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
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!
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 !
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. 😊😊😇😇
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 !
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...
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!
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!
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.
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
I've taken Calc, but not physics. Sometimes it's hard to wrap my head around what they're saying, I have to make sure to pay attention and visualize a lot in my head, rewinding from time to time, but in the end, it's nice to come away with a little better understanding than I had.
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.
did you just squeeze in dimension analysis at the end there? That might deserve a little more attention since it's a super usefull tool for checking any calculation you are doing. And it gets only more important the more complicated your equations get.
A spaceman in training is rotated in a seat at the end of the horizontal arm of length 5 metre. If he can withstand accelerations upto 9 g, then what is the maximum number of revolutions per second permissible? (Take g = 10 ms^-2) (A) 15.5 rev/s (B) 1.35 rev/s (C) 0.675 rev/s (D) 6.75 rev/s
She really has a clear way of explanation compared to a lecture but i feel that is from the fact that she has the time and the ability to use accurate graphics, though I also think that is why she could go at such a quick pace, though that also makes me want to see more calculus in the show, you know introduce the basic parts then get more technical and mathematical. Though maybe I am asking for too much. although I am using although and though to much.
It's important to remember that the centripetal force is really not a force in and of itself either. It's the NET force once you consider the vector sum of all the forces acting on an object moving uniformly along a circular path. Remember that, in Newtonian dynamics, it's the net force that causes an object to accelerate. Since the acceleration is centripetal, it would follow that this acceleration is directly associated with the centripetally acting NET force. Y'know?
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!)
'Centrifugal force' actually does exist. It is called fictitious because the rotating reference frame is not inertial. However the tendency of objects in a rotating reference frame to accelerate radially outwards , which is what we are calling 'centrifugal force' is very real. It isn't technically a 'force', because 'radially outwards' is not a valid vector direction in a rotating reference frame, but the phenomenon still exists, and from the rotating reference frame, it behaves exactly as a force does.
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 feel like just saying "ignore centrifugal force, it's not real" isn't particularly helpful because ,as you say, we still feel it. Actually describing why we feel it might be more useful in explaining why it's not real and that it's just your intertia and all that jazz!
I can't help but feel that Physics isn't best suited for a video format like this. If I didn't know about circular motion already I'd find it pretty difficult to keep up. That being said, this video does very well!
+Tim James you didn't have your teacher go "trust me, velocity is tangential, net force is inwards, and the only equation that makes any sense(this was before the class knew calculus) is v=x/t"? i think that they're finally finding their feet with this format, although i would like to see a demonstration, and all that maths in the beginning was enough to confuse everyone, and you need to watch ALL the videos, as this one covered frames of reference...
+CrashCourse Small tip. The editing is too fast. You are not giving the viewers any time to take in what they just heard before going into the next sentence or point. Leave a small breather. Just a second may be enough. Don't rush things, especially with scientific subjects like this one.
j26walker The things I have listed have little to do with actual crash courses and more with video editing. Many videos, especially on youtube, are edited poorly and way to quickly with awkward pace shifts. Giving small breathers helps the viewers digest what they just saw and heard. And keeping a proper pace and changing it at the right moments also helps with conveying information and mood. This applies not only to educational videos, but movies and everything else as well. An appropriate rhythm is important. That's the difference between the Transformers bad edits and the Avengers great ones. ;) That said, Crash Course usually does a very decent editing job. This video was way too quick paced though.
I have a tricky question i was never able to answer: assuming 1) if you have more and less massive objects affected by centrifugal force, the more massive will tend to spread in the outer part and the less massive will tend to stay to the center 2) if u put rice in a pot it'll go down because is heavier (that's how it is) why the heck if you stir in a pot with rice in it stays in the middle? isn't it actually centrifugal force? does it depend on the resistence of the water? is rice magic?
+colox97 2 quick layman's ideas 1. assume that the rice is a liquid layer underneath the water with identical properties. as the rice is underneath the water, first thing we need to do is remove / reduce the amount of water above the rice, and that requires a lot of motion. 2. the time for 1 revolution in the pot is constant, radius increases as we move outward from the center, let c=pi*r*r, T be the period. v=c/T consider the rice grain in the center, r=0, v=0. the rice grain in the center does not move, similar for other grains in the middle, but this approach does assume constant motion in a straight line... also, i wanna get the update when the video gets posted, so i can try a serious solution :)
+colox97 I am thinking it has to do with the fact that the rice itself is not a fluid. The rice will slow down the water when you stop stirring and vice versa, since the water is already moving slower in the center the rice will find the most balance in the center. I realize the theory isn't perfect and I am starting to find some holes in it. One experiment you could do is to use two fluids (e.g. Oil and water.) Or use fluids with different temperatures since the water will heat up faster then the rice. Good luck looking for an answer.
