Never in my wildest dreams have I ever imagined young Will Smith teaching me Physics. Great video nonetheless.

This explanation exploded my mind and made me realize angular momentum is a vector resulting from a cross product. Well done, didn't know that.

this was the coolest angular momentum video I watched today

My high school physics teacher showed us this exact demonstration to us. He also used the same rotating platform, sat on it with his legs crossed. He then held a textbook in each hand. When he would bring textbooks close to him, he would spin faster. When he would hold them out, he would spin slower. Because the radius changes, causing the moment of inertia to change

I always played with bike wheels as a kid. Didn't understand why it would have a weird force feeling when moving a spinning wheel. Angular momentum. Thank you!

Dude this guy tutored me and caught me up to 3 months worth of Algebra in like 2 weeks the guy is a genius but also incredibly down to Earth.

I never knew that will smith belonged to MIT.

Now I know how to slow the Earth's rotation and make my days longer! Don't even need the rotating base, only need a bigger wheel... Thanks!

i love the simplicity of the demonstration.

I have done this experiment with wheel but I never thought to stand on a free base wheel Now I understand better

I would love to know how you built the turntable. Very well done.

Bravo! I learned something new. Your demonstration taught how am going to move forward with my design.

Question 1: What would happen if the wheel is held further away from the body? Question 2: If the angular momentum was very high, theoretically would the person be forced to spin and/or have a tendency to move towards an angle? Question 3: If the weight of the wheel was higher, would the angular momentum be higher? Thanks in advance folks!

Today I'm a Physician but I still remember being taught this lesson in High school Physics. My Physics teacher at that time volunteered me to teach the entire class this lesson because I was the smallest guy in the class and would be able to keep my feet off the ground as I sat on his swivel chair and got spun around by the spinning wheel.

The thumb rule is just used to find out the direction of angular momentum We choose sign acc to our convienience Sometime outwards is positive ,sometimes it can be negative

That’s mind blowing it is like magic even though I just studied this subject and took an exam on it

Bunu Türkçye çeviren adam gibi adam kimse çok teşekkür ederimm ona

i understand but i dont understand why it moves in one direction. i understand what he's saying but dont get it. it's just a wheel spinning. i dont get how the starting position of the wheel would make any difference in rotating. because flipped or not, it's just a spinning wheel.

I hated school was aways getting in trouble but luckily in high school Mr Colicott was my physics teacher he was so enthusiastic and passionate about science especially physics, he always tried to make our lessons fun and interesting I'm grateful to him because he introduced a love of learning to me that has carried me through life. Videos like this remind me of those lessons so cool to watch them with my son and then talk about it. He's still young and was already withdrawing from school work but stuff like this even relatively simple demonstrations like these make his eye light up like he's seen a magic trick. Can't wait to hear what questions he comes up with for me after we watch it. Excellent clear concise explanation and demonstration. Awesome stuff.

Thank you sir ! I did not know it has a postive or negative factor in it

0:50 It's not angular momentum, It's just the moment of inertia.

This is my kind of physics class

Great demonstration

This idea really helped me get through Statics and Dynamic!

Whatever you're standing on has a direction it wants to move in more than the other. You should spin either direction based upon how you hold the wheel, but you only spin one way meaning the thing you're standing on has friction one way but not the other. That is kind of a big part of this demonstration that you leave out.

I am lost, why is he not spining when the system angular mometum is -L ? does it mean that if he throw away the spinning wheel then the turn table will actually spin anti-clock wise because 0 - L = -L , meaning there is a default angular mometum L if he standing on the turntable without the wheel?

More vids with this guy pls

Nice and concise explanation! Very well done

Thanks for explaining it so clearly, Will Smith!

1:05. The moment of inertia depends on its shape and its mass. An object's moment of inertia depends on its geometry AND its density (whether or not the material of the object is uniform, etc.).

hey that demo was done in my uni too... That's why I kinda miss the physics lecture from few semesters back...

That was dope! More please.

Umm....how does the turntable rotate only in one direction and why does it not rotate when turning the wheel one way?

Dude.. I just wanna know what bearings he's using hahaha

Very interesting demonstration of conservation of angular momentum!

Loved it!

I took an "L" trying to learn this. . .

Thank you Will Smith for informative video!

I loved your sentences...simple and practical. Great video

Love it.. so fascinating .❤️

Thank you random internet video. I am now even smarter.

Angular momentum is not just conserved here because of your thumb rule It conserved because all the exteral forces acting on body like gravity is parallel to the axis of rotation

Excellent video

Very well explained😍

The set-up of this is fundamentally wrong. When he's standing on the turntable and rotates the wheel, it is correct that there is a Newton's-third-law force in the opposite direction. However, that is not the force that is making him spin: it's not the opposite direction. The opposite direction to him turning the wheel anticlockwise (as seen from our point of view) is a force that tries to turn him clockwise about a horizontal axis through his chest, not about a vertical axis down his spine. The reaction to him flipping the wheel over would turn him upside down, not rotate him on the turntable. The reason it doesn't turn him upside down is that the frictional force through his feet opposes this.

