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
Hey Crash Course I was wondering if you guys could maybe start a series on music theory. It would be nice to have for musicians wanting to improve their work. It could cover topics such as chord progression, scales, Minor/Major...etc. If you read this comment please consider, and thanks for taking the time to read it. Keep up the good work.
There's a book called 'The Theory of Sound' by Baron J.W.S. Rayleigh and the first chapter of vol I is all about musical notes and the ratio relations between them. pdf available upon a googling and it's well interesting
Studying with RUclips is easier than trying to sit through class. If I don't catch something I can always go back and rewatch it and better understand. Whereas in a classroom I'm left numb from not catching everything and hence don't learn a damned thing. Thank you for your videos they are much appreciated.
me: im going to read my barron's book for physics me instead: watches physics crash course while debating making brownies update: i made the brownies and will be giving them to my classmates tomorrow
how is it that i can have a teacher tell me something for an entire semester but won't understand it until i watch a 10 minute crash course video? i'm killing this physics final today!
Another great episode! Seriously don't understand how people can find these incomprehensible. You can't dumb it down much more, if you actually want to learn something.
Hey +CrashCourse, after this series is done, will you guys make a Crash Course about the Modern Physics (Quantum)? Pretty Please? I hope there's math too...
2:20 - 2:31 = U said impulse is the "integral of the net force on an object over time", but then added "in other words- it's change in momentum". I'm confused. I thought force was change momentum (d(mv)/dt). How can impulse, which is the integral of force, also be a measure of change in momentum?
We have slow-comprehending brains (in that it takes our brain longer to translate what our ears are hearing) (autism) so the video "words" were too fast for us to comprehend but the photos / examples were GREAT!
7:40 more like 2/3 of the distance between the centers of the balls, not the stick (assuming the stick itself is massless). This might not be significant for a long enough stick and balanced balls, but it's significant when calculating a more skewed system. Like the center of mass of a solar system (which can be inside its star or very near its surface).
The ball equation on when the ball hits the wall and changes its force in half a second. The equation itself was correct but the answer is 3.125. This is important for people taking the AP Physics C test, for they need you to round to the nearest 3 decimals.
What's the difference between inertia and momentum? Those words both mean the tendency of object to stay in motion, right? Don't they both have the same equation too?
Not really. Inertia has unique equations for different shapes (mostly variations of I =mr^2, such as I=2/5mr^2 for a solid sphere) while momentum has just the one (p=mv). The units for inertia are kgm^2 and the units for momentum are kgm/s. Inertia is a property of an object where it resists a change in motion, whereas momentum is just a statement of the velocity and mass of that object.
I don't know who you are and I don't like the fact that you're not John or Hank Green but I will live with it since you have the most gorgeous accent I've ever heard
I would really enjoy a series in which you guys talk about culturally significant music, from pop culture to the classics. I often feel like uncultured swine when a song comes on the radio that I don't know and everyone else seems to think it is iconic.
thank you!!! thank you for helping me to find the joy of learning this! (instead of just memorizing useless formulas that I don't get where did those derive from!)
you said in your video on newton's laws that according to newton's first law, an object would remain stationary (or in constant movement) unless acted upon by a force. A moving object that has momentum is moving at a constant velocity and thus has no acceleration, ergo should not be able to exert a force. However, that rolling ball is obviously able to move indiana jones if it collides with him. How is that?
Can elastic collisions occur in a vacuum? This seems to make sense because there aren't any particles to make friction. For example, if one object were to crash into a stationary object of equal mass, then all the energy should transfer into the stationary object and send it moving at the same speed as the first object was originally.
But there is compression, AKA sound within solid objects, or deformation, both of which turns into heat (try bending a spoon, it will get hot, it's internal friction between the molecules of metal in the spoon). And who said there is no friction? There might not be any with the vacuum, but between the objects, why not?