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.
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
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
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
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!
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)
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).
currently watching this 3 hours before my AP test. god bless your soul
You spin me right round... Thank you for your time.
😂 nice one 😂
Bless you guys, this has practically saved my GPA. So much easier to understand than what's taught in school
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.
"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 😃😅
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
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!
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 !
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
I'm in university physics and these videos are incredibly helpful! Thank you
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.
Circular motion was my favorite section of physics last year, awesome video!
The key turning 'experiment' is basically how discus throwers don't knock out anyone standing beside/behind them.
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
2:47 Oh hi there, Link! How are you?
@Dr. Shini Somara
You're just the whole package. I could listen to you could talk physics for hours. :)
She has the best hair of any Crash Course host, WAAAAAAAAY better than Craig from Crash Course politics.
+Aaron Horrell What about Phil Plait
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 :)
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.
CRASH COURSE IS IMPORTANT ALWAYS
man, you guys should have done this last year, it's literally perfect for AP physics review.
1:21
I was pretty concentrated on the video and thought I was just about to pass out.
Well played. 10/10.
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.
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. 😊😊😇😇
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.
That was a lot of math, but I think I got it. Also Shini is beautiful.
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 !
This video explained Uniform Circular Motion in nearly ten minutes better than my teacher in almost a week. 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.
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.
I love physics and all, but her voice is beautiful
And so are her eyes.
1:22 the editing though
This so helped me. I have a circular motion test in physics tomorrow and this really saved me.
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!
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.
I love how they have the ‘Feynman lectures on Physics’ on the shelves. Great books.
She is so good!
Best channel for physics
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.
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!
thank you thank you for the visual representation! (color coding the variables / connecting the variables with a line was also a nice touch :) )
WTF!!! A thought y'all had this whole physics series!!! My Physics Exams Tomorrow!!
Same but my exams in an hour
Your eye contact is appreciable along with your stuff...it kept me focussed.
Dr. Shuster is a teacher at my High-school :D
?
+Riley Purcell 9:39 consultant - Dr. David Schuster
+MIQofDMC Oooohhhh. Lucky you!
I'm so glad they've sorted out the heights of the lights behind her, it's all my brain could focus on before!
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.
My biggest crush is on an online physics teacher. Anyone else find that her looks + her knowledge is like the most attractive thing ever.
Hi this video was so amazing keep up the good work love you all so much
glad these videos are clearer now
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.
honestly these videos are the only thing saving my ap physics grade
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
I've taken Calc, but not physics. Sometimes it's hard to wrap my head around what they're saying, I have to make sure to pay attention and visualize a lot in my head, rewinding from time to time, but in the end, it's nice to come away with a little better understanding than I had.
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.
did you just squeeze in dimension analysis at the end there? That might deserve a little more attention since it's a super usefull tool for checking any calculation you are doing. And it gets only more important the more complicated your equations get.
These videos would have been so useful on Monday.
Crash Course for the win helping me study for physics.
A spaceman in training is rotated in a seat at the end of the horizontal arm of length 5 metre. If he can withstand accelerations upto 9 g, then what is the maximum number of revolutions per second permissible? (Take g = 10 ms^-2)
(A) 15.5 rev/s
(B) 1.35 rev/s
(C) 0.675 rev/s
(D) 6.75 rev/s
Love the fact, that you took Link for the depiction! :D
Physics aside the intro is LIT. Love this channel.
She really has a clear way of explanation compared to a lecture but i feel that is from the fact that she has the time and the ability to use accurate graphics, though I also think that is why she could go at such a quick pace, though that also makes me want to see more calculus in the show, you know introduce the basic parts then get more technical and mathematical. Though maybe I am asking for too much. although I am using although and though to much.
GREAT! I did you little key demonstration in my backyard, and now I've LOST my HOUSE KEY in the grass!!
She taught this way better than my professors 3 hour lecture 😭
oh yeah and please do momentum and angular velocity and angular momentum pleaseeeeeeee
We're just about to start this in class, HELPED SOOO MUCH!!!
