purposes and if k is negative number besides the negative sign and x for example in the positive direction the conservation force would be in the same direction and the same if x in the negative direction which is wrong
Wouldn't k in the second equation be 2 and not -2? Since he's applying the force in the positive direction, the restorative force would be negative, so -2=k*1, so k=-2? Isn't that what he did in the first example?
So, to make a three inch long shock absorber (.076 meters) for a cane, that will support a body weight of 220 pounds (979 N), then F = 979 N = .076 × k k = 979N / .076 = 12,882 If I am willing to double the length of the shock absorber, then k = 6,441, which might be cheaper.
Spring Constant. Kinda like the strength of the spring. Every spring is different, some harder to pull/push than others. The spring constant just represents that.
Levi Nordmann K's SI unit is Newton's per Meter (N/m) or Kilograms per Second squared (Kg/s^2). You can find the spring constant from the formula F=-kX, where F is the force required to extend or compress the spring, k is the spring constant, and X is the distance the spring is stretched or compressed. Really I just googled it all. If you need help Google can always provide quick and specific answers. Hope I helped!
Since this is an earlier video, maybe he wasn't as used to the software as he is now. Now he doesn't waste as much time with these things. At least this is what I think.
I think the people who go out of their way to put videos up on youtube for free generally have an enthusiasm that not all teachers have (some anyway)
He makes money off the video though
@@ryanechelberger7035 it is still generous of him, how much he could be making from online paid courses isnt even close to what he makes from youtube.
@@ryanechelberger7035 Yes, but his channel was created because he started out with helping people for free, and he insists that people should be able to use it for free without being forced to pay for it.
its a fundraiser
@@ryanechelberger7035
I believe the typical flaw of many physics teachers is that they don't really explain things in-depth, they just shove formulas into your face and tell you to calculate something.
Anyone can put numbers into formulas, the real challenge in physics is to actually understand what's going on and WHY the formulas look the way they do.
Khan is very good at explaining those kinds of things, and it gives you a much better intuition.
so true
Good ol' days of 240p Khan Academy
lmao
lmao 2021 now XD
:D
X)
Im late to the party, ap physics 1 here trying to get a 5
Why wasn't the restorative force in the last example -2N instead of 2N since it was acting to the left?
Thank you so much! I was feeling a little shaky about a few things for my Physics exam that I forgot to ask my teacher, and these videos have really cleared things up!
You totally kick my professor's ass.
mine too, my online class is a joke.
Hey Sal, I remember hearing you say you can code too.
You are a brilliant teacher, could you do some video tutorials on C++ or some other programming language? Its a lot to ask but it'd be amazing... thanks anyway man.
Wow 12 years ago
Wow 1 year ago
@@jovany4163 wow 8 days ago
@@poppyqueen7894 wow 3 days ago
@@lenny91 wow 2 minutes ago
click the little settings cog and above quality change the speed to 1.5. exams are too soooon
Saaaameee literally tmr
Lol, I have my SAT Subject Tests tomorrow (2nd November)
@Jesus bruh, it's been so long
Sal, I am a retired former physicist trying to relearn what I used to know. Can you please tell me what grade level physics you are targeting?
Since I have not looked or thought of physics for 40 years, I am having a ball with your videos.
Most likely this Stern dude is dead by now.
14 years ago 😳 Im assuming high school
Yeah sophomores juniors and seniors that’s who’s in my class
When I am in class, I'm like, "GOD WHAT CAN'T THIS PHYSICS CLASS BE SHORTER..." When I am watching this video, I'm like, "GOD WHY CANT THIS VIDEO BE LONGER..." ;)
wow when he says that he has run out of time bc the video was posted in 2008 and YT videos could only be uploaded at 10 minutes max. Oh how the days have changed.
skip forward a few seconds if it isnt loading
All your videos there is one thing common...at some point in the explanation you hit the bulls eye of explaining the logic behind the topic..that makes it interesting rather than blindly bye hearting the formulas...Thank you very much..
Wow 11 years ago
Over a decade
Watching your videos always makes me envy the kind of education developed countries get, where i'm from physics might as well be math with different units ..
keep blaming your environment. Fucking loser .