At 6:00 she states that the momentum is conserved but some kinetic energy is lost because the now stuck together magnets are traveling slower than the single magnet. Where did the kinetic energy go? I thought this was a perfectly inelastic collision in which--theoretically speaking--no energy is lost to thermal energy. If momentum is perfectly conserved, isn't kinetic energy also conserved since it equals 0.5mv^2? Am I misunderstanding something? Great video overall, thanks for posting!
Energy and momentum are different quantities! Momentum will always be conserved, whereas (kinetic) energy will often be lost. I understand your confusion though; the equations for momentum and kinetic energy look similar.
In elastic collisions, no energy is lost. In inelastic collisions, energy is *always* lost. For the magnets, most of that is sound, but also some heat. The mass goes up, the velocity goes down, and the momentum (mv) balances out, but energy weights velocity disproportionately (.5mv^2), so it's lost.
This lady is amazing. Wish she taught at my college. Would have done much better in Calculus and Physics in college and became a scientist instead of a lawyer . . . . plus she's got to be the best looking Physicist I've ever seen :-)
@@user-nd1lx8co2g So just because a female has a career in STEM, she MUST be proving a point and furthering the feminist agenda instead of just pursuing something she's genuinely passionate about? Good to see misogyny is still alive and well.
@@user-nd1lx8co2g But when Hank and John read from scripts it's no big deal right? They're not fake just because they're males? Okay, whatever you say.
Something's a little off here. She says impulse is change in momentum over time, but that would be mv/t, which is the same thing as ma, which is just force. Impulse is mv/t^2, or ma/t, or force per time.
Impulse is *just* change in momentum, and it's force*time. It has the same units as momentum (kg*m/s). It's the amount of momentum lost or gained. *Force* is change in momentum over time (kg*m/s^2)
You're right, I was confusing impulse with jerk, which is acceleration per time. Force per time is equal to mass times jerk, and may or may not be called yank; I can't find a reliable source confirming that.
I actually find it easier to say that the centre of mass is the first moment of the mass distribution. Momentum is not conserved in systems with drag (or other forms of friction). Not to mention that in the examples with the magnets, they will accelerate towards each other and even then you will not have conservation of momentum. Even if one is inclined to perform this little experiment it will be quickly realised that the magnetic bead pair will most likely start spinning after it comes together.
Momentum is conserved in systems with drag -- the momentum is simply transferred to the thing doing the dragging. If you're talking about air resistance, then momentum is transferred from the moving object to the air. If you're talking about friction, then the momentum is transferred from the moving object to the surface which is creating the friction. Often the momentum will end up getting transferred to the Earth, which will result in the momentum apparently disappearing -- but it hasn't disappeared, it's just that the Earth's mass is so large that any resulting velocity change is minuscule.
If the position of a body moving in a medium is monitored then momentum is not conserved, categorically. Furthermore momentum doesn't have to be conserved in situations where you do not have spatial translation symmetry. In addition to non conservative systems as noted above. In short to force momentum conservation you have to redefine the 'system' to include much more than one might have originally intended. The case is still true for interacting particles, where momentum is, simply, not conserved.
Jason93609 You are being misleading. When physicists say that momentum is conserved, they mean it is conserved in a closed system i.e. where there are no interactions between your system and the outside world. This is *always* true, from the scale of galaxies, right down to sub-atomic particles. There are no known exceptions to this rule. You are talking about open systems, where the changes in momentum are not being wholly accounted for -- momentum is not conserved in that case, but then no-one ever claimed it was. (This holds true for energy too -- it is only conserved in a closed system.)
Wait, in the example with the magnets, the mass doubled, so the velocity was cut in half (which means its kinetic energy is cut in a quarter), so momentum is conserved. But you said some of the kinetic energy is lost (not literally). But that means that half of the kinetic energy is lost, how can so uch energy be lost every time such a collision happens?
