We made quiz questions to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/3TW06aP
She kept me totally focused for nine minutes and twenty six seconds and i learned lots of new stuffs i did not know before!. Really shows that you guys are getting more and more professional.
2:45 The fact that phys is a required course for Computer science majors with a concentration in game development and crash course incorporates video game references in these videos makes learning all the more enjoyable!
just an idea, you should have an app where you can compete in a quiz with a stranger based on the material from your videos. It would help learn better.
Great video. I'm close to 70 and live in the US, but when I was her age, we pronounced about 73% percent of all those big words differently :-) , Love it. I could listen to this video a dozen times. (and might have to . . . and take notes)
I remember when i was back in 8th grade i couldn't understand a thing she said. I jus thought she was one bad teacher with crash course. now in tenth grade, this is the most clear explanation i have found yet. Thanks!!
No idea is original, everything stems from something. To brake it down the more you understand the basics, the easier all the new stuff gets. You can't have the newest phone with out starting with the Nokia brick A.K.A THE OG (the struggle was real).
"We're just here to make sure the ride is safe, we're not responsible to clean up all the vomit after the ride is over" Bahahaha, I'm sure the engineers agree xD
Hey guys, awesome videos ! You guys have been teaching me material non stop all the way from grade 10 Advanced Biology to first year university Psychology and I just wanted to thank you for all your dedication and hard work ! I just transferred from a BSc to BEng and am studying to become a Material Engineer so I'm taking several physics courses in the spring/summer and am exactly where you guys are right now(Video Wise) ! P.S. I think I've gotten almost all my friends to watch your vidoes if they need help ! :D Thanks for all the dedication guys !
Yeah, I get annoyed when I try and explain physics to people and they refuse to use fictitious forces. Because "their not real" Actually, you can think of fictitious forces as forces experienced due to being confined to a surface during motion. Because that is an entire field of math in its own, simply using forces produced relative to the object on the confining surface is stupidly efficient and true to what you actually experience.
H20Falcon But dont satellites work because of gravity and something like centrifugal force? If they slow down the gravity would eventually suck them in, but if they go too fast they will break orbit.
It's interesting to notice that as we go further into these videos, the explanations make more and more (intuitive) sense. That's is great course outline work, folks!
1.Lets prove a = v^2/r if v = (2 x pi x r)/T 2.v= (2 x pi x r)/T 3.using chain rule 4.dv/dr x dr/dt = dv/dt = a 5.therefore dv/dr x v = a 6.dv /dr = (2 x pi) / T 7.dv/dr x v = ((2 x pi)/T) x ((2x pi x r)/T) 8.dv/dr x v = (4 x pi^2 x r)/T^2 9.dv/dr x v = (((2 x pi x r) / T)^2 )/r 10.we know that v = (2 x pi x r) / T 11.therefore 12dv /dr x v = v^2 / r 13.hence 14.a = v^2/r 15. Q.E.D if anyone is confused at 9 a quick expansion shows that line 9 equals line 8.
"4.dv/dr x dr/dt = dv/dt = a 5.therefore dv/dr x v = a" I can't see the leap of logic u made from 4 to 5. When u say "dv/dr x v", r u saying that v is dr/dt? I that it v was dc/dt (where c is circumference).
Sideeq Mohammad Simple chain rule is at work here. dv/dr x dr/dt =dv/dt , think of it like the dr's cancelling but the actual proof for chain rule is quiet long. we know dr/dt is basically the rate of change in distance and we all know that is velocity.dr can be exchanged for dx here thus dr/dt = v hence dv/dr x v = dv/dt = a.
Mo Killem Ok Im familiar with chain rule now but, as an aside, shouldn't dr/dt=0? After all, dr/dt is the rate of change of the RADIUS with respect to time. But the length of the radius NEVER changes in uniform circular motion.
Sideeq Mohammad It doesnt change in magnitude however it changes in direction and hence it does have a rate of change.After all displacement is a vector.
Too bad this was posted after the AP Physics Mechanics test! Still a great video and I am happy that Crash Course isn't afraid of covering a math heavy subject like physics.