+YES! Yes! How rude and arrogant! She's voicing her opinion, there's no need to judge her. Moreover, you know nothing about where's she's from or the struggles she has, so don't try and act like it's nothing. We all have problems in life, and yes...the environemnt does matter. Some students simply don't have the same opportunities and facilities as others, and this is an universal fact. Furthermore, an overwhelming percent of the time it DOES create an impact on the future of the students. So focus on your own life, and keep your negative attitude outside of others'.
I completely agree with you iMusikkForeva.
You have a notification
This video is older than me, yet here I am using it
go to settings put the graphics to 240p and it will surely work :}
Video won't load...
In the last example, why the sign of restoring force is positive?
Mini mistake ig, it should be -ve
Thank you so much(: Love the video, it really helped me alot A LOT(: May God Bless YOU(:
Ok
you have come a long way sal
KHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAN!!!!!!!!
video doesnt load for me, tried it on both youtube and khanacademy site, doesnt work
try it in 240p, i was having the same problem, but 240p worked for me.
Nathan Cameron thx mate really needed that :)
Who doesn't understand physics like me?
Not me!!!
Imagine not understanding physics, must be sad
Thanks for the great expanation! May the FORCE be with you :)
When u pulled the spring 2N to the right the Resistance force is -2N. and since you move 1 meter,
F= - K X
-2N= -k * 1m
k= 2 not -2
its crazy that this video is older than I am
20 metres? that is a lonnnnng spring
Ikr
"If you stretch something too much, it never really goes back to where it was before"... I lol'ed xD
Awesome videos, btw. Keep going!
Dang you commented this back in 2009
@@laimfz I guess I did.
@@MulleDK19 you must be old now.. 12 long years
How are you doing now?
14 years man. Are you still alive?
I can tell you as a student that often students don't want to be in lessons or don't care about what their teacher is saying, but if a student stays around long enough to watch a video then they definitely care enough about the topic or like way it's taught and it's a convenient time for them. Hence students always find educational videos more convenient and hence better.
-5N to the left direction (as drawn) means 5N to the right
These people actually know how to teach, verses others that attempt to teach.
Thank you!
10 meters?! Now thats one big spring!
Bigger than your c ...
Hooke's law states that the extension of a spring is directly proportionate to the force applied.
within the limit of proprtionality
What
You're right. K should be 2 in the last equation.
Surely the signs for the last question would have to change??
@ mygremg
Sal is actually correct, since he is discussing the Force of the spring, which is F = -kx
Because lots of teachers don't fully understand what they are teaching. They know how to get the right answer, in terms of using the formulas correctly, but I bet you they couldn't break down what that formula is actually doing... They don't understand WHY the formula works essentially. Don't get me wrong there a lots of awesome teachers (from my experience at least), but there are also too many that simply teach the curriculum, without an in-depth understanding of what they teach.
Restorative force for the last example is NEGATIVE 2; I think Khan put positive 2 by mistake
youre right
Yeah, noticed that, too.
I love when I understand well enough in the beginning to recognize a mistake later on in the video. Makes me feel a bit confused but also let's me know I understand well enough to even recognize mistakes.
Lol king Barney? Not on skate or mortal combat videos? Get outta here
Simon Talamantes Hahaha. Got a final exam in 4 hours. xD
How'd ya do Barney?
"Hooke's law states that the force produced by a compressed spring is dependent on the amount by which the spring is compressed. If a spring compressed by 1 cm requires a force of 1 newton, then compressing the same spring by 2cm will require 2 newtons of force."
@NPowah But spring force should be in the opposite direction...I thiink Sal is wrong, because the APPLIED force he used was (+2 N) and the restorative force (spring force) he put down was (+2 N). He's solving for K, so conceptually, he should put down the correct F to get the correct K. If he was solving for F, then yea, the (-) would factor itself in to get the spring force (F) in the opposite direction and all you would need to worry about is getting the correct sign for distance.
Thank you
newton must feel like such a badass, forget a building or even a species or a star, he has a force of nature named after him.
Is there a Springe's law for hook physics?
this joke went unappreciated for 9 years...but I'm here for you. I laughed.
@@andrewm2786
I've been waiting for this moment for 9 years :_)
@@bananian you must be long done school at this point
@@haroonk.9706 yea, let's see
Thanks khan academy
helped me alot thanku so much
Getting this on my test ;)
thanks Mr. Khan.
i can always rely on you
I fell asleep in my physics class explaining springs and Hookes Law, this video is a total lifesaver
can u go into finite element analysis
how does the 1/2 part come into play in the restoring force =-kx formula
11 years later and we are all still here
I know right
Cause Physics can't explain jackshit. (Well, in my case my teacher teaches so slow and so incoherently that everyone falls asleep and no one learns anything except those people who already know all of AP Physics)
thank you! very useful.
