For an overview on creating, visualizing, and simulating mechanical constraints, including RopeConstraint, see Mechanical Constraints. Also see Roblox Units to understand how Roblox units compare to metric units.
A RopeConstraint prevents two attachments from separating further than a defined Length. The attachments can move closer together than this length and both can freely rotate. Restitution defines the elasticity of the attachments when they reach the separation limit specified by Length.
This constraint can also be powered to behave as a motorized winch.
Winch
If a rope's WinchEnabled property is enabled, it attempts to translate the attachments to a set separation specified by WinchTarget, effectively the target length of the rope in studs. This translation is controlled by WinchSpeed, WinchResponsiveness, and WinchForce.
WinchSpeed must be a positive value, used to either contract or extend the rope length to WinchTarget. Setting a negative speed will revert to 0, not reverse the winch servo direction.