You videos have helped me so much in Physics. I couldn't find any reliable, informative and yet interesting video like these ones. I can't thank you enough. I'm more than thankful to you. 😊😊😇😇
When you stir the cup, water is forced outward because of centrifugal force, the same sensation you get when riding a carousel. This makes the pressure higher towards the edge of the cup. Close to the bottom of the cup friction between the fluid and the cup forces the swirling motion of the water to slow down and this in turn makes it possible for the pressure difference to establish a current towards the center of the cup that is stronger than the centrifugal force.
this came at the right time to reinforce what i already knew about circular motion in a cool, graphical way for my exam tomorrow. Thanks for this upload!
I am very please to see a woman explaining things that used to be mainly in the domain of men. Very well done young lady, my hat is off to you. BRAVO !
+TalenGryphon Except no, because in normal operation you're not spinning it in a circle. Flying Wii-motes is not a demonstration of tangential velocity, it's just throwing the thing at your tv. Agreed, though, people should use the wrist strap.
Thank you so much! In our intro to uniform circular motion, we rushed through some derivations, and the concept wasn't really explained. Thank you for putting words to variables and numbers!
Ahh, wish these physics topics were already finished lol, woudve helped so so much in my physics exam just like how much it has helped me in bio and chem! Found the biology 8402 igcse paper 1 so easy mostly because of CrashCourse!
I swear I had to replay this one 4 times just to figure out what was the difference between the analogy of the car versus the key lol. I love watching things that make me go grab a pen lol.
I'm studying for my senior year physics exam so I'm no expert but I'm 99.99% sure this vid is correct on the centrifugal force being a fictitious force
Not true, the action/reaction pair do *not* affect the same object: the centripetal force applied to the object is the tension force from the string, the object exerts a reaction force *on the string* , this reaction force has no interest to us since we are studying the rotating object not the string. To realize why the Centrifugal force is not real, just examine what happens when we cut the string: there is no more Centripetal force so the object moves along a straight line that is a tangent to the circle (in the direction of the Velocity at the moment the string was cut). If there where an actual Centrifugal force, the object should have moved in a straight radial line *perpendicular to the tangent* , which is not what happens in real life.
@@mjsaedy6637 You say:"Not true, the action/reaction pair do not affect the same object:" Of course they don't, if they did they would cancel each other out. When you swing a ball on a string your hand exert a centripetal force on the ball which reacts by exerting a centrifugal force on your hand and it is obvious these forces pass through the string. You thus have an action/reaction force pair that obeys Newton's Third Law.
Thankyou! Khans couldn't help, my physocs teacher is useless, and this is one of the only times I actually understand what it is we're doing in that class
Shini could explain anything and I would listen wholeheartedly. Can we crowd fund her to record a phone alarm so I can stop hitting snooze? That, or you know... just persuade her to dub over my Discrete Mathematics professor.
5:10 Isn't this simply Newton's Third Law though ? The ride itself pushes against you so your body has an equal opposite force, this is the force that you feel pushing you against the wall...
Well, Newton's 3rd Law occurs between 2 objects. Yes. The wall pushes against you while you push against the wall - the 3rd Law. But what's pushing YOU against the wall? Nothing, really. You would move in a straight line - if not for the wall pushing you toward the centre of the ride. This is why that outward force is deemed fictitious.
When you are spinning, the ride itself (the seat you're sitting on) is connected to the center, and it experiences tension force as centripetal force. You, however, aren't directly connected to the center of the ride so there is no tension force pulling you inwards. Your inertia makes you move in a straight line tangent to the circle. However, the wall of the ride is in the way, and exerts an equal and opposite force on your body, keeping you from going in a straight line, and that normal force is centripetal force for you. So basically what you feel isn't normal force, it's your inertia. Normal force is what's keeping you on the circular path.
Lizgony No sir that's the misconception about centripetal force it doesn't exist. It feels like it but the ride isn't the reason for flying off or feeling pressed.
These videos are so informative and I love learning about it But it super-helps that the host is amazingly beautiful and not a VlogBrother (no offense meant, I love the brothers too!)
Uniform circular motion is fun. Rotational dynamics, though...I could never get my head around that. I understood relativity perfectly fine, but as soon as we started discussing torque, I was so lost. It didn't help that I had a professor whose answer to "where did that equation come from" was just to write more equations on the board with little to no added explanation...