Linear Momentum and Angular Momentum are very similar both are 'Vector' quantities, except with 'Angular Momentum' the vector is constantly changing, there is only an 'instantaneous' vector at any particular subtended angle of rotation. Sir Isaac Newton was correct about 'Actions and Equal and Opposite Reactions", but only in simple cases. Sometimes the word 'Opposite' can be turned around. For example we have two parallel tracks, each with a truck in linear motion. They both collide simultaneously with two mirror image discs. ...and just like the linear experiment Momentum is conserved by transfer of linear kinetic energy via two mirror image 'Elastic Collisions' into equal 'mirror image' counter-rotational Angular Momentum. ...These discs are equipped with magnetic bounce mechanisms like the trucks, [near 100% elastic bounce] they bounce back and return their 'Angular Momentum; with a third 'magnetic bounce' to the pair of parallel track trucks. The trucks have effectively "Bounced Back", but it will be observed in practice and reality, that there has been no measurable reaction at all. If this experiment is conducted on a small toy boat, the boat will keep going forward with each elastic bounce, but never go backwards. "VECTORS! MATTER" and please never forget that essential face, especially with a' Vector Quantity' like Momentum.
In Russian momentum is called "impulse" and "impulse" is called "force impulse". It got me confused at the beginning, because every time I hear "impulse" I think of the momentum.
I really like this series, you are all doing a brilliant job on the topics, animation, presentation and so on :D Only thing is that she talks a bit slow but that's ok cause we have the 2x speed option ^^
I wish they had a 10x speed but that probably still wouldn't be fast enough for me. If she's going too slow then you guys should probably move on to a video that's more involved because this is just a sliver of how involved physics can get.
Dear Madam, There is a question which is iching my taughts since many days, that why speed of sound is constant??? Even though sound propagate by means of elastic collisions between molecules, speed of sound should depend upon the speed of molecules near the source of sound. Yes I have heard it already that molecule speed is directly proportion with the increase in pressure so the bulks module remains constant and hence the formula holds. But why then same phenomena is not observed in collision of two identical elastic balls, were the velocity of second ball depends upon the velocity of the first ball and hence the velocity of propagation of this collision also depended on the velocity of first.
So if the perfectly inelastic collision of the magnets always ends with M = 2m and V = 1/2 v, does that mean that 2 * 1/4 = 1/2 of the kinetic energy is always expressed in the form of sound or heat?
For the magnets yes, that's why they make a loud "clack" when they hit. For softer things, most of the energy is used to deform the objects, and they make a much smaller sound.
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
Hey Crash Course
I was wondering if you guys could maybe start a series on music theory. It would be nice to have for musicians wanting to improve their work. It could cover topics such as chord progression, scales, Minor/Major...etc.
If you read this comment please consider, and thanks for taking the time to read it. Keep up the good work.
Totally yes, same here i need music theory too.
Yes pleaseee!! I'm certain many people will benefit from this too!
There's a book called 'The Theory of Sound' by Baron J.W.S. Rayleigh and the first chapter of vol I is all about musical notes and the ratio relations between them. pdf available upon a googling and it's well interesting
YES best idea I’ve ever heard on RUclips
She speaks so flawlessly!! And clearly !!! She can simplify even the hardest of the topics !!!
Studying with RUclips is easier than trying to sit through class. If I don't catch something I can always go back and rewatch it and better understand. Whereas in a classroom I'm left numb from not catching everything and hence don't learn a damned thing. Thank you for your videos they are much appreciated.
How do I manage to hate school so much, yet still watch every Crash Course video?
No homework?
+Matthew Kessler but homework is important so we can apply what we learned.
You aren't forced to think too heavily about the topics at times you don't want to.
Because school offers so many boring physics topics and boring ways to learn them.
Try to ask your teachers questions about things you learned here at crash course and which you wanna learn more about.
me: im going to read my barron's book for physics
me instead: watches physics crash course while debating making brownies
update: i made the brownies and will be giving them to my classmates tomorrow
S😝
This was uploaded...
...the day after my physics exam...
F
Copy cat
F
dont copy.
sorry man
Collision Course Physics
How did this not occur to ANYONE else??? Hats off to you.
-Nick J.
I do not understand can you please explain to me
The Commentator f
they should change the playlist name
crash = collision
crash course = collision course
The day has finally come when CRASHCOURSE does a video on collisions!!! :)
Speedy thing goes in, Speedy thing comes out.
