Angular position is arc length over radius

To describe the rotation of a rigid body about a fixed rotational axis, a reference line is assumed to be fixed in the body, perpendicular to that axis and rotating with the body. The angular position of this is measured relative to a fixed direction and is expressed as a ratio of the arc length of a circular path and its radius (distance to the axis).

Links:

1. Wikipedia, similar concept.

2. openstax, table 6.2, first line.

angular_position

angular_distance of the body.

Symbol:

theta

Latex:

\(\theta\)

Dimension:

angle

arc_length

arc_length of the curve traced by the body’s movement.

Symbol:

s

Latex:

\(s\)

Dimension:

length

distance_to_axis

distance_to_axis of rotation, or radius of rotation.

Symbol:

r

Latex:

\(r\)

Dimension:

length

law

theta = s / r

Latex:

\[\theta = \frac{s}{r}\]