@Ρгοηαtoг тεηdoη yup, they radiate pretty hard, slowing the speed dramatically over thousands of years. Later then they keep rotating at a slower pace much more peacefully
@Darui blackholes don't have rpm per se, but they have an angular momentum measured as a fraction of the speed of light from 0 to 1. This momentum does not correspond to an actual rotation because BH is not an object but rather a region of space-time, which twists quite oddly and counterintuitively under the influence of rotational energy
If only physics in school I went to were taught in this passionate, sweet manner I wouldve paid much more attention. Great job, Dr. Edwards. We need many more teachers like you.
but what is the point of doing this? We can easily know what was gonna happen by doing very little math. What is the point of needing a whole example to know something which can be known in 3 lines
In our school we did this experment by a one sitting on a rotatable chair giving two weights to both hands. Telling him to keep tha weights closer and with a distant time to time while rotating. Consequently his rotating speed was increased and decreased
Short version of why this works: If you think about it, both configurations have the mass moving through the same amount of space in a second. It just so happens that when it's expanded that space covers fewer degrees of rotation as the same amount of space when it's contracted does.
@@danzoom pretty much. The Earth at the equator has a surface velocity of ~460 meters per second. When experiencing this rotation on the surface, we don't feel like we are moving because we match the earth's surface velocity. TLDR: Earth's surface moves about 1000 miles per hour, we don't feel it because we are attached to it by gravity.
To anyone who wants to know the math behind this: Angular momentum dictates that a spinning object's linear velocity should remain the same even if you change its radius. According to the equation w=V/R (w being angular velocity, V is linear velocity and R is radius), as V remains constant, the larger the radius, the lower the angular velocity.
@@sombrerocat2971 no, the burden is on those who gave enough damn about any of these comment to make thier own instead of spending the same hour by doing something productive , that applies to me too :D
goddam, you're a lucky student. i went to a v v v good state school, but state schools are generally huge and due to their state funding, they tend to have more research competent profs than profs that can teach. in my 5 yr prog (at my school biotechnology and molecular biology was recommended to be finished in 5 yrs due to having 85% of our classes be lab work) we learned all of our maths (up to calc2), physics 101/102 and inorganic chemistry 101/102 by ourselves with the aid of the tutoring center. cz our maths and physics profs were on proof grants and our chem dept was on lunch cancer and stem cell research specifically and they were all trying to show results. if this dood was my physics prof I'd prolly double major in physics too. not gna lie, physical chemistry was the most difficult theoretical course I'd ever taken in undergrad.
This is also a little engineering trick to keep in mind, since this applies to gears and levers and the entire reason concepts like torque even exist. When you draw a set of circles, the bigger ones will obviously have a longer perimeter. That means that any speed going along that perimeter needs to be transferred through some form of 1 : 1 gear ratio, or you can abuse the relation between speed and distance to artificially create one in exchange for the other.
it is called the law of conservation of angular momentum. The formula for the moment of inertia for such a sphere is the product of mass x mass distribution( here the radius of the sphere ^2) times some factor( like 2/5 for a solid sphere). The angular momentum of a rotating object = the moment of inertia (denoted by I) times the angular speed. (so I x w; where w is angular speed). when the sphere contracts, the mass is still the same, but the radius decreases, hence the I decreases according to I = mass x radius^2). But since there was no external force(or rather, torque) applied, angular momentum is conserved, meaning : (I x w) final = (I x w) initial. Since I decrease in the second case, w must increase to keep equality maintained. and that is why it spins faster when contracted.
It’s such an elegant depiction of the inverse relationship. As one term in the equation gets smaller, the other increases to conserve the total amount of energy.
I know that fact for ages. Still, it was sooooo satisfying to see that presentation. And the smile on professor's face when physics worked as usual. Love science. NEver lets you down.
@@MrClubjub haha sorry MrClubjub. He was my professor at WVU before he moved to Texas! Let’s go Mountaineers! Did he still play the fiddle while riding the Unicycle when he taught your class?
My physics teacher demonstrated this by spinning on a spinny chair with his arms out holding weights, then pulling his arms in. Safe to say he was a little dizzy afterwards.
Moment of inertia is mass multiplied by square if the distance between the point and rotational axis , as u see the mass is same but the distance increases as we increase the radius.
thanks to this, it's speculated that black holes actually have donut-shaped singularities because all the rotation gets compressed into the smallest possible space, resulting in insane rotation speeds that stretch and reshape the singularity into a donut that is rotating ridiculously fast.