👍
👍
You can't explain that!
ooh now I want to play portal 2 all over again. Don't help me procrastinate ;p.
i understand the portal reference, but I don't know why I first read this in cgp grey's voice
Just took my physics final today. these videos were really helpful to review with. 😊
Great!
-Nick J.
*Is just watching due to nerdism*
You might have to wait to see if that statement is true or false.
+Overkillermark2 Bruh!! :)
+MegaFarinato I say they were. I got an 89!!! 😁
Yes, yes.. mmhm
I understand...
some of these words
😂
I can pretty much relate...
i relate so much =D
Just watch it like 4 times u’ll get it, dat what I did
how is it that i can have a teacher tell me something for an entire semester but won't understand it until i watch a 10 minute crash course video? i'm killing this physics final today!
This speaker has like the perfect voice for explaining things on the internet
Another great episode! Seriously don't understand how people can find these incomprehensible. You can't dumb it down much more, if you actually want to learn something.
I'm literally in love with this host. She's the best one in teaching physics.
Can't wait until we start discussing electricity and electric circuits! These physics episodes are the highlight of my Fridays :D
So beautiful gradients at the end! Great job as always graphics team :D
Please fix that rubix cube, it's driving me insane.
Esoteric Botanist dunno, but yeah
yeah me to i do not like it
it is meant to be that way
Ocd
o my gosh yess me tooooo
"every action has and equal and opposite reaction."
-except when we both start rappin!-
mgk vs eminem
im satisfied with your pun, its non-stop. You have no idea how long i've waited for this.
Isaac Newton v bill nye
I’ve accelerated the mind of mankind
The integral sec y dy from 0 to 1/6 of π is log to base e of √3 times the 64th power of what?
This video helped me understand this concept just in time for the physics subject test this Saturday! All the love, crash course. xoxo
Woohoo!
-Nick J.
Hey +CrashCourse, after this series is done, will you guys make a Crash Course about the Modern Physics (Quantum)? Pretty Please? I hope there's math too...
*"Momentum, the Product of Mass and Velocity is conserved between portals. In Laymen's terms, Speedy thing goes in, Speedy thing comes out."*
Fivestrings uuuuh
2:20 - 2:31 = U said impulse is the "integral of the net force on an object over time", but then added "in other words- it's change in momentum". I'm confused. I thought force was change momentum (d(mv)/dt). How can impulse, which is the integral of force, also be a measure of change in momentum?
We have slow-comprehending brains (in that it takes our brain longer to translate what our ears are hearing) (autism) so the video "words" were too fast for us to comprehend but the photos / examples were GREAT!
7:40 more like 2/3 of the distance between the centers of the balls, not the stick (assuming the stick itself is massless). This might not be significant for a long enough stick and balanced balls, but it's significant when calculating a more skewed system. Like the center of mass of a solar system (which can be inside its star or very near its surface).
Crash course is the best series ever.
yes queen
She's pretty
+Allen Jasper Her eyes are hypnotic!
Nori Stockholm's syndrome is tragic
I honestly though she said a bag of bees rolling down a hill that would be easy to stop.
NOTE DO NOT ATTEMPT TO STOP A BAG OF BEES WITH BEAR HANDS.
mozayeniml LEAVES not bees
Bears. eat. beets
The ball equation on when the ball hits the wall and changes its force in half a second. The equation itself was correct but the answer is 3.125. This is important for people taking the AP Physics C test, for they need you to round to the nearest 3 decimals.
What's the difference between inertia and momentum? Those words both mean the tendency of object to stay in motion, right? Don't they both have the same equation too?
Not really. Inertia has unique equations for different shapes (mostly variations of I =mr^2, such as I=2/5mr^2 for a solid sphere) while momentum has just the one (p=mv). The units for inertia are kgm^2 and the units for momentum are kgm/s. Inertia is a property of an object where it resists a change in motion, whereas momentum is just a statement of the velocity and mass of that object.
Taylor Arch Thank you for your answer!