We made quiz questions to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/3TW06aP
She kept me totally focused for nine minutes and twenty six seconds and i learned lots of new stuffs i did not know before!. Really shows that you guys are getting more and more professional.
Great, now I lost my key.
I lost my ignorance :)
I use a Knife
My key is safe
That flying Hit my brother and now his gone.
Lol i have no Brother.
@@carmelogonzales5053 not any more
2:45 The fact that phys is a required course for Computer science majors with a concentration in game development and crash course incorporates video game references in these videos makes learning all the more enjoyable!
just an idea, you should have an app where you can compete in a quiz with a stranger based on the material from your videos. It would help learn better.
quizup
or quizizz
This is a brilliant idea to increase revenue and viewer count... CRASH COURSE! LOOK AT THIS!!!
Mufaddal Ezzi quizcourse
so a review just do quizlet
Please god someone fix that Rubik's cube I'm dyin here
+Holly Panetta I have bad news for you ;)
+thelonelydirector :(
Blame Hank, he's the one who started playing with the cube in a meeting and now it's forever that way. FOREVER!
+thelonelydirector :(( my poor order-loving brain can't take this
When I play rubic's cube sometimes I cheat it
Great video. I'm close to 70 and live in the US, but when I was her age, we pronounced about 73% percent of all those big words differently :-) , Love it. I could listen to this video a dozen times. (and might have to . . . and take notes)
I am at the bottom of motivation atm and I have a physics/chemistry exam in 1.5 weeks. So nice to have easy "lectures" on youtube. Thank you guys!
Hank is looking good!
+leein jeon Hank usually hosts the CCs that are filmed in Montana.
Who the eff is Hank?
DJBsLectures I hope this is the first video you watched on this channel.
+drink15 store.dftba.com/collections/vlogbrothers/products/who-the-eff-is-hank-poster
DJBsLectures OOOOOoooooo. Well played sir!
I remember when i was back in 8th grade i couldn't understand a thing she said. I jus thought she was one bad teacher with crash course. now in tenth grade, this is the most clear explanation i have found yet. Thanks!!
No idea is original, everything stems from something. To brake it down the more you understand the basics, the easier all the new stuff gets. You can't have the newest phone with out starting with the Nokia brick A.K.A THE OG (the struggle was real).
"We're just here to make sure the ride is safe, we're not responsible to clean up all the vomit after the ride is over"
Bahahaha, I'm sure the engineers agree xD
+Vectored Thrust That's the rocket builders motto
Last video 5 years ago bruh 😃😅
currently watching this 3 hours before my AP test. god bless your soul
Bless you guys, this has practically saved my GPA. So much easier to understand than what's taught in school
You spin me right round... Thank you for your time.
😂 nice one 😂
I just failed my ap test this week, really could have used this earlier rip
+Yale Benson I mean... I usually know when I've failed an exam.
+CrashCourse ya... Not answering half of it was my first clue
Can't you re sit the test?! 😪
+Dan Gilbert
Learning sometimes helps .. just a thought
This video wouldn't have helped you on the AP at all.
1:21
I was pretty concentrated on the video and thought I was just about to pass out.
Well played. 10/10.
Hey guys, awesome videos ! You guys have been teaching me material non stop all the way from grade 10 Advanced Biology to first year university Psychology and I just wanted to thank you for all your dedication and hard work ! I just transferred from a BSc to BEng and am studying to become a Material Engineer so I'm taking several physics courses in the spring/summer and am exactly where you guys are right now(Video Wise) ! P.S. I think I've gotten almost all my friends to watch your vidoes if they need help ! :D Thanks for all the dedication guys !
Circular motion was my favorite section of physics last year, awesome video!
Why did I live to the age of 34 before I found out that centrifugal force doesn't exist??
+realmenchangediapers It exists relatively speaking.
Yeah, I get annoyed when I try and explain physics to people and they refuse to use fictitious forces. Because "their not real"
Actually, you can think of fictitious forces as forces experienced due to being confined to a surface during motion. Because that is an entire field of math in its own, simply using forces produced relative to the object on the confining surface is stupidly efficient and true to what you actually experience.
i found that out in a Horrible Science book, when I was in sixth grade
So if it doesn't exist, why do we build things based on it and they work perfectly?
