Spinning

Hi Vsauce Michael, do you want my head delivered to your door in a box? Well, what a shame, I only have one head and I already ordered it and besides my neck is like pure muscle, this head will never make it to the next best option. is what actually comes in the Vsauce curio box, it's packed with scientific equipment designed by us, it's pretty amazing and a portion of all proceeds goes to Alzheimer's research, so a subscription is not only good for your brain, it's good for all of our brains now, if you subscribe right now, there's still time to get this box, the latest one, it's full of brain food, including the subject of this video. a gyroscope, if you hold a gyroscope in the palm of your hand upright like this, it will fall.

Not too surprisingly you'll see that the trick is to take the included rope and thread it through a hole and then turn the disc until the rope is wound over and over again and once it's wound up enough, hold the outside and give it a whirl. the rope in a firm position. pull, ah yes, now the gyro seems to defy gravity, the

spinning

shaft is stuck in place almost cosmically, if you could make this spin long enough you could see how that access moved, but not because it had actually been moved, because you and the Earth move around it, that's where the gyroscope gets its name.

You can use it to observe the Earth's gyroscopic rotation like Leon Foucault did in 1852 when the device was named after him, but how does it work? Why do things spin so stable too? Check this out, if I give it a good spin and then hang it on its own rope sideways, it will stay parallel to the ground, but process to get to the bottom of what's going on or if, as the cool kids say these days, start by imagining yourself swinging . a ball around your head tied to a string, although the ball follows a curved path, its speed at any given instant is a straight line tangent to its path, you can prove it to yourself by releasing it, the ball will be launched at the speed it had in the moment The moment you release it, it does not curve or move away directly as the string spins, it keeps the ball always the same distance from the center, which means continually changing the direction of the speed of the ball, now that requires strength and in this case that force is The tension in the rope generates the same intermolecular forces that attract the neighboring rope molecules to each other and are the reason why the rope not only disintegrates, but also resists the impulse of the ball that acts on it, so that its speed changes each following instant to continue forever. a circular path this center looks for the force that acts on the ball is called centripetal force it can be provided by a rope an entire disk of material something invisible like gravity or from the other side by a wall or banked track side note notice that there is no force acts on the ball going directly outward, away from the center, what we often hear called centrifugal or centrifugal force, you know the force you seem to feel when you lock hands with someone and you both spin and feel pushed back or forward. back. when a car urine spins rapidly and you are suddenly thrown away from the center, the thing is that this seemingly outward directed force is not a force at all, it is actually just the inertia of an object, the path the object would take if no other forces acted on it.

When blocked by a force, a centripetal force on short enough time scales, an inertial path may seem opposite to a centripetal force, but if it is allowed to follow its inertial path for a while, the difference becomes clearer. Here is a ball in orbit if the centripetal force is removed it will continue on a path tangent to its previous circular, the contour represents where the ball would be if it had not been launched now, at first the separation between the two appears to occur directly away from the center, but if allowed to continue, a more interesting path emerges from the perspective of the contour still moving counterclockwise, the solid ball appears to be receding and crawling clockwise, this It is due to the Coriolis effect which we will talk about soon, but first let's move a few things forward.

It could really be anything, but I would love to use this ball. It's great, it has fiber optic properties. It would be great to put them in curio boxes in the future. I'll see what I can do anyway if I push the ball it will move. in the direction of my force is quite simple, but if the ball moves before I touch it, its speed does not simply disappear, but both combine and the ball moves according to their sum, the smaller its initial impulse , the greater this angle will be. Now let's go back to circular motion imagine a satellite orbiting the Earth, its speed is, as we showed before, at all times tangent to its circular path, a centripetal force of gravity continuously oscillates its speed so that every 90 degrees it begins to point each time more in the opposite direction than he used to.

Just like with the ball, a downward force will not send it straight down, but rather the vectors combine resulting in a new path like this. 90 degrees forward reaches the maximum distance it will travel in the direction of our force before returning to the key point. here is that a downward force at this location did not move the orbit this way, it moved the orbit this way tilting it 90 degrees ahead of where we act. Now imagine the satellite as a small piece of our gyroscope pushing down here will cause the piece. assume a path that would take it like this, but of course, since the disk is solid in all its pieces, they push and pull on each other quite rigidly, the gyroscope tilts like this or if the gyroscope rotates around a point below its center, so if the gyroscope wasn't

spinning

, pushing it down here would only have caused this to happen, but when something spins, its components have other vectors that you have to consider.

I learned a fun demonstration of this in an excellent video by Matthias Wandel. This is a cardboard. disk I cut it myself, I can balance it on the end of a pen like this and if I blow on the side closest to me, it tilts, not very surprising, but if the disk rotates and I blow on the same place, it tilts towards the right and if I blow on the side closest to you instead of leaning towards you, it leans to the left if instead of applying my force in one place all the time I apply the force wherever the downward inclination is greatest, the tilt will do it.