You can't change inertia, but you can change momentum.
Assume mass is conserved.
WebGuy1000 - Domino Entertainment X-Men be fggcfff
WebGuy1000 - Domino Entertainment X-Men be fggcfff
Indiana Jones died just so we could learn about momentum. We must ace our physics tests to not let his death go in vain
1:48
i really expected that cat to yowl and fly away from the bag of leaves
shoutout to all the AP physics students who think they will understand all the concepts the night before the exam through crash course
I don't know who you are and I don't like the fact that you're not John or Hank Green but I will live with it since you have the most gorgeous accent I've ever heard
Big love from everyone revising for M1 in England!!
Brilliant work and explained very well🫶
I"m surprised by how much I learned from this video.
Finally! A video I found an actual use for making legitimate use for RUclips's slow-down feature rather than only making people sound drunk. 😁
I was hoping that it would be my favorite narrator when clicking this on the video. Luckily it was, which means my day is off to a good start
I would really enjoy a series in which you guys talk about culturally significant music, from pop culture to the classics. I often feel like uncultured swine when a song comes on the radio that I don't know and everyone else seems to think it is iconic.
In Highschool, Kenya, we call it the Centre of Gravity, not mass. Not much of a difference, but it shows how different our curriculum is.
Perfectly inelastic?? UGH, ECONOMICS!
Miles Quickster BRUH
This video taught me more about collisions than what my teacher has in the past 2 weeks.
This is a great video!! Thank you!! Also love how the pool table scenes have that background noise. So creative!! Haha!!
I was stressing so much about 9 mins and 20 seconds ago, these videos are such great review tools!!
thank you!!! thank you for helping me to find the joy of learning this! (instead of just memorizing useless formulas that I don't get where did those derive from!)
you said in your video on newton's laws that according to newton's first law, an object would remain stationary (or in constant movement) unless acted upon by a force. A moving object that has momentum is moving at a constant velocity and thus has no acceleration, ergo should not be able to exert a force. However, that rolling ball is obviously able to move indiana jones if it collides with him. How is that?
came fo the knowledge stayed 4 the backgrounds, really love the animation guys , .......gr8 movez...... keep it up.
Thank You so much Crash Course
I love this teacher so much
Enjoyed your contribution to the programme about the battle of jutland on the bbc, shini. Very interesting.
Really liking CCP, too.
marvellous video
I am literally in love with this person.
Can elastic collisions occur in a vacuum? This seems to make sense because there aren't any particles to make friction. For example, if one object were to crash into a stationary object of equal mass, then all the energy should transfer into the stationary object and send it moving at the same speed as the first object was originally.
No - some energy is converted into heat. Sound is just one of the ways for energy to disperse.
+animowany111 but no energy is converted to heat because there is no friction. Right?
But there is compression, AKA sound within solid objects, or deformation, both of which turns into heat (try bending a spoon, it will get hot, it's internal friction between the molecules of metal in the spoon).
And who said there is no friction? There might not be any with the vacuum, but between the objects, why not?
+animowany111 good point. Thanks for the explanation!
Where does the 25 come from in the impulse equation at 2:44? I understand it is an integral over .5 seconds but where does 25 come from?
thanks!
Taking my physics final in like 7 minutes
Love the Indiana Jones joke they used. Crash Course you're so amazing.
3:27 How do you know if the white ball would bounce off the red ball or stay put after it hits the red ball?
what a helpful video!!! thanks for the knowledge crash course
At 6:00 she states that the momentum is conserved but some kinetic energy is lost because the now stuck together magnets are traveling slower than the single magnet. Where did the kinetic energy go? I thought this was a perfectly inelastic collision in which--theoretically speaking--no energy is lost to thermal energy. If momentum is perfectly conserved, isn't kinetic energy also conserved since it equals 0.5mv^2? Am I misunderstanding something? Great video overall, thanks for posting!
Energy and momentum are different quantities! Momentum will always be conserved, whereas (kinetic) energy will often be lost. I understand your confusion though; the equations for momentum and kinetic energy look similar.