“donut shaped” is a stretch. They _are_ theorized to be rings, but since a ring with dimensions of 0,0,0 and a point with dimensions of 0,0,0 are indistinguishable from each other in every perceivable and measurable way except for the ring’s ability to spin.
This phenomenon is the simplest one in physics which I've never been able to intuitively understand, which makes it fascinating for me. Physically it makes perfect sense, yet it's not something I would ever come up with by myself, I don't think. Another one of those, albeit a little bit more complex, is the temperature of the air you blow out being dependant on how wide you open your mouth, not how strong you blow. I'll never forget learning that in a high school physics class, having not noticed it an any earlier point in my life. Turns out I'd been mistaking the change in the speed of the air for the cause, whereas it had also been an effect. I was amazed and couldn't stop testing it afterwards. I'd been wrong about something seemingly so natural for so long! I remember sharing this newfound knowledge with a friend, he seemed unphased about it though, "of course that's how it works" he said, more or less. Before that day, I would have said the same thing about my explanation. Goes to show how much you can miss by never investigating the "obvious" :)
For anyone wondering why it works , it is analogous to a situation in which we put a linear momentum to a rest object now suppose if its mass is reduced then it will speed up because its inertia is getting lower similarly in rotational dynamics the inertia does depnds on radius also other than its mass so if somehow we reduces its radius then its inertia decreases which results in increase in angular velocity.
Personnaly my teacher demonstrated it with a rotative chair and some weight in each hand. He start by rotating with his arm extended then he slowly put is arm closer to his body which make him spin faster.
Quick explanation for those who didnt understand: (1st ball) since I=mr2 thus if we increase the radius, moment of inertia increases. Which means moment of inertia decreases the ball's abilty to produce angular rotation. This causes a decrease in angular acceleration and thus angular velocity. (2nd ball) since I=mr2 and the radius decreased, which also decreases moment of inertia. By which the body's abilty to produce angular rotation increases. Which causes an increase in angular acceleration and thus angular velocity. Hope this helps!
Reason can be explained by the formula. L = mvr Since angular momentum(L) is conserved and mass is a constant, we have vr = constant. Hence if radius is decreases, velocity increases.
Law demonstrated, conservation of angular momentum. Now, Angular momentum (L)= Iw (I= moment of inertia, w= angular velocity) and I= (integral of two variables )MR² ( M= mass of the object, R= radius) now since Iw is conserved, (Iw) initial= (Iw) final. And since, R is reduced(also M distributed uniformly), I also decrease, but M is constant. As a result, w increases in the final result.
That smile at the end is called... Passion
Is he beta for showing emotions?
@@Breakfaststststhell no
@@Breakfastststst no, it's nice to see people teaching something they truly care about
@@Breakfastststst, man’s a gigachad for teaching cool shit
@@judgment5090 100%
This is how figure skaters spin, they tuck arms in for fast multi spins, and reach out for graceful, slow spins
Yes... now that I think about it .
@@flishry You are joking right?
@@flishry Are you joking?
@@an9l1c1sm6 I don't think he's joking
@@flishry I'd trust a person who has studied this as their specialty to be honest, aka the man in the video.
This is how neutron stars get their astonishing rotation speeds, some of them rotate at like 42000 rpm
That's ridiculous, imagine the power of the magnetic field and current that would induce
@Ρгοηαtoг тεηdoη yup, they radiate pretty hard, slowing the speed dramatically over thousands of years. Later then they keep rotating at a slower pace much more peacefully
42000 rpm? Holy vtech
what object in the universe has highest rpm? blackhole?
@Darui blackholes don't have rpm per se, but they have an angular momentum measured as a fraction of the speed of light from 0 to 1. This momentum does not correspond to an actual rotation because BH is not an object but rather a region of space-time, which twists quite oddly and counterintuitively under the influence of rotational energy
This was my college physics professor! Dr Boyd Edwards!! Guy was a legend and was a perfect example of a good, passionate professor
Mine too, go Aggies!
what school?
Thanks for sharing the professor's name
Which college do you study bro
@@rgmoses2189UC Davis
we need teachers like this
If only physics in school I went to were taught in this passionate, sweet manner I wouldve paid much more attention. Great job, Dr. Edwards. We need many more teachers like you.
