# Direction of angular velocity

• B
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Angular velocity is the rate of angular displacement about an axis. Its direction is determined by right hand rule.

According to right hand rule, if you hold the axis with your right hand and rotate the fingers in the direction of motion of the rotating body then thumb will point the direction of the angular velocity.

The direction of angular velocity is above or below the plane. But what does it mean? I mean in linear velocity the direction of velocity is in the direction of motion of body but what does it mean that body is moving in one direction while the direction of its angular velocity is in another direction?

## Answers and Replies

PeroK
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Angular velocity is the rate of angular displacement about an axis. Its direction is determined by right hand rule.

According to right hand rule, if you hold the axis with your right hand and rotate the fingers in the direction of motion of the rotating body then thumb will point the direction of the angular velocity.

The direction of angular velocity is above or below the plane. But what does it mean? I mean in linear velocity the direction of velocity is in the direction of motion of body but what does it mean that body is moving in one direction while the direction of its angular velocity is in another direction?

It means that angular velocity has a real vector nature. Look at the motion of a gyroscope. If everything were linear, the gyroscope would fall.

jbriggs444
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The direction of angular velocity is above or below the plane. But what does it mean?
It identifies the direction of the axis of rotation. Above or below the plane identifies clockwise or counter-clockwise. The magnitude indicates how fast it is rotating.

It happens to turn out that a three dimensional rotation rate has three degrees of freedom (pitch and yaw of the axis plus roll rate about the axis) just like a three dimensional position vector. It is convenient to represent it as such.