H20Falcon But dont satellites work because of gravity and something like centrifugal force? If they slow down the gravity would eventually suck them in, but if they go too fast they will break orbit.
I love that you explained how the variables in each equation made sense in reality, that's the one thing that was keeping me from understanding
I'm in university physics and these videos are incredibly helpful! Thank you
It's interesting to notice that as we go further into these videos, the explanations make more and more (intuitive) sense.
That's is great course outline work, folks!
Why is Crash Course always awesome? Is there some quantifiable element?
+James Craver CC Physics is 2.7 less quantum units of awesomeness than CC Government and Politics (no eagle punching is negative factor).
+James Craver
Now I know from where Kurzgesagt seeks for materials, haha
Kurzgesagt is awesome!
+Bananaman Agreed (I'm a patron with a bird profile pic; not actually affiliated with them)
It smells like months of hard work Famm
This will save me in the physics exam in 12 days
+SotraEngine4 Sounds like you need a better physics class.
SotraEngine4 same
this will save me on the physics exam in 16 hours. and i have the flu.
The key turning 'experiment' is basically how discus throwers don't knock out anyone standing beside/behind them.
@Dr. Shini Somara
You're just the whole package. I could listen to you could talk physics for hours. :)
1.Lets prove a = v^2/r if v = (2 x pi x r)/T
2.v= (2 x pi x r)/T
3.using chain rule
4.dv/dr x dr/dt = dv/dt = a
5.therefore dv/dr x v = a
6.dv /dr = (2 x pi) / T
7.dv/dr x v = ((2 x pi)/T) x ((2x pi x r)/T)
8.dv/dr x v = (4 x pi^2 x r)/T^2
9.dv/dr x v = (((2 x pi x r) / T)^2 )/r
10.we know that v = (2 x pi x r) / T
11.therefore
12dv /dr x v = v^2 / r
13.hence
14.a = v^2/r
15. Q.E.D
if anyone is confused at 9 a quick expansion shows that line 9 equals line 8.
"4.dv/dr x dr/dt = dv/dt = a
5.therefore dv/dr x v = a"
I can't see the leap of logic u made from 4 to 5. When u say "dv/dr x v", r u saying that v is dr/dt? I that it v was dc/dt (where c is circumference).
Sideeq Mohammad Simple chain rule is at work here.
dv/dr x dr/dt =dv/dt , think of it like the dr's cancelling but the actual proof for chain rule is quiet long.
we know dr/dt is basically the rate of change in distance and we all know that is velocity.dr can be exchanged for dx here thus dr/dt = v
hence dv/dr x v = dv/dt = a.
Mo Killem Ok Im familiar with chain rule now but, as an aside, shouldn't dr/dt=0? After all, dr/dt is the rate of change of the RADIUS with respect to time. But the length of the radius NEVER changes in uniform circular motion.
Sideeq Mohammad It doesnt change in magnitude however it changes in direction and hence it does have a rate of change.After all displacement is a vector.
Mo Killem O ok sanks 4 clearing dat up
Damn these physics crash courses are super clear! I hope it'll help a lot of people struggling with their mechanics class :)
2:47 Oh hi there, Link! How are you?
CRASH COURSE IS IMPORTANT ALWAYS
She has the best hair of any Crash Course host, WAAAAAAAAY better than Craig from Crash Course politics.
+Aaron Horrell What about Phil Plait
Too bad this was posted after the AP Physics Mechanics test! Still a great video and I am happy that Crash Course isn't afraid of covering a math heavy subject like physics.
Everything in this one made sense! I think I'm learning things.
man, you guys should have done this last year, it's literally perfect for AP physics review.
please make crash course programming
That'd be a dream. But VERY LONG
+
YES
+
We now have Crash Course Computer Science. That's pretty good
time to re-watch this 5 more times
"I'm getting dizzy just think about it"
She said as she cut to a graphic of SPINNING GEARS.
Homegirl in the video is really beautiful and very well spoken
+Harmony of Nature almost distracting
+Harmony of Nature Dr. Shini Somara... I believe she's Indian.