If only university physics was taught like this, I wouldn't have failed
Agreed 👍🏻
but what is the point of doing this? We can easily know what was gonna happen by doing very little math. What is the point of needing a whole example to know something which can be known in 3 lines
It would help, but only by a little bit. I assume
In our school we did this experment by a one sitting on a rotatable chair giving two weights to both hands. Telling him to keep tha weights closer and with a distant time to time while rotating. Consequently his rotating speed was increased and decreased
Short version of why this works: If you think about it, both configurations have the mass moving through the same amount of space in a second. It just so happens that when it's expanded that space covers fewer degrees of rotation as the same amount of space when it's contracted does.
I like thinking about things in these ways, thanks for the brain dope
so is this also explain why the earth looks like rotating slowly?
@@sugiyonotahu that has to do with relativity. It is hard to explain and I am not an expert
@@sugiyonotahu i assume it's just because it's really big
@@danzoom pretty much. The Earth at the equator has a surface velocity of ~460 meters per second. When experiencing this rotation on the surface, we don't feel like we are moving because we match the earth's surface velocity. TLDR: Earth's surface moves about 1000 miles per hour, we don't feel it because we are attached to it by gravity.
To anyone who wants to know the math behind this:
Angular momentum dictates that a spinning object's linear velocity should remain the same even if you change its radius.
According to the equation w=V/R (w being angular velocity, V is linear velocity and R is radius), as V remains constant, the larger the radius, the lower the angular velocity.
Thanks for the equation!
@@priyadarshinibvk you're welcome :)
Thankyou,nice guy
It's amazing how much u learn when ur not forced to learn things.
Beautiful demonstration!
You can feel this when you spin in an office chair. If you tuck your legs in you spin faster than if you stuck them out.
I would enter in his class even though I am not one of his student because he deserved this kind of praise😆😆 kudos to this beloved teacher🤗🤗
I want a teacher like this one
When u know what will happeen and still enjoy more than once.....deep satisfaction
this guy was my physics professor in university.
Prove it nerd
@@georgeherbertmoonwalkerbush it is your burden to prove him wrong as the accuser
@@elijazfrazelsassafraz3100 no the burden of proof is on OP as he claimed a thing without proof.
@@James-ek3il no, burden is on nobody because this is the internet and he probably forgot he even commented about this
@@sombrerocat2971 no, the burden is on those who gave enough damn about any of these comment to make thier own instead of spending the same hour by doing something productive , that applies to me too :D
Beautiful demonstration
I love how satisfied he looks with that smile
It's awesome to see practically what we study in our books
THIS WAS MY PHYSICS PROFESSOR FROM UTAH STATE UNIVERSITY! Love this guy!
Seems like a knowledgeable and dedicated person! Nice!
👌
goddam, you're a lucky student. i went to a v v v good state school, but state schools are generally huge and due to their state funding, they tend to have more research competent profs than profs that can teach. in my 5 yr prog (at my school biotechnology and molecular biology was recommended to be finished in 5 yrs due to having 85% of our classes be lab work) we learned all of our maths (up to calc2), physics 101/102 and inorganic chemistry 101/102 by ourselves with the aid of the tutoring center. cz our maths and physics profs were on proof grants and our chem dept was on lunch cancer and stem cell research specifically and they were all trying to show results.
if this dood was my physics prof I'd prolly double major in physics too.
not gna lie, physical chemistry was the most difficult theoretical course I'd ever taken in undergrad.
This is also a little engineering trick to keep in mind, since this applies to gears and levers and the entire reason concepts like torque even exist.
When you draw a set of circles, the bigger ones will obviously have a longer perimeter. That means that any speed going along that perimeter needs to be transferred through some form of 1 : 1 gear ratio, or you can abuse the relation between speed and distance to artificially create one in exchange for the other.
"Inertia is a property of matter" - Bill Nye Intro
Moment of inertia is a property of rotating matter
Bill Nye the say whatever we pay him to guy
Inertia and moment of Inertia are different things.
That's actually a really cool demonstration of that effect, something even children could understand easily.
Hence Angular Momentum is conserved, as no external force is applied.