Shouldn't the value of K in the last example be positive due to the fact that the force isn't put to compress? In that way it's negative from the beginning, -2N to counteract the positive force of 2N?
can someone please explain what k is in hookes law?
k is a constant that is, its a number
Thanks so much
how do we join your academy?
I was only 3 when this was released and now Its finally my turn.
What does Hooke's law depend on?
Would gravity have the same effect on a spring that is attached to a roof/ceiling?
At the end of the video, why isnt the restorative force -2 since its acting in the opposite direction?
Ty
Wouldn’t F=2x in the last example ? Since u had k = -2 therefore -(-2)x would be the function
so F is not the applied force?
in the last question isn't restorative force -2 Newton cause it's acting towards the left?
X is 847375
I bet he has a higher pass rate than your "professional and organized" teacher who prepares for classes
You would have to watch Khan for a month or so without a break in order to watch all their videos. I just calculated it assuming the videos average 10 min in length. Better start somewhere...;)
thanks loads :D
This man is god
So even if I move a car by distance x or if I move a pin by the same distance X then the force applied by me is the same for both cases ??
isnt it supposed to be f=-(-2)x for the 2nd question? anyone?
Yes, that's exactly what I was thinking!
yes
he assumed that (k) is positive for all purposes and if k is negative number besides the negative sign and x for example in the positive direction the conservation force would be in the same direction and the same if x in the negative direction which is wrong
yes i think he created another video to correct this
thnx sal
Wouldn't k in the second equation be 2 and not -2? Since he's applying the force in the positive direction, the restorative force would be negative, so -2=k*1, so k=-2? Isn't that what he did in the first example?
No idea mate
But if the spring is at rest the restoring force must be zero?
The spring is only at rest because you're still pushing on it. If you stopped pushing it would spring back at you. *That's* the restorative force :)
If I take positive X to right and negative to left since force is also a vector quantity shouldn't it b negative to left as well?
Can you make video about elasticity please?
I wish they would redevelop these videos
the quality of the video looks like it was recorded using a calculator
the force is strong in this one
hold on a second so is the last question right or is gregme right
may i asked why the formula is F= -kx ? because in my textbook and reference books it said F = kx
love you KHAN
@LOLzxcvb the spring constant, its different for different types of springs and shows how stiff a spring is.
Good
Why isn't the video loading?
try changing the speed of the video to 1.25 or 1.5 or just click midway into the vid lol. Worked for me.
So, to make a three inch long shock absorber (.076 meters) for a cane, that will support a body weight of 220 pounds (979 N), then
F = 979 N = .076 × k
k = 979N / .076 = 12,882
If I am willing to double the length of the shock absorber, then k = 6,441, which might be cheaper.
Its fine now
To the left to the left
Useful video but not the one looking for. Like
00.26. That's what he said
he doesn't need to prepare he's amazing
ya
what exactly is K?
Spring Constant. Kinda like the strength of the spring. Every spring is different, some harder to pull/push than others. The spring constant just represents that.
King Barney hello king barney, but in what is K measured? And how do I get the spring constant? It'd be great if you could help
Levi Nordmann K's SI unit is Newton's per Meter (N/m) or Kilograms per Second squared (Kg/s^2). You can find the spring constant from the formula F=-kX, where F is the force required to extend or compress the spring, k is the spring constant, and X is the distance the spring is stretched or compressed. Really I just googled it all. If you need help Google can always provide quick and specific answers. Hope I helped!
Why dnt u draw dia in advance
Oh my god when this video was uploaded I was just 1 month old
yeah I figured that out later
240p This is HD RUclips quality right here!
made in 2008
he's really good at explaining, but he spends tooooo much time drawing and wasting time over silly things
play the video at 1.25 or 1.5 times the original speed
Since this is an earlier video, maybe he wasn't as used to the software as he is now. Now he doesn't waste as much time with these things. At least this is what I think.
clearly you were not paying attention my friend hahahahahaha who cares when you need to learn?
I think it’s good for people who need more time to process.