Hi this video was so amazing keep up the good work love you all so much
You videos have helped me so much in Physics. I couldn't find any reliable, informative and yet interesting video like these ones. I can't thank you enough. I'm more than thankful to you. 😊😊😇😇
Didn't understand anything, sugar still gathers in the center of my tea cup.
That would be due to centripetal motion (a force going towards the center of rotation). The only difference is that the system is more complex.
When you stir the cup, water is forced outward because of centrifugal force, the same sensation you get when riding a carousel. This makes the pressure higher towards the edge of the cup. Close to the bottom of the cup friction between the fluid and the cup forces the swirling motion of the water to slow down and this in turn makes it possible for the pressure difference to establish a current towards the center of the cup that is stronger than the centrifugal force.
@@samsonclement7604 I thought she said centrifugal force doesn't exist
"So engineers tested potential astronauts by putting them in a human centipede."
Best channel for physics
That was a lot of math, but I think I got it. Also Shini is beautiful.
This video explained Uniform Circular Motion in nearly ten minutes better than my teacher in almost a week. Thank You!
after having no idea what’s been going on in physics for a week and having a test on this tomorrow, it just made complete sense.
thank you thank you for the visual representation! (color coding the variables / connecting the variables with a line was also a nice touch :) )
I was whating for this one for a while
+Alexis Trodglen Hope you enjoy it!
you were what??? whating...ok well then ...😑
+Master Max JEDI
Maybe it's shorthand for "waiting for whales"
OK I didn't know that lol
Brilliant course with this one, and a very intelligent instructor. It's well broken down, and conceptually it just makes sense in under 10 minutes.
this came at the right time to reinforce what i already knew about circular motion in a cool, graphical way for my exam tomorrow.
Thanks for this upload!
I am very please to see a woman explaining things that used to be mainly in the domain of men. Very well done young lady, my hat is off to you. BRAVO !
Your eye contact is appreciable along with your stuff...it kept me focussed.
I love how they have the ‘Feynman lectures on Physics’ on the shelves. Great books.
1:22 the editing though
Hooray for the guy who ends up cleaning up all the vomit \ o /
2:40 Or a Wii-mote, as many, many people that refused to use the wrist strap can attest.
+TalenGryphon
Except no, because in normal operation you're not spinning it in a circle. Flying Wii-motes is not a demonstration of tangential velocity, it's just throwing the thing at your tv. Agreed, though, people should use the wrist strap.
GREAT! I did you little key demonstration in my backyard, and now I've LOST my HOUSE KEY in the grass!!
Honestly, those physics videos are really helping me out! In fact, A lot :-)But you need to repeat the video and focus a lot on what Shini is saying.
Thank you so much! In our intro to uniform circular motion, we rushed through some derivations, and the concept wasn't really explained. Thank you for putting words to variables and numbers!
This so helped me. I have a circular motion test in physics tomorrow and this really saved me.
Physics aside the intro is LIT. Love this channel.
I'm so glad they've sorted out the heights of the lights behind her, it's all my brain could focus on before!
Thank you Crash Course Physics.
glad these videos are clearer now
Ahh, wish these physics topics were already finished lol, woudve helped so so much in my physics exam just like how much it has helped me in bio and chem! Found the biology 8402 igcse paper 1 so easy mostly because of CrashCourse!
screaming if i had seen this video a week ago i wouldnt have failed my physics a level lmao
I love physics and all, but her voice is beautiful
And so are her eyes.
I swear I had to replay this one 4 times just to figure out what was the difference between the analogy of the car versus the key lol. I love watching things that make me go grab a pen lol.
Dr. Shuster is a teacher at my High-school :D
?
+Riley Purcell 9:39 consultant - Dr. David Schuster
+MIQofDMC Oooohhhh. Lucky you!
Hey there, thank you guys for these awesome videos!
Overall great video and examples! thank you CC team! :)
Crash Course for the win helping me study for physics.
She taught this way better than my professors 3 hour lecture 😭
honestly these videos are the only thing saving my ap physics grade
In classical mechanics, a reactive centrifugal force forms part of an action-reaction pair with a centripetal force.