Isn't it Torque
Nice one short but best explaination
@@name4852 torque is done by a force but yes if you want to be precise it is torque
@@googloocraft12 But torque can still exist even though Fnet = 0
You can tell how proud he is of his example from the smile at the end, and he should be, this is a great demonstration
IW= constant so that W= constant/I , it means if I will decrease then W will increase. W= angular velocity , I= Inertia, BTW good example
Hey, thanks! Made me understand how it worked!
Is the constant=angular momentum?
@@iq_pi7211yes
The. l . W = constant
Then increase I ,decrease W.
Decrease I, increase W.
Result constant angular moment
@@iq_pi7211 yup
He is proudly follow his passion 🔥🔥💯💯
If you’d like to witness inertia in all its glory, go to a state government office
No need, I've visited a glacier before....
😂😂😂😂😂
I sure hope it keeps going
Nah. That's rather plate tectonics.
"Excuse me, where is the two hour parking for the library?"
"Is this some kind of joke?"
"Uh..?"
"You're under arrest."
Super cool demonstration. It definitely makes Moment of Inertia and Angular Momentum intuitive.
Good teachers who are passionate about what they teach are few and far between
That was satisfying af when it expanded.
Lol he was so pleased it worked 😂👍
it is called the law of conservation of angular momentum. The formula for the moment of inertia for such a sphere is the product of mass x mass distribution( here the radius of the sphere ^2) times some factor( like 2/5 for a solid sphere). The angular momentum of a rotating object = the moment of inertia (denoted by I) times the angular speed. (so I x w; where w is angular speed). when the sphere contracts, the mass is still the same, but the radius decreases, hence the I decreases according to I = mass x radius^2). But since there was no external force(or rather, torque) applied, angular momentum is conserved, meaning : (I x w) final = (I x w) initial. Since I decrease in the second case, w must increase to keep equality maintained. and that is why it spins faster when contracted.
Thankyou for Explanation
Thats the spark students need in the classroom.
That’s a great explanation of conservation of angular momentum.
This reminds me of those spinning things at the play parks
It’s such an elegant depiction of the inverse relationship. As one term in the equation gets smaller, the other increases to conserve the total amount of energy.
People with passion are the Salt of this earth.
This comment section genuinely makes me happy. People actually commenting science instead of just "oh I still can't understand, I'm so cool bs"
I know that fact for ages. Still, it was sooooo satisfying to see that presentation. And the smile on professor's face when physics worked as usual. Love science. NEver lets you down.
I literally had this exact experiment a few weeks ago in my first semester of my physic bachelor
Best explanation of conservation of angular momentum I have ever seen..
Classic demonstrasion of conservation of angular momentum
To be high on physics class, is just amazing
My physics professor back in college. Last day of school he rides on a unicycle while playing the fiddle.
Mine too! Go Aggies!
@@MrClubjub haha sorry MrClubjub. He was my professor at WVU before he moved to Texas! Let’s go Mountaineers!
Did he still play the fiddle while riding the Unicycle when he taught your class?
@@aneesrahil736 ya he did. Wrong Aggies tho. I meant Utah State University
A Great way to demonstrate the conservation of Angular Momentum!
Maybe this is what's happening with the universe expanding 😋
Universe doesn't really care about our current understanding of Physics. But, maybe.
@@the_science_fact The universe is what taught us about conservation of angular momentum and enforces it every time we test it (so far).
One of the reasons why I am passionate for science. So many cool things
Very cool display.
I need one of those collapsing balls. I remember being small enough to fit in one of them fully expanded back in like 2000. I was about 4!
They're a classic toy. I wonder if they're still being made?
My physics teacher demonstrated this by spinning on a spinny chair with his arms out holding weights, then pulling his arms in. Safe to say he was a little dizzy afterwards.
my teacher also did the same :)
Wow, love this demonstration.
That is so beautiful.
Like a gear or pully changing sizes . Cool!
I've seen dancers do this while spinning on their head and it LITERALLY looks like magic!
physics is so crazy and amazing
Moment of inertia is mass multiplied by square if the distance between the point and rotational axis , as u see the mass is same but the distance increases as we increase the radius.
I've always known this but I love simple examples like this
Already understood this, but it's so cool to see it in motion.
He's so happy physics still works
Making this damn thing with clips is also an another dedication
Genius, that is how teachers must work.
I always love in physics but this is so AWESOME, Thank you so much!!!
This is just beautiful
Perfect preparation to express moment of inertia.