In elastic collisions, no energy is lost. In inelastic collisions, energy is *always* lost. For the magnets, most of that is sound, but also some heat. The mass goes up, the velocity goes down, and the momentum (mv) balances out, but energy weights velocity disproportionately (.5mv^2), so it's lost.
This lady is amazing. Wish she taught at my college. Would have done much better in Calculus and Physics in college and became a scientist instead of a lawyer . . . . plus she's got to be the best looking Physicist I've ever seen :-)
she's reading a script honestly I find her a bit distracting trying to prove a point about female physicists or something. THERE I SAID IT :P
she is ugly
@@user-nd1lx8co2g So just because a female has a career in STEM, she MUST be proving a point and furthering the feminist agenda instead of just pursuing something she's genuinely passionate about? Good to see misogyny is still alive and well.
no it's just that everything about this is fake she is reading from a script @@sarahholland5980
@@user-nd1lx8co2g But when Hank and John read from scripts it's no big deal right? They're not fake just because they're males? Okay, whatever you say.
1:15, *F* = m(d *v* )/dt = m(d *a* t)/dt = m *a*
Arwildo thats only gonna work if a is constant
brains and beauty.
These videos are so helpful and save so much time!
i owe you my life! these videos rock
awesome episode!!!Very informative
My science test is on Tuesday... please finish the series before then!!!
That would be amazing for my revision :)
If tendency of an object to remain in motion is called momentum, isn't it sorta similar to inertia??
Inertia is the tendency of an object to remain in motion or rest while momentum is the tendency of an object to remain in motion :)
think of momentum as a special case of inertia
Momentum is inertia at a certain point when collision happens.
So wait, force is the derivative of mass times velocity, a.K.a momentum relative to time. Mind Blown
Something's a little off here. She says impulse is change in momentum over time, but that would be mv/t, which is the same thing as ma, which is just force. Impulse is mv/t^2, or ma/t, or force per time.
Impulse is *just* change in momentum, and it's force*time. It has the same units as momentum (kg*m/s). It's the amount of momentum lost or gained.
*Force* is change in momentum over time (kg*m/s^2)
You're right, I was confusing impulse with jerk, which is acceleration per time. Force per time is equal to mass times jerk, and may or may not be called yank; I can't find a reliable source confirming that.
Is kinetic energy derived from the integral of momentum? 1/2 V^2 looks like an antiderivitive.
I actually find it easier to say that the centre of mass is the first moment of the mass distribution.
Momentum is not conserved in systems with drag (or other forms of friction).
Not to mention that in the examples with the magnets, they will accelerate towards each other and even then you will not have conservation of momentum. Even if one is inclined to perform this little experiment it will be quickly realised that the magnetic bead pair will most likely start spinning after it comes together.
lol
Momentum is conserved in systems with drag -- the momentum is simply transferred to the thing doing the dragging. If you're talking about air resistance, then momentum is transferred from the moving object to the air. If you're talking about friction, then the momentum is transferred from the moving object to the surface which is creating the friction. Often the momentum will end up getting transferred to the Earth, which will result in the momentum apparently disappearing -- but it hasn't disappeared, it's just that the Earth's mass is so large that any resulting velocity change is minuscule.
If the position of a body moving in a medium is monitored then momentum is not conserved, categorically.
Furthermore momentum doesn't have to be conserved in situations where you do not have spatial translation symmetry. In addition to non conservative systems as noted above.
In short to force momentum conservation you have to redefine the 'system' to include much more than one might have originally intended.
The case is still true for interacting particles, where momentum is, simply, not conserved.
Jason93609
You are being misleading. When physicists say that momentum is conserved, they mean it is conserved in a closed system i.e. where there are no interactions between your system and the outside world. This is *always* true, from the scale of galaxies, right down to sub-atomic particles. There are no known exceptions to this rule. You are talking about open systems, where the changes in momentum are not being wholly accounted for -- momentum is not conserved in that case, but then no-one ever claimed it was. (This holds true for energy too -- it is only conserved in a closed system.)