You see that sounds right but everyone keeps saying it doesn't exist. But yes in my head it's similar to the normal force
I'm studying for my senior year physics exam so I'm no expert but I'm 99.99% sure this vid is correct on the centrifugal force being a fictitious force
Not true, the action/reaction pair do *not* affect the same object: the centripetal force applied to the object is the tension force from the string, the object exerts a reaction force *on the string* , this reaction force has no interest to us since we are studying the rotating object not the string.
To realize why the Centrifugal force is not real, just examine what happens when we cut the string: there is no more Centripetal force so the object moves along a straight line that is a tangent to the circle (in the direction of the Velocity at the moment the string was cut).
If there where an actual Centrifugal force, the object should have moved in a straight radial line *perpendicular to the tangent* , which is not what happens in real life.
Centripetal force is actually a resultant force so there's no centrifugal
@@mjsaedy6637 You say:"Not true, the action/reaction pair do not affect the same object:" Of course they don't, if they did they would cancel each other out. When you swing a ball on a string your hand exert a centripetal force on the ball which reacts by exerting a centrifugal force on your hand and it is obvious these forces pass through the string. You thus have an action/reaction force pair that obeys Newton's Third Law.
I think someone lobotomized the apple at 1:00 with their teeth.
Thankyou! Khans couldn't help, my physocs teacher is useless, and this is one of the only times I actually understand what it is we're doing in that class
WTF!!! A thought y'all had this whole physics series!!! My Physics Exams Tomorrow!!
Same but my exams in an hour
Love the fact, that you took Link for the depiction! :D
My biggest crush is on an online physics teacher. Anyone else find that her looks + her knowledge is like the most attractive thing ever.
Shini could explain anything and I would listen wholeheartedly. Can we crowd fund her to record a phone alarm so I can stop hitting snooze? That, or you know... just persuade her to dub over my Discrete Mathematics professor.
my most productive 10 minutes, thank you ~
My physics mark: brought to you in part by Crash Course Physics
We're just about to start this in class, HELPED SOOO MUCH!!!
I love these videos, they're so useful for my exams! thank you!
These videos would have been so useful on Monday.
She is so good!
5:10 Isn't this simply Newton's Third Law though ?
The ride itself pushes against you so your body has an equal opposite force, this is the force that you feel pushing you against the wall...
+Lizgony That's what I was thinking
Well, Newton's 3rd Law occurs between 2 objects. Yes. The wall pushes against you while you push against the wall - the 3rd Law. But what's pushing YOU against the wall? Nothing, really. You would move in a straight line - if not for the wall pushing you toward the centre of the ride. This is why that outward force is deemed fictitious.
When you are spinning, the ride itself (the seat you're sitting on) is connected to the center, and it experiences tension force as centripetal force. You, however, aren't directly connected to the center of the ride so there is no tension force pulling you inwards. Your inertia makes you move in a straight line tangent to the circle. However, the wall of the ride is in the way, and exerts an equal and opposite force on your body, keeping you from going in a straight line, and that normal force is centripetal force for you.
So basically what you feel isn't normal force, it's your inertia. Normal force is what's keeping you on the circular path.
Neil, my friend, you deserve a cookie !
Nay! Make that TWO cookies !
:D
Lizgony No sir that's the misconception about centripetal force it doesn't exist. It feels like it but the ride isn't the reason for flying off or feeling pressed.
These videos are so informative and I love learning about it
But it super-helps that the host is amazingly beautiful and not a VlogBrother (no offense meant, I love the brothers too!)
Wow, you're' the best! Thanks for the effort you put into the vid to make it so easy to understand
These are so great to watch after going through text! Great way to reinforce the information, thank you!
Uniform circular motion is fun. Rotational dynamics, though...I could never get my head around that. I understood relativity perfectly fine, but as soon as we started discussing torque, I was so lost. It didn't help that I had a professor whose answer to "where did that equation come from" was just to write more equations on the board with little to no added explanation...
that's been my teacher pretty much all year lol.
FINALLYYY I'VE BEEN WAITING FOR THISSS
Boy, oh boy, I loved this video!
Ah.... so nice being one of 700 early viewers.Great video!
oh yeah and please do momentum and angular velocity and angular momentum pleaseeeeeeee
the link reference was so cool:).
Thanks sooo much 😢
Your videos are getting better .... although i was worried about Link could hit his fairy with the big key
The flying key broke my mirror
My mother will now kick me out of the house.....