If you're a physics lover , i know you smiled knowing what he is about to do, even before he explains
The fact I'm literally doing this in physics rn makes me feel these shorts are reading my mind.
He looked relieved it worked
The smile at the end is magnificent ❤🚀
Thats smile at the end, ive seen it its call passion for what you do.
Good example and illustration of conservation of angular momentum.
He got chills at end
I used to do that when spinning on a chair and stretching/flexing my legs horizontaly.
this is why you spin faster on a swing if you put your legs in. physics is amazing
thanks to this, it's speculated that black holes actually have donut-shaped singularities because all the rotation gets compressed into the smallest possible space, resulting in insane rotation speeds that stretch and reshape the singularity into a donut that is rotating ridiculously fast.
“donut shaped” is a stretch. They _are_ theorized to be rings, but since a ring with dimensions of 0,0,0 and a point with dimensions of 0,0,0 are indistinguishable from each other in every perceivable and measurable way except for the ring’s ability to spin.
That was really interesting :)
This phenomenon is the simplest one in physics which I've never been able to intuitively understand, which makes it fascinating for me. Physically it makes perfect sense, yet it's not something I would ever come up with by myself, I don't think. Another one of those, albeit a little bit more complex, is the temperature of the air you blow out being dependant on how wide you open your mouth, not how strong you blow. I'll never forget learning that in a high school physics class, having not noticed it an any earlier point in my life. Turns out I'd been mistaking the change in the speed of the air for the cause, whereas it had also been an effect. I was amazed and couldn't stop testing it afterwards. I'd been wrong about something seemingly so natural for so long! I remember sharing this newfound knowledge with a friend, he seemed unphased about it though, "of course that's how it works" he said, more or less. Before that day, I would have said the same thing about my explanation. Goes to show how much you can miss by never investigating the "obvious" :)
Well that was certainly a visual treat
I discovered this years ago as a kid by spinning like a top and then pulling in my arms and suddenly going light speed.
For anyone wondering why it works , it is analogous to a situation in which we put a linear momentum to a rest object now suppose if its mass is reduced then it will speed up because its inertia is getting lower similarly in rotational dynamics the inertia does depnds on radius also other than its mass so if somehow we reduces its radius then its inertia decreases which results in increase in angular velocity.
Very nice demonstration of the law of conservation of angular momentum.
Damn I love physics.
Ooooh, so that's what those things are used for, I played with this thing like 8 years ago
Thats an interesting way to show that principle
Personnaly my teacher demonstrated it with a rotative chair and some weight in each hand. He start by rotating with his arm extended then he slowly put is arm closer to his body which make him spin faster.
Quick explanation for those who didnt understand:
(1st ball)
since I=mr2
thus if we increase the radius, moment of inertia increases. Which means moment of inertia decreases the ball's abilty to produce angular rotation.
This causes a decrease in angular acceleration and thus angular velocity.
(2nd ball)
since I=mr2
and the radius decreased, which also decreases moment of inertia. By which the body's abilty to produce angular rotation increases.
Which causes an increase in angular acceleration and thus angular velocity.
Hope this helps!
This same concept is behind the unbelievable rotational speed of neutron stars who have angular velocity nearly 712 rotations percsecond
Really. Every kid learns it while watching a icedancer on a pirouette
I feel like a magic ✨
Me sitting on the rotating chair and opening and closing my arms everytime !! 😂
And that's why a pull slash gives you more impact than a push slash.
That is insane 🤯🤯
This would've been nice in my physics classes
I learned this during school recess. If your on the spiny chairs you just tuck and spin
Reason can be explained by the formula.
L = mvr
Since angular momentum(L) is conserved and mass is a constant, we have vr = constant.
Hence if radius is decreases, velocity increases.
Excelente exemplo para estudantes de física.
Muito bom.
Excellent demonstration
his contented smile at the end :3
Law demonstrated, conservation of angular momentum. Now, Angular momentum (L)= Iw (I= moment of inertia, w= angular velocity) and I= (integral of two variables )MR² ( M= mass of the object, R= radius) now since Iw is conserved, (Iw) initial= (Iw) final. And since, R is reduced(also M distributed uniformly), I also decrease, but M is constant. As a result, w increases in the final result.
What a illustration
I knew that would happen but what makes happy is how fast it speeds up.
Much like momentum, angular momentum is also conserved. As you decrease the moment of inertia, angular velocity increases to conserve angular momentum