"Closed" systems are very special! And not the most relevant as well.
definitely gonna watch all ur vids this saturday lmao
woah, you uploading this right the before i have a test about collisions is amazing (for me)
Can anybody please explain the math at 2:37? :)
Sir Newton, what a fascinating man
Why would velocity get halved as mass doubles in the magnet example? Mass and velocity are directly proportional?
Unique content! I found no better.
i love the way you explain
love it. thanks
Wait, in the example with the magnets, the mass doubled, so the velocity was cut in half (which means its kinetic energy is cut in a quarter), so momentum is conserved. But you said some of the kinetic energy is lost (not literally). But that means that half of the kinetic energy is lost, how can so uch energy be lost every time such a collision happens?
thank you for the video!
Literally so helpful
Linear Momentum and Angular Momentum are very similar both are 'Vector' quantities, except with 'Angular Momentum' the vector is constantly changing, there is only an 'instantaneous' vector at any particular subtended angle of rotation. Sir Isaac Newton was correct about 'Actions and Equal and Opposite Reactions", but only in simple cases. Sometimes the word 'Opposite' can be turned around. For example we have two parallel tracks, each with a truck in linear motion. They both collide simultaneously with two mirror image discs. ...and just like the linear experiment Momentum is conserved by transfer of linear kinetic energy via two mirror image 'Elastic Collisions' into equal 'mirror image' counter-rotational Angular Momentum. ...These discs are equipped with magnetic bounce mechanisms like the trucks, [near 100% elastic bounce] they bounce back and return their 'Angular Momentum; with a third 'magnetic bounce' to the pair of parallel track trucks. The trucks have effectively "Bounced Back", but it will be observed in practice and reality, that there has been no measurable reaction at all. If this experiment is conducted on a small toy boat, the boat will keep going forward with each elastic bounce, but never go backwards. "VECTORS! MATTER" and please never forget that essential face, especially with a' Vector Quantity' like Momentum.
Helpfull video, thanks for your work
In Russian momentum is called "impulse" and "impulse" is called "force impulse". It got me confused at the beginning, because every time I hear "impulse" I think of the momentum.
I really like this series, you are all doing a brilliant job on the topics, animation, presentation and so on :D Only thing is that she talks a bit slow but that's ok cause we have the 2x speed option ^^
That's the first time I've ever heard someone say that a crash course presenter talks too slowly
+TheGamingWhovian I said that too! Even 2x speed is too slow.
I wish they had a 10x speed but that probably still wouldn't be fast enough for me. If she's going too slow then you guys should probably move on to a video that's more involved because this is just a sliver of how involved physics can get.
when people say 'Mario' like that, I die a little inside.
you have saved my life
Crash Course: Saver for every test.
hey thank you so much this video really helped me out!
How does an object loose energy through sound? 3:40
Love u Crash course!
The moment you learn more in 9 mins watching a youtube video than you did sitting in a class you are playing thousands of dollars for.
This might save my GPA thank you so much!!
Wish this had come out before my GCSE Physics exams.
Could an elastic collision be possible in a vacuum, where heat and sound are impossible?
Dear Madam,
There is a question which is iching my taughts since many days, that why speed of sound is constant??? Even though sound propagate by means of elastic collisions between molecules, speed of sound should depend upon the speed of molecules near the source of sound. Yes I have heard it already that molecule speed is directly proportion with the increase in pressure so the bulks module remains constant and hence the formula holds. But why then same phenomena is not observed in collision of two identical elastic balls, were the velocity of second ball depends upon the velocity of the first ball and hence the velocity of propagation of this collision also depended on the velocity of first.
Do we add the mass dist. products?
So if the perfectly inelastic collision of the magnets always ends with M = 2m and V = 1/2 v, does that mean that 2 * 1/4 = 1/2 of the kinetic energy is always expressed in the form of sound or heat?
For the magnets yes, that's why they make a loud "clack" when they hit. For softer things, most of the energy is used to deform the objects, and they make a much smaller sound.