Unfortunately this video is again a hot-mess. At the final sum up you've reversed the directions that you had used in the explanations. In the demos you started with +L as the starting point then the flip to -L is what impels your body into the balancing rotation of +2L. YET, In the final summary, your body was spinning clockwise which meant -2L as a reaction to +L. Haha Oh dear, when you fail at the correction video.

KZfaq recommend legend after 4 years

Thank you mate very cool

People invented the wheel thousand of years ago, and we still have to explain nowadays how it works. 😅

God I want to study at MIT please help me!!

I was totally wanting him to do cartwheels when he flipped the wheel vertical

This helped! Thanks :)

Bruh what’s will smith doing here

Before we catch aliens we must first learn basic physics here that applies to everything and will smith is teaching us

This is amazing

Has anyone done this but the bottom is rotating (hooked up to a motor I imagine with a "free turning table on top") causing the person to rotate e.g: in a clockwise direction, and then the wheel either makes you rotate twice as fast in one orientation as the forces add or stop in the opposite orientation as the forces cancel out? I feel this would help demonstrate this point even better. Sorry if I'm not very clear with this.

This video really helped. Thank you

Totally a new knowledge for common people

Nice explanation

One of my mentor used the wheel chair to explain us angular momentum conservation

if anyone needs a very good and In a hurry of the explanation of angular momentum and how it works. check this dude out.

This looks like its straight out of a movie

Good job young man!

Hey I've got a question. Assuming the system was in equilibrium at -L means that the an outside force created the equilibrium while you were already on the turntable, (you were on the turntable and then the wheel was spun up). and that's why you were only ever able to spin in one direction.

Beautiful

Hope they're learning more than that at MIT.

Awesome!

Watching the rest of the video with my hand like this 👍

Ayoo this trailers hype! Excited to see this movie WiLL.

1:30 no external torques and not external forces, or net external torque=zero When you dive, there is an external force but the angular momentum is conserved.

Daaaaaammmnnn so interesting. Thanks

Levee; is one of the things that changes can steal from the opposite that's against; among many many more.

Uncle Phill will be proud of you, Great Video

Torque. Same reason helicopters use a main rotor for lift, and a tail rotor for stable flight. The tail rotor is spinning counter to the main rotor. Without the tail rotor, the helicopter's entire fuselage would spin like a top, counter to the main rotor. Airplane propellers are a little different but do the same thing, they are called "tractor propellers". Planes have wings, a rear stablizer and use an airfoil. Their wings produce the lift. Copter's don't, they rely solely on the pitch of the main rotors for lift. Plane props spin but the plane remains stable and does not spin.

Bro u r just awesome

I get it perfectly!! THX!

If you had started with the bike rim spinning in the opposite direction, would it spin you around the opposite direction when you flipped the wheel?

Well explain my dude

This is how "reaction flywheels" on space craft work.speeding up or slowing down any wheel on a given axis will alter the vehicles attitude.

Why didn’t the platform rotate the same speed, opposite direction before it was flipped?

Amazing thank sir

Short, sweet and to the point, as all things should be

We’ve tried this on a Pilates spin plate but the friction must be too much as we don’t spin. So how to make one of these bases?

So If I add a mass to that system, but wheel is not moving, could I say angular momentum is not conserved?

Merci Theobabac de tes explications !

Legends say : he is still spinning like that

This way you balance the y-component of the angular momentum. But if initially, you would hold the wheel vertically, so that it spins around a horizontal axis then the angular momentum is directed to the side. If you then turn the axis to be vertical, you start spinning in order to balance the vertical component of the angular momentum but what does balance the lost horizontal component of the angular momentum?

what if you keep flipping it the same direction (which will require you to switch hands after each flip) will you keep spinning faster and faster? i’m sure the wheel slows down but you can just spin it more and keep flipping, is it a speed unlock?

loved it

That was cool!!

Cool! I built a working model of an amusement ride based on this principle for my physics class.

Why don't you spin counter clock wise when you turn the wheel over???

Damn MIT now inventing new physics

Man this guys smart asf hes def going to a schoo like MIT

what happens if you take the spinning wheel while pinning does it increase the speed that you spin.. and what if you are spinning opposite direction would it stop your momentum?.. hmmm

What happens if the wheel is out of balance?? Does it make the axle shake and change the spin?

Totally wholesome

What if I turn the wheel to the left to times ? I start spinning to the other side?

i understood like, nothing but sounds incredible

What happens if he keeps the orientation of the wheel but switches which hand is holding it? Or holds it in front of himself with both hands?