Returns the apparent gravity on a space tether given its period, mass and distance
The rotation period of the tether in seconds (typically the same as the parent object for a classic space elevator)
The mass of the parent object in kilograms
The distance to the center of the parent object in meters
https://en.wikipedia.org/wiki/Space_elevator#Apparent_gravitational_field
Returns the apparent gravity on a space tether given its period, mass and distance