Why is the right-hand rule used for both current and angular momentum?

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The right-hand rule is applied to both electric current in wires and angular momentum in gyroscopes due to the vector nature of these phenomena, where the direction of the vectors is perpendicular to the plane of rotation. This convention simplifies understanding and communication in physics, as it provides a consistent method for determining directionality. The discussion highlights that while the right-hand rule is standard, there are nuances, such as the distinction between the axis of rotation and the plane of motion. The concept of "handedness" is emphasized as a convention rather than a fundamental property. Overall, the right-hand rule serves as a crucial tool in physics for visualizing rotational dynamics and magnetic fields.
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Why does the right-hand rule apply to both current in a wire and angular momentum in a gyroscope? Is there there a common denominator between the two effects?
 
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Both rotation and the curl of magnetic fields are expressed using vectors which are perpendicular to the plane in which the rotation occurs. In any such situation, it is possible to define the perpendicular vector in two distinct ways. Thankfully, physicists long ago decided to use a single convention for all such decisions.

- Warren
 
chroot said:
perpendicular to the plane in which the rotation occurs.

I think it is more accurate to say "perpendicular to the axis/vector about which the rotation occurs".

I'd agree that right-hand coordinate systems are the norm, but circular/elliptical polarization is still a two-handed convention within a one-handed system.

Regarding the gyroscope, if you use the "curl" of the fingers on your right hand to indicate positive rotation about the vector your thumb points in, you need only point your thumb in the opposite direction (or swap hands) to change the sign of the angular velocity of the gyroscope with respect to "the thumb". Handedness is only a convention - I wouldn't try to read more into it than that.

Regards,

Bill
 
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