Speed in rigid-body-world

Hi Forum,
can somebody explain the value of “speed” in rigid body applications?
I’m asking because when I let a standing-up-pendulum falling down, from ~85° down to -90°(clock-wise), the nearly correct speed at the end is acieved only when turning the value of speed in the rigid-body-world pane up to 10. So is this the value to obtain the physical correct velocity, well, or nearly?
Probably it is described somewhere, but could not find where. Thanks in advance.