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‫Welcome back.

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‫In this video, we will very quickly talk about the direction of a rotation vector when you have some

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‫kind of random object and it has some kind of velocity in this direction, well, then you intuitively

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‫know that this object is going to move in this direction.

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‫However, what would be the direction of rotation?

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‫Let's say that here you have random object rotating and it is rotating like shown here in red and here

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‫in blue.

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‫This is the rotation plane.

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‫So this red is drawn on this blue plane.

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‫In the direction of this rotation is this Green Arrow, which is perpendicular to the rotation plane.

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‫In other words, this green vector is perpendicular to this blue plane.

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‫So here you can see this perpendicular sign.

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‫And so let's say that this object is rotating at, let's say, Alpha Dot or the Alpha DETI.

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‫Let's see, it's rotating at 10 radians per second.

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‫So this is angular velocity and angle of velocity, a vector, which means that it also has to have

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‫a direction.

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‫And so if this object rotates 10 radians per second on this blue rotation plane or like you see it in

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‫red, then the direction of the angular velocity vector would be perpendicular to this rotation plane.

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‫So it would be this Green Arrow.

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‫So this would be your angular velocity vector.

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‫And then the length of this arrow would be the magnitude of the velocity vector, which would be 10

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‫radians per second.

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‫And if instead of angular velocity, you had angular acceleration, let's say five radians per second

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‫squared, then if this angular acceleration happens on this blue rotation plane, then again, the direction

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‫of this vector would be perpendicular to this plane, either in this direction or in the opposite direction,

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‫depending on the right hand rule.

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‫Also, the same would apply to an angular position vector.

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‫Let's see if you just have alpha equals, let's see, two radians.

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‫So the object has rotated to radians, but then you ask in which direction.

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‫And so this arrow would give you the direction, which means the rotation happens around this arrow.

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‫So the object rotated to radians around this arrow.

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‫So you have to grab this arrow with your right hand and then you see where the sun points and then you

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‫know the direction of the vector and the same thing.

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‫You can have a talk or a moment.

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‫Remember, talking a moment are actually the same thing.

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‫Let's say equal seven Newton meters.

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‫Again, a moment creates rotation.

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‫So it is also related to rotation.

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‫So, again, if you have a moment, whose direction is this Green Arrow, then you know that this object

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‫wants to start rotating like shown here in red.

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‫So the direction of a rotation is perpendicular to the rotation plain.

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‫And if there is a change in the rotation direction, then this would be the change of it and this would

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‫be your new rotation vector.

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‫That means that also the rotation plane would adjust itself so that it would now be perpendicular to

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‫this vector.

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‫So I hope it's clear now.

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‫Thank you very much and see you in the next video.