I slide around and around Look, I'm out of breath, but the point is that this is exactly what happens when a gyro here on Earth spins up and tilts, the tilt slides around, this is called precession, it What's happening is actually very similar to my breathing moves, except instead of my breathing, it's gravity, no matter how perfectly vertical a gyroscope is, it won't stay that way forever. Any deviation, no matter how slight, will allow gravity to form a torque. A torque occurs whenever a force rotates an object about a pivot. point, if the disc is spinning, the effect of that torque will move 90 degrees forward in the rotation, but now the torque is operating this way, so its effect will have to be felt 90 degrees forward and so on, and Well, what do you know?

The gyroscope processes now, if it weren't for friction and air resistance and other forces interfering with this disk, it would just process at the same angle forever, but of course we live in a world with friction and air resistance and all that good stuff, so the puck spins downward in the same way that a slower moving ball deflects at a steeper angle as the puck slows down. Each piece of it receives a steeper and steeper orbit around the gyroscope, tilting lower and lower until it hits the ground and finally decelerates. To stop you, look at this bicycle wheel, it's like our gyro but bigger.

I have a rope tied to its handle right here, so when it's lifted like this, gravity applies a torque, so it's equivalent to a force up here in this direction and a force on the wheel down here in this direction, if the loose, those two forces will do their job, well, quite predictably, if I spin this wheel, there will be other vectors in play, a part of the wheel will move, say, counterclockwise or together with the rest. of the wheel down here will have a speed tangent to its circular path but also a torque that pushes it in this way will make its orbit as in our gyroscope move like this, this force will have its maximum impact 90 degrees forward in the rotation, so that the The wheel will spin like this, but well, there's still a couple here pushing the bottom of the wheel like this, moving it 90 degrees forward, we see that the wheel will still spin and in fact, that's what it's going to do if I can Raise it at a fast enough speed, then an even larger rotating object is the Earth and we are all on it bound by friction and gravity for the journey.

A journey with some surprising consequences. A helicopter cannot simply rise from the ground and remain stationary. and allowing the Earth to rotate beneath it doesn't work that way, this is because the helicopter, the ground it used to be on and the air around it also travel with the Earth's spin, but if you had a magic paper airplane, that one could actually be launched. away and decided to throw it directly north, towards your friend. The Earth's spin would come into play no matter how accurate your aim was, each time you would find the plane drifting a little to the east as if pushed by some mysterious force and so would your friend. north he would discover that his plane launched south directly toward you would always drift a little to the west.

This is called the Coriolis effect. You are both on Earth and you are both always north and south of each other, but on one day your friend is closer to the pole. travels a shorter total distance around its shorter distance at the same time your friend moves slower than you, meanwhile your plane rotates at your fastest speed and continues to have this speed after you launch it as it moves towards the pole in which it is located. slower and slower things, so you get ahead of them and move east in the direction of the Earth's spin, your friends play meanwhile you find yourself among things that move faster and faster and you fall behind.

There is a vertical version of the Coriolis effect, as well as an object suspended very high. Just above, you'll actually fall a little to the east if you drop it and anything you throw up at it will curve to the west. The taller object whose circular path is larger covers more distance at the same time as you. speeds don't simply disappear when things are dropped or thrown, so both miss the mark; It's also why the directly outward-pointing force you feel when you turn is fictitious—your inertial tendency to move in a straight line takes you away from the path you're taking.

We go where things have to have higher speeds to rotate at the same rate. If you fly long enough you will notice that you are falling behind your original rotation rate, not always straight out, eventually you lose weight fast but not mass with this strange one. trick discovered by a Hungarian nobleman and physicist people who think the earth is flat hate it is called the bush effect in the early 1900s Baron Roland von Hood Bush was observing gravity measurements taken on ships at sea and noticed that the readings were lower when the ships were traveling east and higher when they were traveling west, further research found that yes, in fact, when you travel on foot in a car, on a bicycle, in a plane, it doesn't matter, you weigh less when travel and more when traveling west, in fact, a plane flying east to the equator experiences an apparent weight reduction of about 0.9 percent, so if you want to quickly lose a little more than a pound , about half a kilo, get on that plane, which causes this effect.

When you are rotating with the Earth, you have a linear velocity, but gravity, a centripetal force, always resists this, if gravity were disabled and the Earth remained whole, you would be thrown on a tangent that rises above your usual path , for this reason your inertial tendency to take this tangent path is a kind of elevation. It's not enough to get you off the surface, the earth doesn't spin fast enough for that to happen, but just as I can lift something that's on a scale and make it weigh less without taking it completely off the scale, your inertial path will also take you off the surface. elevates Traveling just a little to the east increases the speed that the Earth's spin gives you and provides more of this type of lift in a direction away from the surface, making you lighter; on the other hand, traveling west decreases your speed in that direction, which reduces its lifting effect on your weight. thinkingon this and maybe even weighing myself very accurately as I travel the country with live brain candy, you already got your tickets, don't wait, it's very, very exciting and I can't wait to get the chance to see you all in person. and be more interactive with this sort of thing and do it on a much larger and louder personal scale.

Also subscribe to the curiosity box for more mental dynamite. It's fantastic and it helps a lot because I fully support it. I am very proud. of this and you know what, subscribe to dong while you're at it, my latest video is about some of my favorite free physics simulators on the internet. You all are great. I appreciate your time and, as always, thanks for watching.