My physics mark: brought to you in part by Crash Course Physics
It's important to remember that the centripetal force is really not a force in and of itself either. It's the NET force once you consider the vector sum of all the forces acting on an object moving uniformly along a circular path. Remember that, in Newtonian dynamics, it's the net force that causes an object to accelerate. Since the acceleration is centripetal, it would follow that this acceleration is directly associated with the centripetally acting NET force. Y'know?
my most productive 10 minutes, thank you ~
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!)
Hey there, thank you guys for these awesome videos!
Centrifugal force is true, sometimes. For example, on one of the big swings in fairs. it moves you around in a circle, and you get pushed out.
'Centrifugal force' actually does exist. It is called fictitious because the rotating reference frame is not inertial. However the tendency of objects in a rotating reference frame to accelerate radially outwards , which is what we are calling 'centrifugal force' is very real. It isn't technically a 'force', because 'radially outwards' is not a valid vector direction in a rotating reference frame, but the phenomenon still exists, and from the rotating reference frame, it behaves exactly as a force does.
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.
Your videos are getting better .... although i was worried about Link could hit his fairy with the big key
Boy, oh boy, I loved this video!
Thank you Crash Course Physics.
I'm in love. .... with science. ;-)
Hooray for the guy who ends up cleaning up all the vomit \ o /
i feel like just saying "ignore centrifugal force, it's not real" isn't particularly helpful because ,as you say, we still feel it. Actually describing why we feel it might be more useful in explaining why it's not real and that it's just your intertia and all that jazz!
I am looking forward to the explanation for the Gravitational constant.
I can't help but feel that Physics isn't best suited for a video format like this. If I didn't know about circular motion already I'd find it pretty difficult to keep up. That being said, this video does very well!
+Tim James I didn't know how circular motion worked, but this video explained it quite clearly.
+Tim James you didn't have your teacher go "trust me, velocity is tangential, net force is inwards, and the only equation that makes any sense(this was before the class knew calculus) is v=x/t"?
i think that they're finally finding their feet with this format, although i would like to see a demonstration, and all that maths in the beginning was enough to confuse everyone, and you need to watch ALL the videos, as this one covered frames of reference...
+CrashCourse
Small tip.
The editing is too fast. You are not giving the viewers any time to take in what they just heard before going into the next sentence or point. Leave a small breather. Just a second may be enough. Don't rush things, especially with scientific subjects like this one.
It's called crash course for a reason.
j26walker The things I have listed have little to do with actual crash courses and more with video editing.
Many videos, especially on youtube, are edited poorly and way to quickly with awkward pace shifts.
Giving small breathers helps the viewers digest what they just saw and heard. And keeping a proper pace and changing it at the right moments also helps with conveying information and mood.
This applies not only to educational videos, but movies and everything else as well.
An appropriate rhythm is important. That's the difference between the Transformers bad edits and the Avengers great ones. ;)
That said, Crash Course usually does a very decent editing job. This video was way too quick paced though.
Takako Jin I mean you can pause the video
Jst watch it more den 1 time
If on phone, try slowing any video down to .75. It helps
Thanks sooo much 😢
I love these videos, they're so useful for my exams! thank you!
I have a tricky question i was never able to answer:
assuming
1) if you have more and less massive objects affected by centrifugal force, the more massive will tend to spread in the outer part and the less massive will tend to stay to the center
2) if u put rice in a pot it'll go down because is heavier (that's how it is)
why the heck if you stir in a pot with rice in it stays in the middle?
isn't it actually centrifugal force? does it depend on the resistence of the water? is rice magic?
+colox97 Whoa. Cool problem. How fast are you stirring? The rice is under the water but clumping in the center?!? Can you upload a video?
+colox97
2 quick layman's ideas
1. assume that the rice is a liquid layer underneath the water with identical properties.
as the rice is underneath the water, first thing we need to do is remove / reduce the amount of water above the rice, and that requires a lot of motion.
2. the time for 1 revolution in the pot is constant, radius increases as we move outward from the center, let c=pi*r*r, T be the period.
v=c/T
consider the rice grain in the center, r=0, v=0.
the rice grain in the center does not move, similar for other grains in the middle, but this approach does assume constant motion in a straight line...
also, i wanna get the update when the video gets posted, so i can try a serious solution :)
+colox97 I am thinking it has to do with the fact that the rice itself is not a fluid. The rice will slow down the water when you stop stirring and vice versa, since the water is already moving slower in the center the rice will find the most balance in the center.
I realize the theory isn't perfect and I am starting to find some holes in it.
One experiment you could do is to use two fluids (e.g. Oil and water.) Or use fluids with different temperatures since the water will heat up faster then the rice.
Good luck looking for an answer.